ARDMS Vascular Technology (VT) Exam — Questions and Answers
Question 1: What is the normal toe-brachial index (TBI) value in a healthy adult?
- >0.40
- >1.00
- >0.60 (Correct answer)
- >0.80
Correct answer: >0.60
A normal TBI is ≥0.70 in most references, with values below 0.60 generally considered abnormal and indicating significant digital arterial disease.
Question 2: In spectral Doppler, the filling-in of the clear space under the systolic peak is known as spectral broadening. This finding is most commonly associated with:
- Disturbed or turbulent blood flow. (Correct answer)
- A Doppler angle of exactly 90 degrees.
- Laminar flow in a large, straight vessel.
- A Doppler gate placed in the center of the vessel.
Correct answer: Disturbed or turbulent blood flow.
The clear area under the systolic peak, or 'spectral window,' represents the uniform velocity of red blood cells in laminar flow. Turbulent flow involves red blood cells moving at a wide variety of speeds and in multiple directions. This range of velocities fills in the spectral window, causing the appearance of spectral broadening.
Question 3: A sonographer reports frequent right shoulder and neck pain. Which of the following is the most effective ergonomic practice to mitigate the risk of a work-related musculoskeletal disorder (WRMSD)?
- Scheduling similar exam types back-to-back to improve efficiency.
- Performing the majority of exams while standing to improve posture and core strength.
- Gripping the transducer with increased force to maintain better control.
- Adjusting the exam table and chair so the scanning arm's angle of abduction is less than 30 degrees. (Correct answer)
Correct answer: Adjusting the exam table and chair so the scanning arm's angle of abduction is less than 30 degrees.
Proper ergonomics are crucial for preventing WRMSDs in sonographers. Adjusting the exam table and personal chair height to keep the scanning arm close to the body (abduction < 30 degrees) and the elbow at approximately 90 degrees significantly reduces strain on the shoulder and neck muscles. Gripping the transducer too tightly and prolonged standing increase strain, while performing varied exam types is recommended over repetitive scheduling.
Question 4: Based on Poiseuille's law, which of the following factors has the greatest influence on resistance to blood flow?
- Pressure gradient
- Vessel radius (Correct answer)
- Vessel length
- Blood viscosity
Correct answer: Vessel radius
Poiseuille's law demonstrates that resistance to flow is inversely proportional to the vessel radius raised to the fourth power (r⁴). This exponential relationship means that even a very small change in the radius of a vessel will cause a very large change in resistance, making it the most impactful factor.
Question 5: Which clinical scenario would MOST warrant transcutaneous oxygen pressure (TcPO2) measurement as part of peripheral arterial physiologic testing?
- Diagnosing proximal aortoiliac occlusion
- Differentiating claudication from spinal stenosis
- Screening for PAD in an asymptomatic patient with diabetes
- Predicting wound healing potential in a patient with a non-healing foot ulcer (Correct answer)
Correct answer: Predicting wound healing potential in a patient with a non-healing foot ulcer
TcPO2 measures tissue oxygenation at the skin surface and is used to predict amputation wound healing potential; values <20-30 mmHg predict poor healing.
Question 6: Which artifact appears as a bright echogenic line with posterior shadowing caused by total reflection at a gas interface?
- Clean shadowing
- Dirty shadowing (Correct answer)
- Comet-tail artifact
- Mirror image artifact
Correct answer: Dirty shadowing
Dirty shadowing (reverberation shadowing) occurs at gas interfaces where multiple reflections create a heterogeneous shadow with internal echoes.
Question 7: During intraoperative TCD monitoring of a carotid endarterectomy, which finding should prompt the surgeon to insert an intraluminal shunt?
- MCA mean velocity increase of 15% after clamping
- MCA mean velocity decrease of more than 50% from pre-clamp baseline (Correct answer)
- Pulsatility index increase of 0.2 units
- Appearance of spectral broadening in the MCA waveform
Correct answer: MCA mean velocity decrease of more than 50% from pre-clamp baseline
A >50% drop in ipsilateral MCA mean velocity after carotid cross-clamping indicates inadequate collateral perfusion and cerebral ischemia risk. This threshold is widely used as the criterion for shunt placement to maintain cerebral blood flow during the endarterectomy.
Question 8: During splenic artery duplex evaluation, the normal waveform pattern reflects which hemodynamic state?
- Monophasic flat waveform with no diastolic component
- Low-resistance flow with continuous forward diastolic flow (Correct answer)
- High-resistance triphasic flow with brief flow reversal
- Pulsatile bidirectional flow synchronous with respiration
Correct answer: Low-resistance flow with continuous forward diastolic flow
The splenic parenchyma is a low-resistance vascular bed, so the splenic artery normally displays continuous forward diastolic flow similar to other visceral vessels.
Question 9: What is the primary mechanism by which turbulent flow contributes to aneurysm wall stress?
- Laminar flow disruption causes thrombus embolization
- Elevated venous pressure transmits back to the arterial wall
- Decreased velocity reduces oxygen delivery to the adventitia
- Increased wall shear stress causes smooth muscle cell apoptosis and extracellular matrix degradation (Correct answer)
Correct answer: Increased wall shear stress causes smooth muscle cell apoptosis and extracellular matrix degradation
Turbulent and oscillatory wall shear stress promotes inflammatory cell infiltration, MMP activation, and degradation of elastin and collagen.
Question 10: Which finding on continuous-wave Doppler examination is MOST indicative of a hemodynamically significant proximal stenosis?
- Biphasic signal with mild spectral broadening
- Monophasic, low-velocity signal with loss of reverse flow component (Correct answer)
- High-pitched, multiphasic signal with clear window
- Triphasic waveform with normal peak systolic velocity
Correct answer: Monophasic, low-velocity signal with loss of reverse flow component
A monophasic, damped signal distal to a significant stenosis results from loss of pulsatility as pressure energy is dissipated across the lesion.
Question 11: Which duplex finding best distinguishes carotid plaque hemorrhage from calcified plaque?
- Hemorrhagic plaque appears highly echogenic with acoustic shadowing
- Hemorrhagic plaque always shows posterior enhancement
- Calcified plaque appears isoechoic to surrounding tissue
- Hemorrhagic plaque appears hypoechoic or heterogeneous without shadowing; calcified plaque shows dense shadowing (Correct answer)
Correct answer: Hemorrhagic plaque appears hypoechoic or heterogeneous without shadowing; calcified plaque shows dense shadowing
Intraplaque hemorrhage appears hypoechoic or heterogeneous on ultrasound, while calcification produces bright echoes with posterior acoustic shadowing.
Question 12: Which of the following is a primary advantage of Power Doppler when compared to standard Color Doppler?
- It has a higher sensitivity to slow flow states. (Correct answer)
- It provides precise velocity measurements.
- It clearly displays the direction of blood flow.
- It is less susceptible to motion (flash) artifact.
Correct answer: It has a higher sensitivity to slow flow states.
Power Doppler displays the amplitude (power) of the Doppler signal rather than the frequency shift. This makes it more sensitive to the presence of flow, especially in low-flow or slow-flow situations where Color Doppler may not detect a signal. However, it does not provide information about velocity or direction and is more prone to flash artifact.
Question 13: In segmental limb pressure testing, what finding is characteristic of isolated popliteal artery disease?
- Gradient between ankle and metatarsal pressures
- Gradient between above-knee and below-knee segmental pressures with normal thigh pressures (Correct answer)
- Symmetrically reduced pressures at all levels bilaterally
- Gradient between brachial and proximal thigh pressures
Correct answer: Gradient between above-knee and below-knee segmental pressures with normal thigh pressures
Isolated popliteal disease produces a pressure drop between the above-knee and below-knee cuff levels with normal proximal thigh pressures, localizing disease to the popliteal segment.
Question 14: Which collateral pathway opens when the ipsilateral ICA is occluded and the contralateral ICA is patent?
- Posterior communicating artery
- Basilar artery-to-MCA anastomosis
- Ophthalmic artery retrograde flow
- Anterior communicating artery (Correct answer)
Correct answer: Anterior communicating artery
The anterior communicating artery connects the two ACAs, allowing contralateral ICA flow to supply the ipsilateral hemisphere via the ACoA.
Question 15: A patient has a known popliteal artery aneurysm. Contralateral popliteal artery evaluation is recommended because:
- Insurance requires bilateral documentation
- Popliteal aneurysms are bilateral in approximately 50% of cases (Correct answer)
- Contralateral aneurysms are always larger and more dangerous
- The contralateral limb is at higher risk for DVT
Correct answer: Popliteal aneurysms are bilateral in approximately 50% of cases
Popliteal artery aneurysms are bilateral in roughly 50% of patients, making contralateral evaluation a standard part of the examination.
Question 16: Which velocity criterion is most widely accepted for diagnosing ≥60% renal artery stenosis on duplex ultrasound?
- Renal artery PSV ≥300 cm/s regardless of RAR
- Acceleration time >100 ms alone
- Renal artery PSV ≥100 cm/s with RAR ≥2.0
- Renal artery PSV ≥180–200 cm/s with RAR ≥3.5 (Correct answer)
Correct answer: Renal artery PSV ≥180–200 cm/s with RAR ≥3.5
Most laboratories use a renal artery PSV of 180–200 cm/s combined with an RAR ≥3.5 as the threshold for hemodynamically significant (≥60%) stenosis.
Question 17: A vascular technologist performing a surveillance duplex identifies a new, complete thrombotic occlusion of a previously patent femoral-popliteal bypass graft. What is the MOST appropriate immediate action?
- Notify the patient's family and recommend emergency department evaluation
- Communicate the finding urgently to the ordering physician or on-call clinical team before the patient leaves (Correct answer)
- Repeat the exam in 24 hours to confirm the finding
- Schedule a 3-month follow-up duplex and note findings in the report
Correct answer: Communicate the finding urgently to the ordering physician or on-call clinical team before the patient leaves
Acute graft occlusion is a limb-threatening emergency requiring immediate clinical decision-making (thrombectomy, thrombolysis, or revision). The technologist must notify the responsible physician or clinical team while the patient is still present so that timely intervention can be arranged. Documenting without communication causes dangerous treatment delays.
Question 18: For the experience-based RVT pathway, in which imaging modality must the documented clinical studies primarily be performed?
- CT angiography
- Diagnostic vascular ultrasound (Correct answer)
- Nuclear medicine perfusion imaging
- Magnetic resonance angiography (MRA)
Correct answer: Diagnostic vascular ultrasound
The clinical experience must consist of diagnostic vascular ultrasound examinations, reflecting the core competency tested by the RVT credential.
Question 19: On duplex ultrasound, a post-stenotic flow pattern distal to a high-grade ICA stenosis is characterized by:
- Reversed diastolic flow
- High-resistance monophasic waveform
- Tardus-parvus waveform with delayed systolic upstroke (Correct answer)
- Normal triphasic waveform
Correct answer: Tardus-parvus waveform with delayed systolic upstroke
Tardus-parvus (slow-rising, rounded systolic peak with reduced amplitude) waveform is the classic post-stenotic pattern seen distal to significant stenosis.
Question 20: In pulsed-wave Doppler, aliasing occurs when the Doppler shift frequency exceeds:
- The transducer frequency
- Half the pulse repetition frequency (Nyquist limit) (Correct answer)
- The wall filter setting
- The sample volume depth
Correct answer: Half the pulse repetition frequency (Nyquist limit)
Aliasing occurs when the Doppler shift exceeds the Nyquist limit (PRF/2), causing the waveform to wrap around and appear on the opposite side of the baseline.
Question 21: Which duplex criterion is MOST specific for occlusion (rather than high-grade stenosis) of a bypass graft?
- Monophasic waveform at the graft origin
- Complete absence of color flow and Doppler signal within the graft lumen (Correct answer)
- Reversed diastolic flow at the distal anastomosis
- PSV <20 cm/s throughout the graft
Correct answer: Complete absence of color flow and Doppler signal within the graft lumen
Complete absence of color flow and spectral Doppler signal throughout the graft lumen is the definitive duplex finding of graft occlusion.
Question 22: Which factor most often determines whether an RVT earns a supervisory versus staff-level salary?
- Geographic region alone
- Whether they work day or night shifts
- Years of experience combined with demonstrated leadership and management responsibilities (Correct answer)
- The brand of ultrasound machine they operate
Correct answer: Years of experience combined with demonstrated leadership and management responsibilities
Supervisory salaries reflect both accumulated years of clinical experience and the assumption of formal management duties such as scheduling, QA oversight, and staff evaluations.
Question 23: A patient with claudication has an ABI of 0.62 at rest. After treadmill exercise, the ABI drops to 0.31 and takes 8 minutes to recover. What does this pattern indicate?
- Venous insufficiency masking arterial disease
- Moderate-to-severe arterial disease with poor collateral compensation (Correct answer)
- Mild arterial disease with good collateral flow
- Normal exercise response with physiologic hyperemia
Correct answer: Moderate-to-severe arterial disease with poor collateral compensation
A post-exercise ABI drop >20% with prolonged recovery (>3 minutes) indicates hemodynamically significant arterial disease with inadequate collateral circulation.
Question 24: A false-negative rate of 12% is found during a QA audit of carotid duplex studies compared to angiography. Which action is MOST appropriate?
- Increase the stenosis threshold to reduce false negatives
- Accept the rate as within normal lab variation
- Conduct a root cause analysis to identify systematic scanning or interpretation errors (Correct answer)
- Remove the outlying technologist from carotid scanning duties immediately
Correct answer: Conduct a root cause analysis to identify systematic scanning or interpretation errors
A root cause analysis identifies whether the false negatives stem from protocol deviations, equipment issues, or interpretation criteria, enabling targeted corrective actions.
Question 25: A patient presents with claudication. The right brachial pressure is 140 mmHg and the left brachial pressure is 130 mmHg. The right posterior tibial artery pressure is 70 mmHg and the right dorsalis pedis artery pressure is 65 mmHg. What is the correct Ankle-Brachial Index (ABI) for the right leg?
- 0.46
- 1.07
- 0.96
- 0.50 (Correct answer)
Correct answer: 0.50
To calculate the ABI, the highest ankle pressure on one side is divided by the highest of the two brachial pressures. In this case, the highest right ankle pressure is 70 mmHg (from the posterior tibial artery) and the highest brachial pressure is 140 mmHg. Therefore, 70 / 140 = 0.50. This value indicates moderate to severe peripheral arterial disease.
Question 26: A hypoechoic structure on ultrasound indicates that it:
- Reflects fewer echoes than surrounding tissue (Correct answer)
- Contains no internal echoes at all
- Reflects more echoes than surrounding tissue
- Contains calcification with posterior shadowing
Correct answer: Reflects fewer echoes than surrounding tissue
Hypoechoic means the structure appears darker (fewer/lower amplitude echoes) compared to adjacent tissue, not completely echo-free.
Question 27: After endovenous laser ablation (EVLA) of the great saphenous vein, which duplex finding at 1 week indicates a successful procedure?
- Unchanged GSV diameter with reduced flow velocity
- Partial recanalization with turbulent flow
- Residual flow with reduced diameter
- Closure of the GSV with absence of flow and echogenic occlusive thrombus within the treated segment (Correct answer)
Correct answer: Closure of the GSV with absence of flow and echogenic occlusive thrombus within the treated segment
Successful EVLA results in GSV occlusion demonstrated by absence of color flow and an echogenic thrombus filling the treated lumen.
Question 28: A vascular technologist performing renal artery duplex uses the renal-to-aortic ratio (RAR). What RAR value is considered significant for renal artery stenosis?
- RAR > 5.0
- RAR > 7.0
- RAR > 1.5
- RAR > 3.5 (Correct answer)
Correct answer: RAR > 3.5
A renal-to-aortic ratio > 3.5 is the established threshold for hemodynamically significant renal artery stenosis (typically ≥ 60%).
Question 29: A vascular technologist is performing a Transcranial Doppler (TCD) examination through the transtemporal window. To identify the middle cerebral artery (MCA), what is the expected direction of blood flow relative to the transducer?
- Antegrade (towards the transducer) (Correct answer)
- Bidirectional
- Away from the transducer
- Variable depending on patient position
Correct answer: Antegrade (towards the transducer)
When insonating through the transtemporal window for a TCD exam, the ultrasound beam is typically aimed superiorly and slightly anteriorly. The middle cerebral artery (MCA) courses laterally from the circle of Willis, so its blood flow is directed towards the transducer, resulting in an antegrade or positive Doppler shift.
Question 30: Lateral resolution in ultrasound is best improved by:
- Focusing the beam at the depth of interest (Correct answer)
- Increasing the pulse repetition frequency
- Lowering the transducer frequency
- Increasing pulse duration
Correct answer: Focusing the beam at the depth of interest
Lateral resolution equals beam width, which is minimized at the focal zone; therefore focusing the beam at the target depth optimizes lateral resolution.
Question 31: After carotid artery stenting, a patient is found to have a PSV of 340 cm/s within the stent at a 12-month follow-up. The most appropriate classification and action is:
- Normal post-stent velocity; reassure and discharge
- Stent fracture artifact; repeat with different transducer
- Moderate stenosis; continue standard annual surveillance
- Severe in-stent restenosis (>70%); refer for catheter angiography to consider re-intervention (Correct answer)
Correct answer: Severe in-stent restenosis (>70%); refer for catheter angiography to consider re-intervention
ICA PSV >300 cm/s within a carotid stent meets the duplex threshold for severe restenosis (>70%), requiring angiographic confirmation and consideration of re-intervention.
Question 32: In renal artery duplex assessment, which indirect parameter best reflects significant proximal renal artery stenosis when direct visualization is limited?
- Renal cortex thickness
- Renal acceleration time and acceleration index (Correct answer)
- Peak systolic velocity in the arcuate arteries
- Renal volume index
Correct answer: Renal acceleration time and acceleration index
Acceleration time >70–100 ms and acceleration index <300 cm/s² in intrarenal segmental arteries are indirect indicators of significant proximal renal artery stenosis.
Question 33: In a patient with an infrarenal AAA being followed by duplex surveillance, which measurement is the standard for monitoring aneurysm growth?
- Maximum transverse diameter of the lumen only
- Inner lumen diameter excluding mural thrombus
- Maximum outer-wall-to-outer-wall anteroposterior diameter (Correct answer)
- Aneurysm length from neck to bifurcation
Correct answer: Maximum outer-wall-to-outer-wall anteroposterior diameter
The maximum outer-wall AP diameter is the standard measurement for AAA surveillance, as it captures the true risk of rupture regardless of thrombus.
Question 34: What does the term 'post-thrombotic syndrome' describe in the context of peripheral venous disease?
- Venous malformation detected after thrombophlebitis
- Acute pulmonary embolism following DVT
- Chronic venous hypertension and symptoms resulting from prior DVT damage to valves and vein walls (Correct answer)
- Recurrent DVT in the same limb
Correct answer: Chronic venous hypertension and symptoms resulting from prior DVT damage to valves and vein walls
Post-thrombotic syndrome results from valve destruction and chronic venous hypertension following DVT, causing pain, edema, and skin changes.
Question 35: How often must RVTs renew their certification?
- Every 10 years
- Every 5 years (Correct answer)
- Every 2 years
- Every 3 years
Correct answer: Every 5 years
RVTs must renew their certification every 5 years. This periodic renewal ensures that certified professionals consistently meet the standards set by the American Registry for Diagnostic Medical Sonography (ARDMS). It mandates ongoing engagement with professional development and continuing education to maintain active status.
Question 36: The acoustic impedance of a medium is determined by:
- Pulse duration and duty factor
- Density and propagation speed (Correct answer)
- Attenuation coefficient and depth
- Frequency and wavelength
Correct answer: Density and propagation speed
Acoustic impedance (Z) equals the product of the medium's density (ρ) and the speed of sound (c) in that medium: Z = ρc.
Question 37: What is the primary purpose of performing a celiac axis duplex examination during both inspiration and expiration?
- To distinguish extrinsic compression by the median arcuate ligament from intrinsic atherosclerotic stenosis (Correct answer)
- To maximize Doppler angle correction accuracy
- To differentiate celiac artery from superior mesenteric artery origin
- To evaluate postprandial hemodynamic response of the celiac axis
Correct answer: To distinguish extrinsic compression by the median arcuate ligament from intrinsic atherosclerotic stenosis
Median arcuate ligament compression of the celiac artery typically worsens during expiration and improves with inspiration, distinguishing it from fixed atherosclerotic disease.
Question 38: A 68-year-old male presents with episodes of dizziness, vertigo, and bilateral visual disturbances. A carotid duplex ultrasound reveals antegrade flow in both internal carotid arteries and the right vertebral artery. However, the left vertebral artery demonstrates sustained retrograde flow. What is the most likely diagnosis?
- Left subclavian steal syndrome (Correct answer)
- Bilateral carotid artery stenosis
- Right subclavian steal syndrome
- Vertebrobasilar insufficiency
Correct answer: Left subclavian steal syndrome
Subclavian steal syndrome is characterized by the reversal of blood flow in the vertebral artery on the same side as a significant stenosis or occlusion of the proximal subclavian artery. The retrograde flow in the left vertebral artery indicates that blood is being 'stolen' from the posterior circulation to supply the left arm, which is diagnostic of left subclavian steal syndrome.
Question 39: A registered vascular technologist relocates and joins a new vascular lab. Which statement about their ARDMS credential is correct?
- The technologist must retake Part II of the RVT exam in the new state
- The credential is suspended until the employer notifies ARDMS
- The ARDMS credential is national and remains valid at the new facility (Correct answer)
- The credential must be transferred to the new state's registry
Correct answer: The ARDMS credential is national and remains valid at the new facility
ARDMS credentials are nationally recognized and are not state-specific, so relocation does not affect validity.
Question 40: A patient presents with left lower extremity swelling and pain. Duplex ultrasound reveals compression of the left common iliac vein by the overlying right common iliac artery. This finding is most consistent with:
- Paget-Schroetter Syndrome
- Phlegmasia Cerulea Dolens
- May-Thurner Syndrome (Correct answer)
- Klippel-Trenaunay Syndrome
Correct answer: May-Thurner Syndrome
May-Thurner Syndrome (MTS), also known as iliac vein compression syndrome, is a condition where the left common iliac vein is compressed by the right common iliac artery against the lumbar spine. This compression can impede venous outflow from the left leg, leading to swelling, pain, and an increased risk of DVT.
Question 41: A patient has an ABI of 0.55 at rest. After a standard treadmill test, the patient stops at 2 minutes due to bilateral calf pain and the ankle pressure is unobtainable. The MOST likely diagnosis is:
- Severe bilateral lower extremity PAD with exercise-limiting claudication (Correct answer)
- Psychogenic pain with normal arterial physiology
- Mild peripheral arterial disease with anxiety-related stopping
- Venous claudication due to deep vein obstruction
Correct answer: Severe bilateral lower extremity PAD with exercise-limiting claudication
An already low resting ABI (0.55) with inability to complete treadmill testing and unobtainable post-exercise pressures indicates severe hemodynamically significant bilateral PAD.
Question 42: When evaluating AV fistula maturation readiness for cannulation ('rule of 6s'), which duplex criterion best supports adequate maturation?
- Vein pulsatility index <1.0 and diameter ≥4 mm
- Outflow vein diameter ≥6 mm, depth ≤6 mm below skin surface, and access flow ≥600 mL/min (Correct answer)
- Access flow ≥200 mL/min with any vein diameter
- Outflow vein diameter ≥2 mm and depth ≤1 cm below skin surface
Correct answer: Outflow vein diameter ≥6 mm, depth ≤6 mm below skin surface, and access flow ≥600 mL/min
The 'rule of 6s' for fistula maturation states the vein should be ≥6 mm in diameter, ≤6 mm deep (accessible for cannulation), and achieve ≥600 mL/min flow, ideally within 6 weeks. Duplex ultrasound is the primary tool used to objectively assess each of these criteria before clinical cannulation begins.
Question 43: Which best describes the role of the Society for Vascular Ultrasound (SVU) in the RVT continuing education ecosystem?
- SVU provides educational resources, accredited CME, and advocacy for vascular sonographers (Correct answer)
- SVU sets federal standards for vascular laboratory staffing ratios
- SVU issues its own competing credential that replaces the RVT
- SVU administers the RVT exam on behalf of ARDMS
Correct answer: SVU provides educational resources, accredited CME, and advocacy for vascular sonographers
SVU supports RVT credential holders through educational programming, accredited CME opportunities, and professional advocacy rather than credentialing.
Question 44: Which Doppler waveform pattern is characteristic of a low-resistance vascular bed, such as the internal carotid artery or renal artery?
- High systolic peak with absent diastolic flow
- Triphasic pattern with diastolic reversal
- Sharp systolic upstroke with complete diastolic cessation
- Continuous forward flow throughout diastole with broad systolic peak (Correct answer)
Correct answer: Continuous forward flow throughout diastole with broad systolic peak
Organs with continuous metabolic demand (brain, kidneys) maintain low resistance, producing persistent forward diastolic flow on Doppler.
Question 45: When documenting a carotid duplex examination, which finding most accurately represents a 70–99% internal carotid artery stenosis by the Society of Radiologists in Ultrasound (SRU) criteria?
- ICA PSV 100–124 cm/s with no plaque
- ICA PSV ≥ 230 cm/s with ICA/CCA PSV ratio ≥ 4.0 (Correct answer)
- ICA PSV 125–229 cm/s with ICA/CCA ratio < 2.0
- ICA end-diastolic velocity < 40 cm/s with visible plaque
Correct answer: ICA PSV ≥ 230 cm/s with ICA/CCA PSV ratio ≥ 4.0
The SRU consensus criteria define ≥70% ICA stenosis as ICA PSV ≥230 cm/s AND an ICA/CCA PSV ratio ≥4.0, often accompanied by ICA EDV ≥100 cm/s. Using both absolute velocity and the ratio improves accuracy and accounts for hemodynamic variability between patients.
Question 46: In transcranial Doppler, the middle cerebral artery (MCA) is typically insonated through which window at a depth of 45-65 mm?
- Suboccipital (transforaminal) window
- Transtemporal window (Correct answer)
- Submandibular window
- Transorbital window
Correct answer: Transtemporal window
The transtemporal window, located above the zygomatic arch near the temporal bone, allows insonation of the MCA at depths of 45-65 mm.
Question 47: Lateral resolution in ultrasound imaging is best at the:
- Focal zone of the transducer (Correct answer)
- Depth equal to half the wavelength
- Far field (Fraunhofer zone) at maximum depth
- Near field (Fresnel zone) directly below the transducer face
Correct answer: Focal zone of the transducer
Lateral resolution (ability to separate two side-by-side structures) is optimal at the focal zone where the beam is narrowest, and degrades in both the near and far fields as the beam diverges.
Question 48: Acoustic impedance (Z) of a tissue is determined by:
- The product of tissue density and the speed of sound in that tissue (Correct answer)
- The depth of the structure divided by the time of flight
- The ratio of transmitted frequency to reflected frequency
- The attenuation coefficient multiplied by path length
Correct answer: The product of tissue density and the speed of sound in that tissue
Acoustic impedance Z = ρ × c, where ρ is tissue density and c is the propagation speed of sound; mismatches at tissue interfaces determine the magnitude of reflection.
Question 49: In the evaluation of a renal transplant by duplex ultrasound, which finding raises the concern for renal vein thrombosis?
- Acceleration time greater than 70 ms in segmental arteries
- Absent venous signal in interlobar veins only
- Reversed diastolic flow (below baseline) in the intrarenal arteries (Correct answer)
- Elevated PSV in the main renal artery exceeding 200 cm/s
Correct answer: Reversed diastolic flow (below baseline) in the intrarenal arteries
Renal vein thrombosis markedly raises downstream venous pressure, causing reversal of diastolic arterial flow as a characteristic duplex sign.
Question 50: What does the 'R' in RVT signify in the context of the credential?
- Registered (Correct answer)
- Recognized
- Reviewed
- Radiologic
Correct answer: Registered
The 'R' in RVT stands for 'Registered,' indicating the individual has met ARDMS examination and eligibility standards.
Question 51: A patient undergoes a segmental pressure study. The following resting systolic pressures are obtained: Right Brachial: 150 mmHg, Right High Thigh: 130 mmHg, Right Above Knee: 125 mmHg, Right Below Knee: 120 mmHg, Right Ankle: 115 mmHg. Which of the following is the most likely location of significant arterial disease?
- Right iliofemoral arteries (Correct answer)
- Right tibial arteries
- Right popliteal artery
- No significant disease is present
Correct answer: Right iliofemoral arteries
A pressure drop of more than 20-30 mmHg between adjacent segments is considered significant for arterial occlusive disease. In this case, there is a 20 mmHg pressure drop between the brachial pressure (inflow) and the high thigh, indicating a likely stenosis in the aortoiliac or common femoral artery segment. The subsequent drops down the leg are less than 20 mmHg.
Question 52: Which organization offers the Registered Vascular Technologist (RVT) certification?
- National Healthcareer Association (NHA)
- American Registry of Radiologic Technologists (ARRT)
- Board of Registered Vascular Technologists (BRVT)
- American Registry for Diagnostic Medical Sonography (ARDMS) (Correct answer)
Correct answer: American Registry for Diagnostic Medical Sonography (ARDMS)
The American Registry for Diagnostic Medical Sonography (ARDMS) is the internationally recognized credentialing body that offers the Registered Vascular Technologist (RVT) certification. ARDMS sets the standards for competence in sonography and provides various certifications, including the RVT, to ensure qualified professionals in the field.
Question 53: In patients with bilateral high-grade ICA stenosis, the CCA waveform may demonstrate which compensatory change?
- No change from normal
- Reversal of systolic flow in the CCA
- Increased resistance with absent diastolic flow
- Reduced resistance pattern with elevated diastolic flow bilaterally (Correct answer)
Correct answer: Reduced resistance pattern with elevated diastolic flow bilaterally
Bilateral severe ICA disease causes the brain to maximally vasodilate distal resistance vessels, creating a low-resistance high-diastolic pattern in both CCAs.
Question 54: Which intraoperative duplex finding after infrainguinal bypass graft creation most likely warrants immediate surgical revision?
- Graft diameter slightly smaller than the native tibial artery
- Phasic (triphasic) flow pattern throughout the graft body
- Mild color-flow turbulence immediately distal to the proximal anastomosis
- Focal peak systolic velocity ratio greater than 3:1 across an anastomotic segment (Correct answer)
Correct answer: Focal peak systolic velocity ratio greater than 3:1 across an anastomotic segment
A PSV ratio >3:1 across a focal segment indicates a hemodynamically significant stenosis (≥75% diameter reduction). When found intraoperatively before the wound is closed, it signals a technical defect — suture narrowing, intimal flap, or kinking — that should be corrected immediately to prevent early graft failure.
Question 55: During an EVAR follow-up ultrasound, flow is detected originating from patent lumbar arteries that perfuses the aneurysm sac in a retrograde fashion. This finding is the classic presentation of which type of endoleak?
- Type II (Correct answer)
- Type IV
- Type I
- Type III
Correct answer: Type II
A Type II endoleak is defined as retrograde flow into the aneurysm sac from collateral branch vessels, most commonly the lumbar arteries or the inferior mesenteric artery. [26, 28, 29] Type I is a leak at the graft attachment sites, Type III is a graft defect, and Type IV is due to graft porosity. [27]
Question 56: An abdominal duplex exam shows a color Doppler 'yin-yang' sign with a swirling pattern adjacent to the aorta. This is most consistent with:
- Aortic pseudoaneurysm with a communicating neck (Correct answer)
- Retroperitoneal hematoma compressing the aorta
- Abdominal aortic aneurysm with laminar thrombus
- Aortic dissection with a false lumen
Correct answer: Aortic pseudoaneurysm with a communicating neck
The yin-yang sign represents bidirectional swirling flow within a pseudoaneurysm sac connected to the vessel through a narrow neck.
Question 57: The peak systolic velocity ratio (PSVR) used to grade arterial stenosis severity is calculated as:
- PSV at the stenosis divided by PSV measured distal to the stenosis
- PSV at the stenosis divided by PSV in the adjacent proximal normal arterial segment (Correct answer)
- End-diastolic velocity divided by peak systolic velocity at the stenosis
- Mean velocity at the stenosis divided by resistive index
Correct answer: PSV at the stenosis divided by PSV in the adjacent proximal normal arterial segment
The PSVR compares the elevated velocity at the stenosis to the velocity in the proximal normal (pre-stenotic) segment. This ratio corrects for patient-to-patient variation in cardiac output and overall flow state, making it a more reliable indicator of stenosis severity than an absolute PSV value alone.
Question 58: An RVT working as a clinical educator for a sonography program is fulfilling which career role?
- Per-diem technologist
- Research coordinator
- Applications specialist
- Allied health faculty/instructor (Correct answer)
Correct answer: Allied health faculty/instructor
Teaching in a sonography program places the RVT in an allied health faculty role, where their clinical expertise is transferred to future technologists.
Question 59: Which vessel is most commonly responsible for a watershed infarct between the MCA and ACA territories?
- Internal carotid artery stenosis (Correct answer)
- Posterior communicating artery aneurysm
- Vertebral artery occlusion
- Basilar artery thrombosis
Correct answer: Internal carotid artery stenosis
Severe ICA stenosis reduces perfusion pressure, making the border-zone watershed region between MCA and ACA territories vulnerable to ischemia.
Question 60: The Lindegaard ratio is used in TCD to distinguish cerebral vasospasm from hyperemia after subarachnoid hemorrhage. Which vessels are compared to calculate this ratio?
- Basilar artery to ipsilateral vertebral artery
- MCA to ipsilateral anterior cerebral artery
- Anterior cerebral artery to posterior cerebral artery
- Middle cerebral artery to ipsilateral extracranial internal carotid artery (Correct answer)
Correct answer: Middle cerebral artery to ipsilateral extracranial internal carotid artery
The Lindegaard ratio = MCA mean velocity ÷ ipsilateral extracranial ICA mean velocity. In vasospasm the intracranial vessels narrow while the extracranial ICA is unaffected, yielding a ratio >3 (severe spasm >6). In hyperemia, both MCA and ICA velocities rise proportionally, keeping the ratio <3.
Question 61: Pre-operative vein mapping for AV fistula creation shows a cephalic vein with a diameter of 1.6 mm that does not distend when a tourniquet is applied. This finding indicates the vein is:
- Unsuitable — the diameter is below the 2 mm threshold and the vein lacks distensibility (Correct answer)
- Borderline — a repeat mapping after hand exercises should be performed
- Adequate — any vein ≥1.5 mm is acceptable for fistula creation
- Suitable if the patient maintains adequate hydration before surgery
Correct answer: Unsuitable — the diameter is below the 2 mm threshold and the vein lacks distensibility
Guidelines recommend a minimum cephalic vein diameter of ≥2 mm (with many centers preferring ≥2.5 mm) for successful fistula maturation. Poor distensibility indicates a sclerosed or calcified vein that will not enlarge adequately after arterialization, predicting fistula failure.
Question 62: Aliasing in color flow Doppler imaging appears as:
- A uniform increase in red signal intensity throughout the vessel
- Acoustic shadowing distal to a calcified plaque
- An abrupt color reversal in the center of a high-velocity jet (Correct answer)
- A complete absence of color within the vessel lumen
Correct answer: An abrupt color reversal in the center of a high-velocity jet
When peak Doppler shift exceeds the Nyquist limit, aliasing causes the color to wrap around and display the opposite color (e.g., red becomes blue) at the site of high velocity.
Question 63: When performing a phantom test on a Doppler ultrasound system, which parameter is most critical to assess flow sensitivity?
- Spatial resolution in the near field
- Acoustic output power in mW/cm²
- Minimum detectable velocity using a flow phantom (Correct answer)
- Depth penetration at 15 cm
Correct answer: Minimum detectable velocity using a flow phantom
Minimum detectable velocity using a certified flow phantom directly measures Doppler sensitivity, which is essential for detecting low-flow states in peripheral vessels.
Question 64: A vascular lab's Doppler velocity measurements drift 15% higher than baseline over six months. The MOST likely cause is:
- Transducer crystal degradation changing frequency output (Correct answer)
- Software algorithm update
- Technologist technique variability
- Patient body habitus changes
Correct answer: Transducer crystal degradation changing frequency output
Piezoelectric crystal aging or damage shifts the actual transmitted frequency, causing systematic velocity calculation errors because the Doppler equation uses the known center frequency.
Question 65: During carotid duplex scanning, color aliasing within a stenotic segment indicates that the local flow velocity:
- Is bidirectional due to turbulence only
- Has dropped below the Nyquist limit
- Represents venous contamination
- Has exceeded the Nyquist limit (PRF/2) (Correct answer)
Correct answer: Has exceeded the Nyquist limit (PRF/2)
Color aliasing occurs when velocities exceed the Nyquist limit (half the pulse repetition frequency), causing color wrap-around and indicating high-velocity stenotic flow.
Question 66: Which federal legislation most directly affects RVT employment opportunities in hospital outpatient departments?
- Affordable Care Act (ACA) expansion of coverage (Correct answer)
- HIPAA Privacy Rule
- Clinical Laboratory Improvement Amendments (CLIA)
- Americans with Disabilities Act (ADA)
Correct answer: Affordable Care Act (ACA) expansion of coverage
The ACA expanded insurance coverage to millions of Americans, increasing demand for diagnostic vascular services and consequently RVT job opportunities in outpatient settings.
Question 67: A patient undergoing reactive hyperemia testing shows an ABI that falls from 1.0 to 0.55 after 3 minutes of cuff occlusion and takes 5 minutes to return to baseline. What does this indicate?
- Sympathetic nervous system dysfunction
- Venous obstruction mimicking arterial disease
- Hemodynamically significant arterial disease (Correct answer)
- Normal arterial response to ischemic stress
Correct answer: Hemodynamically significant arterial disease
In reactive hyperemia, an ABI drop >15-20% with slow recovery indicates significant arterial occlusive disease unable to meet increased metabolic demand.
Question 68: What does a resistive index (RI) greater than 0.80 in the renal parenchymal vessels suggest when evaluating for renovascular hypertension?
- Normal renal vascular resistance in an elderly patient
- High-grade renal artery stenosis requiring urgent intervention
- Intrinsic renal parenchymal disease that may limit benefit from revascularization (Correct answer)
- Acute renal vein thrombosis
Correct answer: Intrinsic renal parenchymal disease that may limit benefit from revascularization
An RI >0.80 suggests elevated intrinsic renal vascular resistance, indicating parenchymal disease that often predicts poor response to renal artery stenting.
Question 69: During a lower extremity venous duplex examination for suspected deep vein thrombosis (DVT), the primary diagnostic criterion is:
- Visualization of echogenic material within the vein lumen.
- Lack of complete coaptation of the vein walls with transducer pressure. (Correct answer)
- The presence of a continuous, non-phasic waveform in the common femoral vein.
- Demonstration of reversed flow with color Doppler.
Correct answer: Lack of complete coaptation of the vein walls with transducer pressure.
The most reliable and primary criterion for diagnosing a deep vein thrombosis (DVT) with ultrasound is the inability to fully compress the vein walls together with gentle transducer pressure. While visualization of echogenic material is a supporting finding, and Doppler abnormalities can suggest obstruction, the failure to coapt is the definitive sign of an intraluminal thrombus.
Question 70: Photoplethysmography (PPG) is used to assess digital perfusion. What does a flattened, obstructive waveform on digital PPG indicate?
- Venous hypertension in the digit
- Vasospasm that will resolve with warming
- Significant arterial obstruction reducing pulsatile flow to the digit (Correct answer)
- Normal variant in elderly patients
Correct answer: Significant arterial obstruction reducing pulsatile flow to the digit
A flat or nearly absent PPG waveform indicates severely reduced or absent pulsatile arterial inflow to the digit, consistent with significant obstruction or critical ischemia.
Question 71: In the RVT exam context, what is the purpose of performing a 'steal syndrome' evaluation of the subclavian artery?
- To assess carotid bifurcation plaque morphology
- To detect renal artery stenosis via retrograde flow
- To identify reversed vertebral artery flow due to proximal subclavian stenosis (Correct answer)
- To measure brachial artery reactivity after occlusion
Correct answer: To identify reversed vertebral artery flow due to proximal subclavian stenosis
Subclavian steal syndrome is characterized by reversal of vertebral artery flow ipsilateral to a proximal subclavian stenosis, diverting blood from the posterior circulation.
Question 72: A 70-year-old male presents with sudden, severe 'tearing' chest pain radiating to his back. An abdominal ultrasound visualizes a linear, echogenic structure fluttering within the aortic lumen, separating it into two distinct channels. What is this classic finding called?
- Intimal flap (Correct answer)
- Atherosclerotic plaque
- Mural thrombus
- Reverberation artifact
Correct answer: Intimal flap
The clinical presentation is highly suggestive of an aortic dissection. The sonographic finding of a mobile, linear structure within the lumen that separates a true lumen from a false lumen is the characteristic intimal flap, which represents the torn intimal layer of the vessel wall.
Question 73: Under ARDMS policy, which of the following is grounds for denial of an RVT credential application?
- Applying more than 6 months before program graduation
- Conviction of a felony or misdemeanor involving moral turpitude (Correct answer)
- Holding credentials from a non-ARDMS organization only
- Working part-time rather than full-time in vascular ultrasound
Correct answer: Conviction of a felony or misdemeanor involving moral turpitude
ARDMS may deny, suspend, or revoke credentials based on criminal convictions, particularly those involving moral turpitude, as outlined in their eligibility policies.
Question 74: What is the primary advantage of pulse volume recordings (PVR) over segmental limb pressures in patients with calcified vessels?
- PVR is more sensitive for detecting mild disease
- PVR assesses volume changes rather than compressibility, making it reliable despite vessel calcification (Correct answer)
- PVR can identify specific anatomic stenosis locations more accurately
- PVR provides direct measurement of arterial pressure
Correct answer: PVR assesses volume changes rather than compressibility, making it reliable despite vessel calcification
PVR measures limb volume changes with each cardiac cycle using air plethysmography, which is not affected by vessel wall stiffness or calcification, unlike pressure-based measurements.
Question 75: What is the preferred ultrasound-guided intervention for an iatrogenic femoral pseudoaneurysm that fails compression therapy?
- Balloon angioplasty of the puncture site
- Surgical ligation under general anesthesia
- Ultrasound-guided thrombin injection into the pseudoaneurysm sac (Correct answer)
- Elastic compression bandaging for 72 hours
Correct answer: Ultrasound-guided thrombin injection into the pseudoaneurysm sac
Ultrasound-guided thrombin injection is the first-line treatment for pseudoaneurysms that do not respond to compression. A small volume of thrombin (100–500 units) is injected directly into the sac under real-time imaging, inducing rapid thrombosis while the neck is monitored to prevent inadvertent arterial embolization.
Question 76: Which statement CORRECTLY describes the relationship between ankle-brachial index (ABI) values and cardiovascular risk?
- ABI values are predictive of limb outcomes only, not cardiovascular events
- Only low ABI values (<0.9) are associated with increased cardiovascular mortality
- ABI >1.0 is always protective against cardiovascular events
- Both low ABI (<0.9) and high ABI (>1.3) are independently associated with increased cardiovascular mortality (Correct answer)
Correct answer: Both low ABI (<0.9) and high ABI (>1.3) are independently associated with increased cardiovascular mortality
Both low ABI (reflecting atherosclerosis) and high ABI (reflecting arterial stiffness from calcification) are independently associated with increased cardiovascular morbidity and mortality.
Question 77: Ultrasound-guided compression repair of a femoral pseudoaneurysm is MOST likely to fail or be contraindicated when the patient is:
- Post-diagnostic (non-therapeutic) catheterization
- Female with a body mass index under 25
- Undergoing anticoagulation therapy (Correct answer)
- Older than 70 years of age
Correct answer: Undergoing anticoagulation therapy
Anticoagulation significantly impairs the ability to thrombose the pseudoaneurysm sac during compression, making the procedure much less effective and requiring prolonged compression times. In anticoagulated patients, ultrasound-guided thrombin injection is the preferred alternative because it does not depend on the coagulation cascade.
Question 78: Which of the following best describes the duty factor in pulsed ultrasound?
- The number of pulses emitted per second
- The ratio of pulse duration to the pulse repetition period (Correct answer)
- The ratio of listening time to transmit time
- The total acoustic power divided by beam area
Correct answer: The ratio of pulse duration to the pulse repetition period
Duty factor is the fraction of time the transducer is actively transmitting, calculated as pulse duration divided by the pulse repetition period.
Question 79: Carotid body tumors (paragangliomas) at the bifurcation characteristically displace which two vessels on duplex ultrasound?
- CCA and ECA are splayed apart
- ICA and ECA are splayed apart (lyre sign) (Correct answer)
- CCA and vertebral artery are compressed together
- ICA and vertebral artery are displaced medially
Correct answer: ICA and ECA are splayed apart (lyre sign)
The 'lyre sign' describes widening of the angle between the ICA and ECA caused by a hypervascular carotid body tumor seated at the bifurcation.
Question 80: Which anatomical variant describes the absence of one segment of the Circle of Willis, making a patient more vulnerable to stroke if a feeding vessel is occluded?
- Fenestrated basilar artery
- Persistent trigeminal artery
- Aplastic or hypoplastic communicating artery (Correct answer)
- Duplicated MCA
Correct answer: Aplastic or hypoplastic communicating artery
Aplasia or hypoplasia of communicating arteries (ACoA or PCoA) limits collateral flow reserve, increasing stroke risk when a major feeding vessel is compromised.
Question 81: Under the principle of universal precautions, how should vascular laboratory staff treat ALL patient blood and body fluids?
- As requiring only standard gloves, with no additional PPE
- As potentially infectious regardless of the patient's known diagnosis (Correct answer)
- As non-infectious unless the patient tests positive for HIV or hepatitis
- As infectious only during invasive procedures
Correct answer: As potentially infectious regardless of the patient's known diagnosis
Universal precautions mandate treating every patient's blood and body fluids as potentially infectious to protect staff from undiagnosed or unreported bloodborne pathogens.
Question 82: Which condition can produce a falsely HIGH ABI, potentially masking severe peripheral arterial disease?
- Severe anemia
- Cardiac tamponade
- Acute deep vein thrombosis
- Medial arterial calcification (Mönckeberg sclerosis) (Correct answer)
Correct answer: Medial arterial calcification (Mönckeberg sclerosis)
Medial calcification renders vessels incompressible, requiring supra-systolic cuff pressures that never fully occlude the artery, resulting in ABI values >1.3 despite significant disease.
Question 83: A patient with a forearm AV fistula reports pain, coldness, and numbness in the hand that worsens during dialysis. Duplex reveals reversal of flow in the radial artery distal to the fistula anastomosis. This presentation is MOST consistent with:
- Arterial inflow stenosis proximal to the anastomosis
- Dialysis-associated steal syndrome (Correct answer)
- Venous outflow obstruction causing elevated access pressures
- Central venous stenosis causing venous hypertension
Correct answer: Dialysis-associated steal syndrome
Steal syndrome occurs when the low-resistance AV fistula 'steals' blood from the distal limb. The reversed (retrograde) flow in the radial artery distal to the anastomosis is the pathognomonic duplex finding — blood that should perfuse the hand is instead diverted into the fistula, causing ischemic symptoms that worsen during high-flow dialysis sessions.
Question 84: Which hand hygiene product is considered MOST effective for reducing transmission of Clostridium difficile spores in a vascular laboratory setting?
- Chlorhexidine gluconate foam
- Plain soap and water with thorough rinsing (Correct answer)
- Alcohol-based hand rub (ABHR)
- Iodine-based antiseptic scrub
Correct answer: Plain soap and water with thorough rinsing
Alcohol-based hand rubs do not kill C. difficile spores; plain soap and water physically removes spores from the hands and is the recommended approach for C. diff prevention.
Question 85: Which Doppler parameter is most sensitive for detecting a hemodynamically significant stenosis when peak systolic velocity is limited by low cardiac output?
- Peak systolic velocity alone
- ICA-to-CCA peak systolic velocity ratio (Correct answer)
- Resistive index of the CCA
- End-diastolic velocity alone
Correct answer: ICA-to-CCA peak systolic velocity ratio
The ICA/CCA PSV ratio normalizes for cardiac output, making it more reliable than absolute velocity in low-flow states; a ratio >4.0 indicates ≥70% stenosis.
Question 86: Carotid artery stenting (CAS) post-procedure surveillance with duplex ultrasound uses different velocity thresholds than native vessel criteria because stents:
- Reduce wall compliance and increase velocities, requiring higher threshold cutoffs (Correct answer)
- Only affect diastolic velocities
- Have no effect on Doppler velocities
- Increase wall compliance and decrease velocities
Correct answer: Reduce wall compliance and increase velocities, requiring higher threshold cutoffs
Stents reduce arterial wall compliance and produce intrinsically higher peak velocities, necessitating higher PSV thresholds (e.g., >300-450 cm/s for ≥50% in-stent restenosis) compared to native vessel criteria.
Question 87: Which of the following best describes a 'primary-source verification' in the context of RVT credentialing?
- A background check performed by a local police department
- Confirmation of credential status directly from ARDMS, rather than from the credential holder (Correct answer)
- A copy of the candidate's academic transcript
- A letter of recommendation from a supervisor
Correct answer: Confirmation of credential status directly from ARDMS, rather than from the credential holder
Primary-source verification means an employer or institution confirms an RVT's credential status directly with ARDMS, the issuing body.
Question 88: In the context of vascular laboratory QA, what is the purpose of a 'correlation study'?
- To assess whether equipment cleaning reduces infection rates
- To calculate inter-rater agreement between two sonographers scanning the same patient consecutively
- To compare the lab's duplex findings with those from another imaging modality to validate diagnostic accuracy (Correct answer)
- To measure Doppler angle reproducibility across technologists
Correct answer: To compare the lab's duplex findings with those from another imaging modality to validate diagnostic accuracy
A correlation study compares duplex ultrasound findings to a reference standard such as CTA, MRA, or angiography to verify the lab's diagnostic thresholds are clinically valid.
Question 89: When assessing the portal vein by duplex, which finding is most consistent with portal hypertension?
- Hepatopetal flow with velocity less than 16 cm/s and increased vessel diameter
- Hepatofugal flow reversal in the main portal vein (Correct answer)
- Phasic flow variation with respiration greater than 30%
- High-velocity turbulent flow exceeding 100 cm/s
Correct answer: Hepatofugal flow reversal in the main portal vein
Hepatofugal (away from the liver) flow reversal in the main portal vein is a hallmark finding of significant portal hypertension.
Question 90: An RVT credential holder retires from clinical practice. What happens to their credential?
- It is immediately revoked upon retirement
- It is automatically transferred to an honorary status
- It will lapse at the next renewal deadline if CME and fees are not submitted (Correct answer)
- It remains active indefinitely at no cost
Correct answer: It will lapse at the next renewal deadline if CME and fees are not submitted
Credentials are maintained only if renewal requirements (CME credits and fees) are met; retirement does not grant automatic active or honorary status.
Question 91: In abdominal duplex scanning, the 'median arcuate ligament syndrome' most commonly affects which vessel?
- Inferior mesenteric artery
- Celiac artery (Correct answer)
- Superior mesenteric artery
- Right renal artery
Correct answer: Celiac artery
The median arcuate ligament of the diaphragm crosses anteriorly and may compress the celiac artery origin, causing extrinsic stenosis.
Question 92: An arteriovenous fistula (AVF) feeding artery typically demonstrates which hemodynamic pattern compared to the contralateral normal artery?
- Normal triphasic waveform with equivalent peak velocity
- Higher resistance with absent diastolic flow
- Reversed diastolic flow indicating steal phenomenon
- Lower resistance with increased diastolic flow and elevated peak systolic velocity (Correct answer)
Correct answer: Lower resistance with increased diastolic flow and elevated peak systolic velocity
The low-resistance shunt of an AVF draws continuous forward flow, causing high-volume, low-resistance flow in the feeding artery with elevated peak systolic and end-diastolic velocities.
Question 93: According to the widely accepted SRU (Society of Radiologists in Ultrasound) consensus criteria for grading internal carotid artery stenosis, which of the following findings is most consistent with a stenosis of 70% or greater?
- ICA/CCA PSV ratio of 1.5
- Peak Systolic Velocity (PSV) greater than 230 cm/s (Correct answer)
- Peak Systolic Velocity (PSV) of 125 cm/s
- End-Diastolic Velocity (EDV) of 30 cm/s
Correct answer: Peak Systolic Velocity (PSV) greater than 230 cm/s
The SRU consensus criteria use a Peak Systolic Velocity (PSV) of greater than 230 cm/s as a primary parameter to diagnose an internal carotid artery stenosis of 70% or greater, up to near occlusion. Additional parameters like an End-Diastolic Velocity (EDV) >100 cm/s and an ICA/CCA PSV ratio >4.0 are also used to confirm high-grade stenosis.
Question 94: When performing a renal artery duplex exam, the renal-to-aortic ratio (RAR) is calculated using which measurement?
- Renal artery PSV divided by aortic PSV (Correct answer)
- Renal parenchymal velocity divided by renal artery PSV
- Renal artery EDV divided by aortic EDV
- Renal artery diameter divided by aortic diameter
Correct answer: Renal artery PSV divided by aortic PSV
The RAR is calculated by dividing the highest renal artery PSV by the infrarenal aortic PSV; a ratio ≥3.5 indicates significant stenosis.
Question 95: A duplex ultrasound system combines which two imaging modalities?
- Power Doppler and contrast-enhanced ultrasound
- Continuous-wave Doppler and M-mode imaging
- Color Doppler and CT angiography
- B-mode (gray-scale) imaging and pulsed-wave Doppler (Correct answer)
Correct answer: B-mode (gray-scale) imaging and pulsed-wave Doppler
Duplex ultrasound integrates real-time B-mode imaging for anatomical visualization with pulsed-wave Doppler spectral analysis for hemodynamic assessment.
Question 96: Hollenhorst plaques seen on fundoscopic examination are cholesterol emboli originating most commonly from:
- Aortic arch thrombus only
- Cardiac valve vegetations
- Vertebrobasilar system
- Atherosclerotic plaque in the ipsilateral carotid artery (Correct answer)
Correct answer: Atherosclerotic plaque in the ipsilateral carotid artery
Hollenhorst plaques are refractile cholesterol crystals lodged in retinal arterioles, typically originating from ulcerated atherosclerotic plaque in the ipsilateral ICA.
Question 97: Which of the following describes the proper technique for performing compressions during a lower extremity venous DVT study?
- Use color Doppler to confirm coaptation at the groin, popliteal, and ankle.
- Apply pressure in the longitudinal plane every 5 cm.
- Apply compressions only to symptomatic areas.
- Compress the vein in the transverse plane every 1-2 cm. (Correct answer)
Correct answer: Compress the vein in the transverse plane every 1-2 cm.
The standard protocol for a lower extremity DVT evaluation involves applying direct pressure with the transducer in the transverse plane at intervals of 1-2 cm along the deep veins. This ensures that the entire length of the major deep veins is assessed for compressibility, as a thrombus can be focal.
Question 98: Which transducer design uses multiple elements fired in sequence to create a rectangular field of view?
- Curvilinear array
- Phased array
- Annular array
- Linear array (Correct answer)
Correct answer: Linear array
Linear array transducers fire elements sequentially across the footprint to produce a rectangular image with consistent width at all depths.
Question 99: In the context of arteriovenous fistula (AVF) surveillance, which Doppler finding is most consistent with significant stenosis at the venous anastomosis?
- Focal velocity elevation with post-stenotic turbulence and decreased access flow (Correct answer)
- Absence of color Doppler signal throughout the graft
- Increased access flow volume with low resistance
- Bidirectional flow at the needle cannulation sites
Correct answer: Focal velocity elevation with post-stenotic turbulence and decreased access flow
Stenosis at the venous anastomosis causes a focal velocity increase and downstream turbulence while reducing overall access flow volume.
Question 100: A patient with ascites, hepatomegaly, and abdominal pain is referred for an abdominal vascular duplex exam. Which of the following findings would be most consistent with a diagnosis of Budd-Chiari syndrome?
- Markedly elevated velocities (>400 cm/s) in the superior mesenteric artery.
- Absence of detectable flow or visualization of thrombus within the major hepatic veins. (Correct answer)
- A highly pulsatile, 'to-and-fro' waveform in the main portal vein.
- A patent Transjugular Intrahepatic Portosystemic Shunt (TIPS).
Correct answer: Absence of detectable flow or visualization of thrombus within the major hepatic veins.
Budd-Chiari syndrome is a condition defined by the obstruction of hepatic venous outflow. The primary diagnostic finding on duplex ultrasound is the direct evidence of this obstruction, such as thrombosis, stenosis, or complete absence of flow in one or more of the major hepatic veins. The other findings are related to different pathologies.
Question 101: Which waveform characteristic on PVR (pulse volume recording) is MOST consistent with proximal aortoiliac occlusive disease?
- Normal waveform at thigh with abnormal calf waveform
- Flat, broad waveform with absent dicrotic notch throughout the limb (Correct answer)
- Biphasic waveform at the ankle with triphasic at the thigh
- Peaked systolic upstroke with sharp dicrotic notch
Correct answer: Flat, broad waveform with absent dicrotic notch throughout the limb
Aortoiliac disease produces diffusely flattened, broadened PVR waveforms throughout the entire lower extremity due to inflow obstruction affecting all segments.
Question 102: Which condition causes bilateral vertebral artery flow reversal and is associated with syncope or posterior circulation TIA symptoms triggered by arm exercise?
- Bilateral vertebral artery dissection
- Bilateral subclavian steal syndrome (Correct answer)
- Bilateral vertebral artery stenosis
- Basilar artery occlusion
Correct answer: Bilateral subclavian steal syndrome
Bilateral subclavian steal causes bilateral retrograde vertebral flow as both upper extremities steal from the posterior circulation during exercise, precipitating symptoms.
Question 103: The carotid siphon refers to the S-shaped segment of the internal carotid artery located in the:
- Neck at the carotid bifurcation
- Parapharyngeal space
- Cavernous sinus within the skull base (Correct answer)
- Petrous temporal bone
Correct answer: Cavernous sinus within the skull base
The carotid siphon is the S-shaped intracranial portion of the ICA that courses through the cavernous sinus.
Question 104: When performing pulse volume recordings (PVRs), what is the standard cuff inflation pressure used to sense volume changes in the limb segment without occluding arterial inflow?
- 100 mmHg
- 65 mmHg (Correct answer)
- Slightly above systolic pressure
- 20 mmHg
Correct answer: 65 mmHg
For pulse volume recordings (PVRs), also known as air plethysmography, the cuffs are inflated to a pressure high enough to conform to the limb and detect volume changes, but low enough not to compress the arteries. A standard pressure of 60-65 mmHg is typically used for this purpose.
Question 105: While performing a spectral Doppler evaluation, a sonographer encounters aliasing. Which of the following adjustments is LEAST effective for correcting this artifact?
- Increasing the overall Doppler gain. (Correct answer)
- Increasing the Pulse Repetition Frequency (PRF).
- Switching to a lower frequency transducer.
- Shifting the baseline down.
Correct answer: Increasing the overall Doppler gain.
Aliasing occurs when the Doppler shift exceeds the Nyquist limit. Increasing the PRF (scale), shifting the baseline, and using a lower frequency transducer are all effective methods to correct for or reduce aliasing. Increasing the Doppler gain only amplifies the entire signal, including the artifact, and does not change the parameters that cause aliasing.
Question 106: In a patient with suspected catheter-associated upper extremity DVT, which vein is most commonly affected?
- Brachial vein
- Basilic vein
- Cephalic vein
- Axillary or subclavian vein at catheter tip location (Correct answer)
Correct answer: Axillary or subclavian vein at catheter tip location
Central venous catheters most commonly cause thrombosis at or near the catheter tip, typically in the axillary or subclavian vein.
Question 107: A vascular technologist transitioning to an industry role would most likely work for which type of company?
- Medical device or ultrasound equipment company (Correct answer)
- Health insurance brokerage
- Pharmaceutical manufacturer
- Dental supply distributor
Correct answer: Medical device or ultrasound equipment company
Medical device and ultrasound equipment companies frequently hire RVTs as clinical specialists or applications trainers because of their hands-on imaging expertise.
Question 108: Which venous segment is best examined with the patient in a prone position during a lower extremity venous exam?
- Common femoral vein
- Popliteal and tibial veins (Correct answer)
- Femoral vein at mid-thigh
- External iliac vein
Correct answer: Popliteal and tibial veins
The prone position provides optimal access to the popliteal fossa and calf veins, which are located posteriorly.
Question 109: A patient with subarachnoid hemorrhage has TCD MCA mean flow velocities of 190 cm/s bilaterally on day 7 post-bleed. What does this MOST likely indicate?
- Bilateral MCA occlusion
- A normal post-hemorrhage hyperemic response
- Elevated intracranial pressure with preserved autoregulation
- Cerebral vasospasm requiring clinical attention (Correct answer)
Correct answer: Cerebral vasospasm requiring clinical attention
TCD mean velocities >120 cm/s in the MCA after SAH are consistent with vasospasm, and velocities >200 cm/s indicate severe spasm. Peak vasospasm typically occurs days 5–14 post-SAH. Early TCD detection allows intervention (hemodynamic augmentation, nimodipine, angioplasty) before clinical deficits appear.
Question 110: The normal intima-media thickness (IMT) of the common carotid artery in adults under 50 years is generally accepted as less than:
- 1.5 mm
- 0.9 mm (Correct answer)
- 0.5 mm
- 1.2 mm
Correct answer: 0.9 mm
An IMT of less than 0.9 mm is generally considered normal in adults, while values ≥1.0 mm suggest subclinical atherosclerosis.
Question 111: What is required to maintain RVT certification?
- Completing CME credits (Correct answer)
- Renewing state licenses annually
- Participating in workshops every year
- Obtaining additional certifications
Correct answer: Completing CME credits
To maintain RVT certification, registered vascular technologists must complete Continuing Medical Education (CME) credits. This requirement ensures that professionals stay current with the latest advancements, techniques, and best practices in vascular technology. It demonstrates a commitment to lifelong learning and helps maintain high standards of patient care.
Question 112: An RVT candidate completes an accredited 2-year vascular technology program but has not yet graduated. Can they apply to sit the ARDMS exam?
- No, official graduation and transcript submission are required before any application is accepted
- No, only physicians may apply before completing formal training
- Yes, they may apply as a final-year student under ARDMS's graduate eligibility rule (Correct answer)
- Yes, any enrollment in a health program qualifies immediately
Correct answer: Yes, they may apply as a final-year student under ARDMS's graduate eligibility rule
ARDMS allows final-year students in accredited programs to apply under a graduate eligibility window before official graduation.
Question 113: Which of the following vascular pathologies is characterized by a non-atherosclerotic, non-inflammatory process that causes abnormal cell growth in the arterial wall, often leading to a 'string of beads' appearance on angiography?
- Fibromuscular dysplasia (FMD) (Correct answer)
- Buerger's disease
- Marfan syndrome
- Giant cell arteritis
Correct answer: Fibromuscular dysplasia (FMD)
Fibromuscular dysplasia (FMD) is a condition causing stenosis or aneurysms in medium-sized arteries, most commonly the renal and internal carotid arteries. The classic angiographic 'string of beads' appearance is caused by alternating areas of medial fibroplasia (causing stenosis) and aneurysmal dilatation. Giant cell arteritis is inflammatory, Buerger's disease is an inflammatory vasculopathy linked to tobacco, and Marfan syndrome is a connective tissue disorder.
Question 114: Which emerging telemedicine application is creating new remote RVT career opportunities?
- Remote radiology film reading only
- Remote interpretation and quality review of vascular studies via telehealth platforms (Correct answer)
- Online prescription renewal services
- Virtual primary care visits
Correct answer: Remote interpretation and quality review of vascular studies via telehealth platforms
Remote quality review and interpretation support via telehealth platforms allow RVTs to review studies, flag findings, and assist interpretation from off-site locations.
Question 115: Which organization specifically accredits vascular ultrasound testing laboratories in the United States for quality standards compliance?
- ARDMS (the RVT credentialing body)
- The Joint Commission (TJC)
- The American College of Radiology (ACR) exclusively
- The Intersocietal Accreditation Commission (IAC) (Correct answer)
Correct answer: The Intersocietal Accreditation Commission (IAC)
The IAC (Intersocietal Accreditation Commission) operates an accreditation program specifically for vascular testing laboratories, evaluating protocols, equipment, personnel credentials, report quality, and QA processes. Many payers and hospitals require IAC accreditation as a condition of reimbursement. ARDMS credentials individuals, not laboratories.
Question 116: A duplex exam shows a dilated, tortuous vessel in the popliteal fossa with arterial waveform and adjacent venous signal. What is the most likely diagnosis?
- Pseudoaneurysm of the popliteal artery
- Popliteal arteriovenous fistula (Correct answer)
- Popliteal vein aneurysm
- Baker's cyst with hemorrhage
Correct answer: Popliteal arteriovenous fistula
An arteriovenous fistula presents with arterialized flow in a dilated venous structure adjacent to the feeding artery.
Question 117: In Ehlers-Danlos syndrome type IV (vascular type), which vessel is at greatest risk for spontaneous rupture?
- Carotid siphon
- Superficial femoral artery
- Abdominal aorta
- Medium-sized arteries such as the celiac, mesenteric, and renal arteries (Correct answer)
Correct answer: Medium-sized arteries such as the celiac, mesenteric, and renal arteries
EDS type IV causes deficient type III collagen, predisposing medium-caliber visceral and renal arteries (and gut) to spontaneous rupture.
Question 118: On abdominal duplex exam, a tardus-parvus waveform in the intrarenal arteries is characterized by:
- Bidirectional turbulent flow at end-diastole
- Prolonged systolic acceleration time and reduced peak systolic velocity (Correct answer)
- High-frequency spectral broadening throughout the cardiac cycle
- Elevated PSV with absent diastolic flow
Correct answer: Prolonged systolic acceleration time and reduced peak systolic velocity
Tardus-parvus describes a dampened, delayed waveform with prolonged acceleration time (>70–100 ms) and low amplitude caused by a proximal obstruction.
Question 119: Which segment of the vertebral artery (V1-V4) is most accessible to duplex ultrasound and is the most common site for atherosclerosis?
- V3 - from C2 to dura (atlantoaxial loop)
- V2 - within the transverse foramina C6 to C2
- V1 - origin from subclavian to C6 transverse foramen (Correct answer)
- V4 - intradural segment to basilar junction
Correct answer: V1 - origin from subclavian to C6 transverse foramen
The V1 segment at the vertebral artery origin from the subclavian is the most common site of atherosclerosis and is accessible to duplex imaging.
Question 120: During peripheral arterial physiologic testing, what is the significance of a 'pole test' (elevation test)?
- It assesses venous valve competence in the lower extremity
- It identifies deep vein thrombosis by elevation-induced pain
- It measures the increase in cardiac output with limb elevation
- It determines the critical closing pressure of limb arteries by elevating the limb until Doppler signal disappears (Correct answer)
Correct answer: It determines the critical closing pressure of limb arteries by elevating the limb until Doppler signal disappears
The pole test elevates the limb to determine the height at which Doppler signal disappears, estimating the effective perfusion pressure in critically ischemic limbs when cuff pressures are unreliable.
Question 121: Which of the following is the first major branch of the internal carotid artery (ICA) after it enters the cranial cavity?
- Posterior communicating artery
- Anterior cerebral artery
- Ophthalmic artery (Correct answer)
- Middle cerebral artery
Correct answer: Ophthalmic artery
The ophthalmic artery is typically the first major branch arising from the supraclinoid segment of the internal carotid artery after it passes through the cavernous sinus and enters the cranial cavity. It supplies blood to the structures of the orbit.
Question 122: A vascular lab's QA program identifies that its sensitivity for detecting >70% internal carotid artery stenosis has dropped from 92% to 78% over one year. The FIRST step in investigation should be:
- Immediately purchase new ultrasound equipment
- Review whether published velocity criteria or scanning protocols were modified during that period (Correct answer)
- Hire an external consultant to audit the lab
- Retrain all technologists on Doppler angle correction
Correct answer: Review whether published velocity criteria or scanning protocols were modified during that period
Changes in diagnostic performance often trace back to modifications in criteria, protocols, or equipment settings; reviewing what changed is the logical first investigative step.
Question 123: What is the expected spectral Doppler waveform morphology in a normally functioning, mature lower extremity reversed saphenous vein bypass graft that is supplying the ankle and foot?
- A 'tardus parvus' waveform
- Low-resistance, monophasic with high diastolic flow
- A continuous, non-pulsatile venous-like signal
- High-resistance, multiphasic (triphasic or biphasic) (Correct answer)
Correct answer: High-resistance, multiphasic (triphasic or biphasic)
A bypass graft assumes the hemodynamic characteristics of the vascular bed it supplies. Since the arteries of a resting lower extremity are a high-resistance bed, a normal graft waveform should be high-resistance, meaning it will be multiphasic (triphasic or strongly biphasic) with sharp systolic upstroke and minimal diastolic flow. [23]
Question 124: What is the average salary range for an RVT in the United States?
- $50,000 - $60,000
- $60,000 - $80,000 (Correct answer)
- $40,000 - $50,000
- $80,000 - $100,000
Correct answer: $60,000 - $80,000
The average salary range for an RVT in the United States typically falls between $60,000 and $80,000 annually. This range can fluctuate based on factors such as geographic location, years of experience, and the type of healthcare facility. RVTs are highly skilled professionals, and their specialized expertise is reflected in competitive compensation.
Question 125: Which duplex ultrasound finding in an arteriovenous fistula (AVF) differentiates it from a pseudoaneurysm?
- Absence of color flow within the lesion
- Arterialized (pulsatile, low-resistance) flow in the adjacent vein (Correct answer)
- To-and-fro waveform at the communication neck
- High-resistance waveform in the feeding artery
Correct answer: Arterialized (pulsatile, low-resistance) flow in the adjacent vein
The hallmark of an AVF is arterialized (pulsatile, high-velocity, low-resistance) flow detected in the draining vein due to direct arteriovenous communication.
Question 126: Which of the following best describes the concept of 'critical stenosis' in arterial hemodynamics?
- Any stenosis detectable by duplex ultrasound
- A 30% diameter reduction causing turbulence
- The degree of stenosis that begins to reduce resting blood flow (Correct answer)
- Total vessel occlusion with no collateral pathways
Correct answer: The degree of stenosis that begins to reduce resting blood flow
Critical stenosis is the threshold (typically ~50–75% diameter reduction) at which the pressure gradient across the lesion begins to reduce resting volumetric flow.
Question 127: An RVT who publishes a peer-reviewed article on carotid artery duplex ultrasound may apply for CME credit under which category?
- Institutional committee service
- Patient outcomes reporting
- Research and publication credit (Correct answer)
- Quality assurance credit
Correct answer: Research and publication credit
ARDMS recognizes peer-reviewed publication as an eligible CME activity, classified under research and publication credit.
Question 128: Which patient preparation instruction is MOST important before performing a mesenteric arterial duplex examination?
- Consume a high-fat meal 30 minutes before the scan
- NPO (nothing by mouth) for at least 6–8 hours prior to the exam (Correct answer)
- No special preparation is required
- Drink 32 oz of water to achieve a full bladder
Correct answer: NPO (nothing by mouth) for at least 6–8 hours prior to the exam
Bowel gas from food or liquid intake significantly degrades visualization of the celiac axis and superior mesenteric artery. Fasting for 6–8 hours minimizes intraluminal gas and promotes mesenteric vasodilation, improving both image quality and the physiologic significance of post-prandial velocity changes.
Question 129: Color Doppler aliasing during an abdominal duplex exam most commonly occurs because:
- The gain setting is too low for adequate penetration
- The angle of insonation is greater than 60 degrees
- The Doppler shift frequency exceeds half the pulse repetition frequency (Nyquist limit) (Correct answer)
- The transducer frequency is too high for abdominal depth
Correct answer: The Doppler shift frequency exceeds half the pulse repetition frequency (Nyquist limit)
Aliasing occurs when detected Doppler frequencies exceed the Nyquist limit (PRF/2), causing the system to misrepresent flow direction and velocity.
Question 130: During TCD microemboli monitoring, which characteristic helps differentiate a gaseous embolus from a particulate embolus?
- Gaseous emboli produce high-intensity (typically >25 dB above background), bidirectional signals; particulate emboli are lower intensity and typically unidirectional (Correct answer)
- Particulate emboli generate a chirping audible tone; gaseous emboli are silent on audio
- Gaseous emboli cause unidirectional signals; particulate emboli cause bidirectional signals
- Gaseous and particulate emboli cannot be reliably differentiated with standard TCD
Correct answer: Gaseous emboli produce high-intensity (typically >25 dB above background), bidirectional signals; particulate emboli are lower intensity and typically unidirectional
High-intensity transient signals (HITS) on TCD mark embolic events. Gaseous emboli (e.g., from cardiac bypass) reflect ultrasound very strongly (>25 dB), are bidirectional, and produce a distinctive 'chirp.' Particulate emboli (e.g., cholesterol, platelet aggregates) are typically lower intensity and unidirectional. This distinction has clinical implications for identifying cardiac vs. atherosclerotic embolic sources.
Question 131: Which parameter obtained during peripheral arterial physiologic testing BEST predicts primary amputation healing at the below-knee level?
- Resting ABI at the ankle
- Popliteal artery duplex velocity
- Below-knee or ankle systolic pressure >70 mmHg or toe pressure >30 mmHg (Correct answer)
- Presence of triphasic waveform at the popliteal level
Correct answer: Below-knee or ankle systolic pressure >70 mmHg or toe pressure >30 mmHg
Below-knee amputation healing is most reliably predicted by adequate perfusion pressure, with ankle or BK pressures >70 mmHg and toe pressures >30 mmHg associated with successful primary healing.
Question 132: A peak systolic velocity of 220 cm/s with an end-diastolic velocity of 85 cm/s in the ICA corresponds to which NASCET stenosis category per the Society of Radiologists in Ultrasound (SRU) consensus criteria?
- 70-99% stenosis (Correct answer)
- Near occlusion
- Less than 50% stenosis
- 50-69% stenosis
Correct answer: 70-99% stenosis
Per SRU criteria, ICA PSV ≥125 cm/s with EDV ≥40 cm/s and ICA/CCA ratio >2.0 indicates 70-99% stenosis requiring closer evaluation.
Question 133: A sonographer is evaluating a patient with a history of DVT one year ago. The common femoral vein appears patent but contains echogenic, thickened walls and the enclosed valve leaflets are immobile. These findings are most characteristic of:
- Chronic post-thrombotic changes. (Correct answer)
- An acute, non-occlusive thrombus.
- An arteriovenous fistula.
- Venous aneurysm.
Correct answer: Chronic post-thrombotic changes.
Chronic post-thrombotic changes are the long-term sequelae of a DVT. Sonographically, this appears as thickened, echogenic vein walls, immobile or 'frozen' valve cusps, and possible residual, organized thrombus (synechiae) that may recanalize. The vein is typically compressible, unlike in an acute DVT.
Question 134: On color Doppler imaging, the classic 'yin-yang' sign is associated with which vascular abnormality?
- Dissecting aneurysm
- Arteriovenous malformation
- Pseudoaneurysm (Correct answer)
- Venous varicosity
Correct answer: Pseudoaneurysm
The yin-yang sign represents bidirectional swirling flow within a pseudoaneurysm sac, with red and blue halves on color Doppler.
Question 135: A diabetic patient has non-compressible tibial arteries with ABIs >1.3. Which alternative test is MOST reliable for assessing arterial perfusion in this patient?
- CT angiography without contrast
- Toe-brachial index (TBI) (Correct answer)
- Segmental limb pressures
- Venous duplex ultrasound
Correct answer: Toe-brachial index (TBI)
The toe arteries are typically spared from medial calcification in diabetics, making the TBI the preferred non-invasive pressure index when ABIs are non-compressible.
Question 136: During segmental pressure testing, a 30 mmHg pressure gradient is found between the proximal thigh and above-knee segments. Where is the disease most likely located?
- Aortoiliac segment
- Tibial vessels
- Superficial femoral artery (Correct answer)
- Popliteal artery
Correct answer: Superficial femoral artery
A gradient >20 mmHg between proximal thigh and above-knee cuffs localizes disease to the superficial femoral artery in the mid-thigh region.
Question 137: What is the primary duplex role during endovenous thermal ablation (EVTA) of the great saphenous vein?
- Guiding catheter tip placement and detecting endothermal heat-induced thrombosis (EHIT) post-procedure (Correct answer)
- Measuring total venous reflux time along the thigh
- Assessing arterial inflow to the limb
- Confirming deep venous valve competence before ablation
Correct answer: Guiding catheter tip placement and detecting endothermal heat-induced thrombosis (EHIT) post-procedure
Ultrasound guides correct catheter positioning (typically 2 cm distal to the saphenofemoral junction) and monitors tumescent anesthesia placement. Post-ablation, the technologist scans for EHIT — thrombus propagation into the deep system — which can occur in the first few days and requires classification and follow-up.
Question 138: Which criterion is most commonly used to recommend surgical or endovascular repair of an infrarenal AAA in a male patient?
- Diameter ≥ 6.0 cm in any patient
- Diameter ≥ 3.0 cm with thrombus present
- Diameter ≥ 4.0 cm or growth > 3 mm/year
- Diameter ≥ 5.5 cm or growth > 10 mm/year (Correct answer)
Correct answer: Diameter ≥ 5.5 cm or growth > 10 mm/year
Standard US guidelines recommend repair for AAAs ≥ 5.5 cm diameter in men or rapid growth > 10 mm per year due to rupture risk.
Question 139: According to the Bernoulli principle as it applies to hemodynamics, what is the relationship between pressure and velocity at the point of maximum arterial stenosis?
- Velocity is highest and pressure is highest.
- Velocity is lowest and pressure is highest.
- Velocity is highest and pressure is lowest. (Correct answer)
- Velocity is lowest and pressure is lowest.
Correct answer: Velocity is highest and pressure is lowest.
The Bernoulli principle describes the conservation of energy, stating that an increase in velocity (kinetic energy) must be accompanied by a decrease in pressure (potential energy). In an arterial stenosis, blood accelerates to pass through the narrowed segment, resulting in the highest velocity and, consequently, the lowest pressure at that specific point.
Question 140: When documenting an accreditation-required quality improvement (QI) project, which element is mandatory for ICAVL compliance?
- Annual equipment replacement schedule
- Monthly staff performance reviews
- Physician re-read rate of greater than 25%
- Evidence of action taken based on findings and outcome reassessment (Correct answer)
Correct answer: Evidence of action taken based on findings and outcome reassessment
ICAVL requires that QI projects demonstrate a complete cycle: identifying the problem, implementing a change, and reassessing outcomes to confirm improvement.
Question 141: Which of the following is the MOST important parameter to document when performing post-angioplasty surveillance of the superficial femoral artery?
- Resistive index of the SFA
- Only ABI before and after exercise
- Cross-sectional area of the artery on B-mode
- PSV at the treatment site, PSV ratio, and waveform character (Correct answer)
Correct answer: PSV at the treatment site, PSV ratio, and waveform character
Post-SFA angioplasty surveillance should document PSV at the treated segment, PSV ratio versus proximal normal SFA, and waveform character to classify residual or recurrent stenosis.
Question 142: According to Bernoulli's principle, as blood accelerates through a stenosis, what happens to lateral pressure within the narrowed segment?
- Lateral pressure decreases (Correct answer)
- Lateral pressure remains unchanged
- Lateral pressure becomes pulsatile
- Lateral pressure increases
Correct answer: Lateral pressure decreases
Bernoulli's principle states that increased kinetic energy (velocity) is accompanied by decreased potential energy (pressure) in the stenosis.
Question 143: During an abdominal aortic duplex exam, the normal infrarenal aorta diameter in an adult male should be less than:
- 3.0 cm (Correct answer)
- 1.5 cm
- 2.0 cm
- 4.0 cm
Correct answer: 3.0 cm
The normal infrarenal aorta diameter is less than 3.0 cm; a diameter of 3.0 cm or greater defines an abdominal aortic aneurysm.
Question 144: The window beneath the systolic peak in a normal arterial spectral waveform is called the spectral window and reflects:
- Laminar plug flow with a narrow velocity profile (Correct answer)
- Turbulent flow
- Aliasing artifact
- Retrograde flow component
Correct answer: Laminar plug flow with a narrow velocity profile
A clear spectral window indicates organized laminar flow where most red blood cells travel at similar velocities near the vessel center.
Question 145: A patient with a history of chronic liver disease undergoes an abdominal duplex exam. Which of the following findings is the most specific indicator of severe portal hypertension?
- Hepatofugal (reversed) flow in the main portal vein. (Correct answer)
- A continuous, non-phasic waveform in the hepatic veins.
- A main portal vein diameter of 14 mm.
- Splenomegaly with a spleen length of 15 cm.
Correct answer: Hepatofugal (reversed) flow in the main portal vein.
While an enlarged portal vein diameter (>13 mm) and splenomegaly are common findings in portal hypertension, the most specific and definitive sign of severe disease is hepatofugal flow in the main portal vein. This indicates that the resistance within the liver is so high that blood flow has reversed its normal direction and is flowing away from the liver through collateral pathways.
Question 146: The posterior inferior cerebellar artery (PICA) most commonly originates from the:
- Posterior cerebral artery
- Basilar artery
- Superior cerebellar artery
- Vertebral artery (Correct answer)
Correct answer: Vertebral artery
PICA typically arises from the distal intracranial vertebral artery, and its occlusion causes the lateral medullary (Wallenberg) syndrome.
Question 147: When insonating at a Doppler angle of 60°, a measured velocity of 100 cm/s is obtained. If the true angle is actually 70°, the calculated velocity will be:
- Lower than the true velocity
- Equal to the true velocity
- Unable to be determined
- Higher than the true velocity (Correct answer)
Correct answer: Higher than the true velocity
cos60° (0.50) > cos70° (0.34); using the smaller cosine (60°) to correct gives a higher velocity estimate than if the true 70° angle were used.
Question 148: A patient with subclavian steal syndrome will demonstrate which finding on vertebral artery duplex?
- Monophasic low-resistance antegrade flow
- Complete reversal of flow direction throughout the cardiac cycle (Correct answer)
- Antegrade high-velocity flow throughout systole and diastole
- Absence of Doppler signal bilaterally
Correct answer: Complete reversal of flow direction throughout the cardiac cycle
Complete subclavian steal causes full reversal of vertebral artery flow as blood is 'stolen' retrograde to supply the ischemic subclavian artery territory.
Question 149: Which of the following is considered a REQUIRED component of a complete vascular duplex examination report?
- Insurance authorization code and billing CPT number
- Comparison to the patient's prior imaging from outside institutions
- The technologist's personal clinical impression and treatment recommendation
- Clinical indication, technical description of findings, and diagnostic impression (Correct answer)
Correct answer: Clinical indication, technical description of findings, and diagnostic impression
A complete vascular report must include the reason the study was ordered (indication), a description of the vascular findings with supporting measurements, and a diagnostic conclusion or impression. These elements ensure the referring clinician has the information needed for clinical management.
Question 150: Which RVT examination topic requires understanding of plaque morphology classification including echolucent vs. echogenic characteristics?
- Transcranial Doppler monitoring
- Carotid artery duplex evaluation (Correct answer)
- Venous reflux testing
- Lower extremity venous mapping
Correct answer: Carotid artery duplex evaluation
Carotid artery duplex evaluation includes plaque morphology assessment, where echolucent (soft) plaques carry higher embolic risk than echogenic (calcified) plaques.
Question 151: On a lower extremity venous duplex, a patient shows spontaneous flow in the femoral vein but no augmentation with calf compression. What does this most likely indicate?
- Normal variant
- Severe venous insufficiency with reflux
- Occlusive thrombus between the probe and compression site (Correct answer)
- Arteriovenous fistula
Correct answer: Occlusive thrombus between the probe and compression site
Absence of augmentation despite visible flow indicates an obstructive lesion between the compression site and the transducer.
Question 152: When evaluating a patient for upper extremity arterial disease, a blood pressure difference greater than how many mmHg between arms is clinically significant?
- 10 mmHg (Correct answer)
- 20 mmHg
- 30 mmHg
- 5 mmHg
Correct answer: 10 mmHg
An inter-arm pressure difference >10 mmHg suggests subclavian or axillary artery stenosis and warrants further evaluation; >15-20 mmHg is considered diagnostic of subclavian steal syndrome.
Question 153: What is the maximum number of times a candidate may attempt the ARDMS RVT examination within a 12-month period?
- Three attempts (Correct answer)
- Unlimited attempts
- Two attempts
- One attempt only
Correct answer: Three attempts
ARDMS limits candidates to three examination attempts per 12-month period, with required waiting periods between attempts.
Question 154: A tardus-parvus waveform pattern distal to an arterial obstruction is characterized by:
- Rapid systolic upstroke and high peak velocity
- Delayed, rounded systolic peak with reduced amplitude and loss of diastolic reversal (Correct answer)
- Absent diastolic flow with normal systolic velocity
- Triphasic waveform with increased peak systolic velocity
Correct answer: Delayed, rounded systolic peak with reduced amplitude and loss of diastolic reversal
Tardus-parvus (slow-small) describes the damped, delayed waveform seen downstream from a hemodynamically significant stenosis or occlusion.
Question 155: The Doppler equation used to calculate flow velocity is: v = (f_d × c) / (2 × f_0 × cos θ). What does 'θ' represent?
- The angle of incidence at the tissue boundary
- The angle between the ultrasound beam and the direction of blood flow (Correct answer)
- The angle between the transducer face and the vessel wall
- The beam divergence angle beyond the focal zone
Correct answer: The angle between the ultrasound beam and the direction of blood flow
θ is the Doppler angle—the angle between the insonating beam and the axis of blood flow; as θ approaches 90°, cos θ approaches 0 and velocity calculation becomes unreliable.
Question 156: In portal vein duplex evaluation, normal portal vein flow is described as hepatopetal with a velocity of approximately:
- 5–10 cm/s with marked phasicity
- 60–90 cm/s with continuous non-phasic flow
- Greater than 100 cm/s with turbulent waveform
- 16–40 cm/s with mild respiratory phasicity (Correct answer)
Correct answer: 16–40 cm/s with mild respiratory phasicity
Normal portal vein flow is directed toward the liver (hepatopetal) at 16–40 cm/s, with slight variation related to respiration and cardiac pulsatility.
Question 157: An increased pulsatility index (PI) proximal to a segment of arterial occlusion suggests:
- Increased downstream resistance due to the obstruction (Correct answer)
- Hyperdynamic cardiac function
- Improved collateral circulation
- Arteriovenous fistula formation
Correct answer: Increased downstream resistance due to the obstruction
Proximal to an occlusion, high outflow resistance causes the waveform to become more pulsatile with reduced or absent diastolic flow.
Question 158: Power Doppler differs from conventional color flow Doppler primarily in that it displays:
- Bidirectional flow with higher velocity sensitivity
- Pulsatility index mapped in color across the image
- The amplitude (power) of the Doppler signal rather than frequency shift (Correct answer)
- Mean velocity values averaged across the vessel diameter
Correct answer: The amplitude (power) of the Doppler signal rather than frequency shift
Power Doppler maps the intensity (energy) of the returning Doppler signal, making it more sensitive to slow flow and small vessels but providing no directional information.
Question 159: What is the primary purpose of the Circle of Willis in the cerebrovascular system?
- To supply blood to the cerebellum
- To provide a collateral pathway for cerebral perfusion (Correct answer)
- To regulate intracranial pressure
- To act as the main venous drainage system
Correct answer: To provide a collateral pathway for cerebral perfusion
The Circle of Willis is an arterial anastomosis at the base of the brain that connects the anterior (internal carotid arteries) and posterior (vertebrobasilar system) circulations. Its primary function is to provide redundancy and collateral blood flow, which can help maintain cerebral perfusion if a major contributing artery becomes stenosed or occluded.
Question 160: During ultrasound-guided central venous access, the primary advantage of real-time needle visualization over landmark technique is:
- Direct visualization of needle tip position within the target vessel lumen in real time (Correct answer)
- Elimination of the need for post-procedure chest X-ray
- Automatic calculation of catheter depth required
- Confirmation of venous (vs. arterial) waveform before catheter insertion
Correct answer: Direct visualization of needle tip position within the target vessel lumen in real time
Real-time ultrasound guidance allows the operator to see the needle tip entering the vessel lumen, confirming correct placement before guidewire advancement. This directly reduces complications such as inadvertent arterial puncture, pneumothorax, and posterior wall perforation compared to landmark-only technique.
Question 161: Which document should a vascular laboratory maintain to demonstrate that technologists have reviewed and understood updated scanning protocols?
- Accreditation renewal application
- Equipment maintenance contracts
- Competency sign-off sheets or training attestation records (Correct answer)
- Daily patient log with scan times
Correct answer: Competency sign-off sheets or training attestation records
Signed competency attestation records provide documented evidence that staff have been trained on and understand current protocols, a key ICAVL and Joint Commission requirement.
Question 162: What is a potential non-clinical career path for an RVT?
- Physical therapy assistant
- Nursing management
- Ultrasound equipment sales (Correct answer)
- Pharmaceutical research
Correct answer: Ultrasound equipment sales
A potential non-clinical career path for an RVT is in ultrasound equipment sales. Their deep understanding of ultrasound technology, clinical applications, and the needs of sonographers makes them ideal candidates to represent and sell imaging equipment. This role leverages their technical expertise in a business-oriented setting.
Question 163: Fibromuscular dysplasia (FMD) of the internal carotid artery most commonly affects which segment?
- Petrous ICA
- Cavernous ICA siphon
- Mid-cervical ICA (C1-C2 level) (Correct answer)
- Proximal ICA just above the bifurcation
Correct answer: Mid-cervical ICA (C1-C2 level)
FMD most commonly affects the mid-cervical segment of the ICA at the C1-C2 vertebral level, producing the classic 'string of beads' appearance.
Question 164: A sonographer holds the RDMS credential and wants to add the RVT. Which exam pathway might allow them to waive prerequisites?
- Holding a qualifying ARDMS credential may satisfy certain prerequisites for the RVT application (Correct answer)
- They must start the process from scratch with no exemptions
- They must obtain a physician's license before applying
- They need five additional years of cardiac experience
Correct answer: Holding a qualifying ARDMS credential may satisfy certain prerequisites for the RVT application
Holding certain ARDMS credentials, such as the RDMS, may satisfy prerequisite requirements for applying to additional ARDMS specialty examinations.
Question 165: According to IAC Standards for Vascular Testing, which of the following is a required component of the final, signed interpretation report?
- A comparison with previous relevant studies, if available. (Correct answer)
- The name of the sonographer who performed the study.
- The total time taken to complete the examination.
- The specific make and model of the ultrasound machine.
Correct answer: A comparison with previous relevant studies, if available.
The IAC standards require that the final interpretation report be comprehensive to provide maximum clinical value. A key required element is the comparison of current findings to previous studies when they are available. This allows for assessment of disease progression, stability, or post-intervention status. While the sonographer's name is often included on a worksheet, it is the comparison to priors that is a mandatory reporting component for clinical context.
Question 166: A surveillance duplex of an above-knee femoropopliteal PTFE graft shows a mid-graft PSV of 18 cm/s. What is the most appropriate action?
- No action; low velocity is expected in PTFE grafts
- Urgent clinical referral for angiography, as low graft velocity predicts impending thrombosis (Correct answer)
- Prescribe aspirin and recheck in 3 months
- Repeat in 6 months as per standard protocol
Correct answer: Urgent clinical referral for angiography, as low graft velocity predicts impending thrombosis
A mid-graft PSV <25 cm/s is a strong predictor of impending graft thrombosis and warrants urgent clinical evaluation and possible intervention.
Question 167: Which duplex ultrasound finding is MOST suggestive of a hemodynamically significant stenosis in an AV fistula requiring intervention?
- Pulsatile waveform pattern in the outflow vein
- PSV ratio >2:1 across a focal stenosis with access flow <400 mL/min (Correct answer)
- Mild color-flow aliasing throughout the entire fistula body
- PSV of 180 cm/s at the venous anastomosis with a normal Qa
Correct answer: PSV ratio >2:1 across a focal stenosis with access flow <400 mL/min
A PSV ratio >2:1 (stenotic segment vs. adjacent normal segment) combined with a reduced access flow (<400 mL/min) meets the threshold for intervention in most clinical guidelines. Isolated velocity elevation without flow reduction may not be hemodynamically significant; both criteria together confirm clinically meaningful stenosis.
Question 168: A patient undergoes carotid endarterectomy (CEA). Intraoperative TCD monitoring detects a sudden drop in MCA mean velocity to below 15 cm/s after cross-clamping. This indicates:
- Hyperemic response to ischemia
- Cerebral hypoperfusion requiring shunt placement (Correct answer)
- Successful shunting with normal perfusion restored
- Vasospasm from surgical manipulation
Correct answer: Cerebral hypoperfusion requiring shunt placement
An MCA mean velocity <15 cm/s or >50% drop from baseline after carotid cross-clamp indicates inadequate collateral flow and warrants intraoperative shunting.
Question 169: A patient is referred for a cerebrovascular ultrasound due to symptoms of vertebrobasilar insufficiency (VBI). Which of the following symptoms is LEAST likely to be associated with this condition?
- Drop attacks (sudden leg weakness)
- Bilateral vision loss (diplopia)
- Vertigo and dizziness
- Unilateral facial droop (Correct answer)
Correct answer: Unilateral facial droop
Vertebrobasilar insufficiency results from reduced blood flow to the posterior circulation of the brain. Symptoms typically involve structures supplied by the vertebral and basilar arteries, such as the cerebellum and brainstem, leading to vertigo, vision changes, and coordination issues. A unilateral facial droop is a classic symptom of anterior circulation stroke, often involving the middle cerebral artery territory, not typically isolated in VBI.
Question 170: Which abdominal duplex finding in a patient with known atherosclerosis suggests the presence of chronic mesenteric ischemia rather than acute mesenteric ischemia?
- Collateral vessel formation with retrograde filling of the SMA via the arc of Riolan or marginal artery (Correct answer)
- Absent Doppler signal in the SMA with no detectable collaterals
- High-resistance monophasic SMA waveform in a fasting state only
- Normal fasting SMA waveform with increased postprandial velocity
Correct answer: Collateral vessel formation with retrograde filling of the SMA via the arc of Riolan or marginal artery
Chronic ischemia allows time for collateral development such as the arc of Riolan; acute occlusion does not allow collateral formation and presents with absent flow and no collaterals.
Question 171: Which of the following is a primary purpose for performing an exercise stress test in a patient with suspected peripheral arterial disease (PAD) and a borderline resting ABI?
- To evaluate for coronary artery disease.
- To determine the patient's pain tolerance.
- To unmask a hemodynamically significant stenosis that is not apparent at rest. (Correct answer)
- To measure the maximum heart rate achieved during exercise.
Correct answer: To unmask a hemodynamically significant stenosis that is not apparent at rest.
Exercise increases blood flow demand in the lower extremities. In a patient with PAD, a stenosis that is not flow-limiting at rest may become significant during exercise, causing a drop in ankle pressures. This helps to confirm the diagnosis and assess the functional severity of the disease when resting studies are inconclusive.
ARDMS Vascular Technology (VT) Exam
The ARDMS Vascular Technology (VT) exam awards the Registered Vascular Technologist (RVT) credential, assessing competency in vascular sonography including cerebrovascular, peripheral arterial, peripheral venous, and abdominal vascular testing.
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Sources & references
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