RVT Abdominal Vascular Duplex Exams 3 — Questions and Answers
Question 1: On abdominal duplex exam, a tardus-parvus waveform in the intrarenal arteries is characterized by:
- Prolonged systolic acceleration time and reduced peak systolic velocity (Correct answer)
- Elevated PSV with absent diastolic flow
- Bidirectional turbulent flow at end-diastole
- High-frequency spectral broadening throughout the cardiac cycle
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 2: During mesenteric duplex imaging, the inferior mesenteric artery (IMA) is best evaluated in which patient position and window?
- Supine, anterior midline transabdominal approach at the level of L3-L4 (Correct answer)
- Left lateral decubitus, left flank approach
- Prone, posterior approach at the level of L1
- Supine, subcostal approach angled toward the spine
Correct answer: Supine, anterior midline transabdominal approach at the level of L3-L4
The IMA originates from the anterior aortic wall at approximately L3-L4 and is best accessed from the anterior midline in a supine patient.
Question 3: Which duplex finding best differentiates a true aortic aneurysm from a pseudoaneurysm of the aorta?
- A true aneurysm involves all three vessel wall layers with fusiform or saccular dilation, while a pseudoaneurysm has no true wall (Correct answer)
- A pseudoaneurysm always contains organized thrombus, while a true aneurysm does not
- A true aneurysm has yin-yang flow pattern on color Doppler
- A pseudoaneurysm is always smaller than 3 cm in diameter
Correct answer: A true aneurysm involves all three vessel wall layers with fusiform or saccular dilation, while a pseudoaneurysm has no true wall
A true aneurysm is defined by full-thickness wall involvement, while a pseudoaneurysm is a contained rupture with a fibrous capsule rather than a true vascular wall.
Question 4: In a patient with an infrarenal AAA being followed by duplex surveillance, which measurement is the standard for monitoring aneurysm growth?
- Maximum outer-wall-to-outer-wall anteroposterior diameter (Correct answer)
- Inner lumen diameter excluding mural thrombus
- Aneurysm length from neck to bifurcation
- Maximum transverse diameter of the lumen only
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 5: 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 6: During splenic artery duplex evaluation, the normal waveform pattern reflects which hemodynamic state?
- Low-resistance flow with continuous forward diastolic flow (Correct answer)
- High-resistance triphasic flow with brief flow reversal
- Monophasic flat waveform with no diastolic component
- 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 7: 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)
- Abdominal aortic aneurysm with laminar thrombus
- Aortic dissection with a false lumen
- Retroperitoneal hematoma compressing the aorta
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.
RVT Abdominal Vascular Duplex Exams 3
On abdominal duplex exam, a tardus-parvus waveform in the intrarenal arteries is characterized by: