What are the normal duplex velocities of the mesenteric arteries?

Normal Duplex Velocities of the Mesenteric Arteries

The normal peak systolic velocity (PSV) for the superior mesenteric artery (SMA) is less than 295 cm/s, for the celiac artery (CA) less than 240 cm/s, and for the inferior mesenteric artery (IMA) less than 250 cm/s. These values represent the threshold velocities below which significant stenosis is unlikely.

Normal Velocity Parameters for Mesenteric Arteries

Superior Mesenteric Artery (SMA)

• Normal PSV: <295 cm/s
• Stenosis thresholds:
  • ≥295 cm/s indicates ≥50% stenosis (sensitivity 87%, specificity 89%) 1
  • ≥400 cm/s indicates ≥70% stenosis (sensitivity 72%, specificity 93%) 1
• Normal end-diastolic velocity (EDV): <45 cm/s 1

Celiac Artery (CA)

• Normal PSV: <240 cm/s
• Stenosis thresholds:
  • ≥240 cm/s indicates ≥50% stenosis (sensitivity 87%, specificity 83%) 1
  • ≥320 cm/s indicates ≥70% stenosis (sensitivity 80%, specificity 89%) 1
• Normal EDV: <40 cm/s 1

Inferior Mesenteric Artery (IMA)

• Normal PSV: <250 cm/s
• Stenosis threshold: ≥250 cm/s indicates ≥50% stenosis (sensitivity 90%, specificity 96%) 2
• Normal EDV: <80-90 cm/s 2

Technical Considerations for Mesenteric Duplex Ultrasound

Duplex ultrasound of mesenteric vessels requires specific technical considerations for accurate assessment:

• Patient preparation: Examination should be performed in a fasting state and early in the day to avoid bowel gas interference 3
• Positioning: Supine position with slight head elevation to relax abdominal muscles
• Breathing technique: Suspended respiration during critical measurements
• Vessel visualization: The atherosclerotic lesions typically occur at the origins of vessels from the aorta 3

Clinical Applications and Limitations

Duplex ultrasound serves as an excellent initial screening tool for mesenteric artery disease with important clinical implications:

• Diagnostic accuracy: Overall accuracy of approximately 90% for detection of significant stenosis when performed in experienced laboratories 3
• Screening value: Useful initial test for supporting clinical diagnosis of chronic mesenteric ischemia 3

Limitations

• Technical challenges: Visualization can be difficult due to overlying bowel gas, obesity, and vascular calcifications 3
• Limited utility: Less effective for detecting distal arterial emboli or diagnosing nonocclusive mesenteric ischemia 3
• Patient discomfort: Pressure applied during examination may cause pain, limiting evaluation in acute settings 3

Important Caveats

1. Stented vessels require different criteria: Duplex velocity criteria developed for native arteries overestimate stenosis in stented mesenteric arteries 4, 5
2. Laboratory validation: Each vascular laboratory should validate these criteria against their own angiographic correlations 1
3. Post-prandial testing: Diagnostic performance may be improved by post-prandial testing in some cases 3

Diagnostic Algorithm for Suspected Mesenteric Ischemia

1. Initial evaluation: Duplex ultrasound with B-mode and Doppler waveform analysis
2. If inconclusive: Proceed to CTA or gadolinium-enhanced MRA 3
3. If further clarification needed: Consider diagnostic angiography, particularly lateral aortography 3

Accurate interpretation of mesenteric artery velocities is crucial for early detection of mesenteric ischemia, which can significantly reduce morbidity and mortality associated with this potentially life-threatening condition.