RVT Vascular Pathology and Aneurysms 2 — Questions and Answers
Question 1: Which sonographic finding is most characteristic of a mycotic aneurysm compared to an atherosclerotic aneurysm?
- Irregular, saccular morphology with surrounding soft tissue changes (Correct answer)
- Fusiform dilation with calcified wall
- Smooth intimal surface with laminated thrombus
- Bilateral symmetric involvement
Correct answer: Irregular, saccular morphology with surrounding soft tissue changes
Mycotic aneurysms are typically saccular and irregular with surrounding inflammatory/infectious soft tissue changes, unlike the fusiform atherosclerotic type.
Question 2: A patient presents with a pulsatile abdominal mass and a bruit. Duplex ultrasound shows an aortic diameter of 4.2 cm. According to standard guidelines, what is the recommended surveillance interval?
- Every 6 months
- Every 12 months (Correct answer)
- Every 3 months
- Immediate surgical referral
Correct answer: Every 12 months
AAAs between 4.0–4.9 cm are typically surveilled annually per most US guidelines (e.g., SVS).
Question 3: What is the primary mechanism by which turbulent flow contributes to aneurysm wall stress?
- Increased wall shear stress causes smooth muscle cell apoptosis and extracellular matrix degradation (Correct answer)
- Decreased velocity reduces oxygen delivery to the adventitia
- Laminar flow disruption causes thrombus embolization
- Elevated venous pressure transmits back to the arterial wall
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 4: On duplex ultrasound of a peripheral artery aneurysm, which waveform pattern within the aneurysm sac is most commonly observed?
- Monophasic low-resistance flow throughout
- To-and-fro or swirling flow with low-velocity turbulence (Correct answer)
- High-resistance triphasic flow
- Absent flow signal despite patent lumen
Correct answer: To-and-fro or swirling flow with low-velocity turbulence
Aneurysm sacs typically display swirling, turbulent, or to-and-fro flow patterns due to loss of laminar flow architecture.
Question 5: Which of the following best defines a pseudoaneurysm (false aneurysm)?
- Dilation involving all three layers of the arterial wall
- A contained hematoma communicating with the arterial lumen through a wall defect (Correct answer)
- An arteriovenous fistula with aneurysmal dilation
- Concentric calcification of the arterial wall without dilation
Correct answer: A contained hematoma communicating with the arterial lumen through a wall defect
A pseudoaneurysm lacks the true arterial wall layers; it is a pulsatile hematoma communicating with the vessel through a neck.
Question 6: Femoral pseudoaneurysms are most commonly caused by which etiology in contemporary vascular practice?
- Blunt trauma
- Iatrogenic arterial puncture (post-catheterization) (Correct answer)
- Atherosclerotic degeneration
- Connective tissue disorder
Correct answer: Iatrogenic arterial puncture (post-catheterization)
The majority of femoral pseudoaneurysms in modern practice result from arterial access during cardiac or vascular catheterization procedures.
Question 7: When performing ultrasound-guided thrombin injection for a femoral pseudoaneurysm, what is the most critical step before injection?
- Confirm absence of AV fistula and clearly visualize the neck of the pseudoaneurysm (Correct answer)
- Administer systemic anticoagulation to prevent distal thrombosis
- Compress the femoral vein to redirect flow
- Measure the peak systolic velocity in the native artery
Correct answer: Confirm absence of AV fistula and clearly visualize the neck of the pseudoaneurysm
Identifying the neck and confirming no concurrent AV fistula is essential to prevent thrombin from entering the native circulation.
RVT Vascular Pathology and Aneurysms 2
Which sonographic finding is most characteristic of a mycotic aneurysm compared to an atherosclerotic aneurysm?