VT Abdominal Aorta & Visceral Vessels 3 — Questions and Answers
Question 1: An endoleak after EVAR in which blood flows into the aneurysm sac from lumbar or inferior mesenteric artery branches is classified as:
- Type I endoleak
- Type II endoleak (Correct answer)
- Type III endoleak
- Type IV endoleak
Correct answer: Type II endoleak
Type II endoleaks arise from retrograde flow into the sac via collateral vessels such as lumbar arteries or the inferior mesenteric artery.
Question 2: In a patient with suspected chronic mesenteric ischemia, which finding would MOST support the diagnosis on duplex ultrasound?
- Normal SMA PSV with low-resistance waveform
- High-resistance waveform in the SMA with RI >0.90
- Celiac PSV >200 cm/s AND SMA PSV >275 cm/s (Correct answer)
- Monophasic celiac waveform with normal SMA flow
Correct answer: Celiac PSV >200 cm/s AND SMA PSV >275 cm/s
Chronic mesenteric ischemia typically requires stenosis of at least two of the three mesenteric vessels; concurrent elevated PSV in both the celiac (>200 cm/s) and SMA (>275 cm/s) supports the diagnosis.
Question 3: Which portion of the abdominal aorta is most commonly involved by atherosclerosis?
- Suprarenal aorta
- Pararenal aorta
- Infrarenal aorta (Correct answer)
- Thoracoabdominal aorta
Correct answer: Infrarenal aorta
The infrarenal aorta experiences the greatest degree of atherosclerotic disease due to altered flow patterns, reduced elastic tissue, and hemodynamic stress at the aortic bifurcation.
Question 4: During duplex evaluation of the inferior mesenteric artery (IMA), which finding is considered normal?
- High-resistance triphasic waveform in the fasting state (Correct answer)
- Continuous forward diastolic flow at rest
- PSV consistently >300 cm/s
- Reversed systolic flow toward the aorta
Correct answer: High-resistance triphasic waveform in the fasting state
Like the SMA in fasting state, the IMA normally demonstrates a high-resistance triphasic waveform reflecting low metabolic demand of the non-stimulated bowel.
Question 5: A Type I endoleak detected on surveillance ultrasound after EVAR is significant because:
- It spontaneously resolves in >90% of cases
- It represents perigraft flow at the attachment zones and carries risk of sac pressurization and rupture (Correct answer)
- It causes sac shrinkage
- It is treated conservatively without intervention
Correct answer: It represents perigraft flow at the attachment zones and carries risk of sac pressurization and rupture
Type I endoleaks arise at the proximal or distal graft attachment zones and directly pressurize the aneurysm sac, requiring prompt reintervention to prevent rupture.
Question 6: The celiac axis typically arises from the aorta at which vertebral level?
- T10–T11
- T12–L1 (Correct answer)
- L1–L2
- L2–L3
Correct answer: T12–L1
The celiac axis originates from the anterior aorta at the T12–L1 vertebral level, just below the aortic hiatus of the diaphragm.
Question 7: During a renal artery duplex, what is the purpose of calculating the renal-aortic ratio (RAR)?
- To estimate glomerular filtration rate
- To identify accessory renal arteries
- To correct for variation in cardiac output when assessing renal artery stenosis (Correct answer)
- To differentiate hydronephrosis from renal vein thrombosis
Correct answer: To correct for variation in cardiac output when assessing renal artery stenosis
The RAR (renal artery PSV ÷ aortic PSV) corrects for high or low cardiac output states; an RAR >3.5 suggests ≥60% renal artery stenosis.
VT Abdominal Aorta & Visceral Vessels 3
An endoleak after EVAR in which blood flows into the aneurysm sac from lumbar or inferior mesenteric artery branches is classified as: