VT Abdominal Aorta & Visceral Vessels 2 — Questions and Answers
Question 1: Which Doppler waveform characteristic is most consistent with a hemodynamically significant celiac artery stenosis?
- Monophasic low-resistance waveform distal to the lesion
- Elevated peak systolic velocity with post-stenotic turbulence (Correct answer)
- Absent diastolic flow throughout the vessel
- Bidirectional flow at the stenosis site
Correct answer: Elevated peak systolic velocity with post-stenotic turbulence
A hemodynamically significant stenosis produces elevated peak systolic velocity (PSV >200 cm/s) at the lesion site with post-stenotic spectral broadening and turbulence.
Question 2: A patient presents with postprandial abdominal pain. Duplex demonstrates compression of the celiac axis with expiration but normal flow with inspiration. This pattern is most consistent with:
- Atherosclerotic celiac stenosis
- Median arcuate ligament syndrome (MALS) (Correct answer)
- Superior mesenteric artery aneurysm
- Aortic dissection involving the celiac origin
Correct answer: Median arcuate ligament syndrome (MALS)
MALS is caused by compression of the celiac axis by the median arcuate ligament, which characteristically worsens with expiration when the diaphragm descends.
Question 3: The normal PSV of the superior mesenteric artery (SMA) in the fasting state is approximately:
- 50–100 cm/s
- 125–175 cm/s (Correct answer)
- 200–300 cm/s
- 350–400 cm/s
Correct answer: 125–175 cm/s
Fasting SMA PSV is typically 125–175 cm/s with a high-resistance triphasic waveform; postprandial flow increases significantly.
Question 4: When evaluating for renal artery stenosis (RAS), which indirect Doppler parameter obtained from the segmental or interlobar arteries best reflects a hemodynamically significant proximal stenosis?
- Resistive index (RI) >0.80
- Accelerated systolic upstroke (tardus-parvus waveform) (Correct answer)
- Absent end-diastolic flow
- Reversed diastolic flow
Correct answer: Accelerated systolic upstroke (tardus-parvus waveform)
A tardus-parvus waveform — characterized by a delayed, blunted systolic upstroke (AT >0.07 s, AI <3 m/s²) — is the hallmark indirect sign of significant proximal RAS.
Question 5: Which of the following represents the accepted peak systolic velocity (PSV) threshold for diagnosing ≥60% SMA stenosis?
- PSV >200 cm/s
- PSV >275 cm/s
- PSV >300 cm/s (Correct answer)
- PSV >400 cm/s
Correct answer: PSV >300 cm/s
A PSV >300 cm/s in the SMA is the widely accepted threshold for diagnosing ≥60% (hemodynamically significant) stenosis.
Question 6: An abdominal aortic aneurysm (AAA) is defined by an aortic diameter exceeding:
- 2.5 cm
- 3.0 cm (Correct answer)
- 3.5 cm
- 4.0 cm
Correct answer: 3.0 cm
An AAA is defined as an aortic diameter ≥3.0 cm, representing a 50% increase over the normal infrarenal aortic diameter of ~2.0 cm.
Question 7: Which ultrasound measurement should be used to document AAA size for surveillance purposes?
- Inner-edge to inner-edge AP diameter
- Outer-edge to outer-edge AP diameter (Correct answer)
- Inner-edge to outer-edge AP diameter
- Transverse diameter only
Correct answer: Outer-edge to outer-edge AP diameter
Society guidelines recommend outer-to-outer wall AP diameter measurement in a true transverse plane perpendicular to the aortic lumen for accurate surveillance.
VT Abdominal Aorta & Visceral Vessels 2
Which Doppler waveform characteristic is most consistent with a hemodynamically significant celiac artery stenosis?