Visceral Vascular

Superior Mesenteric Artery (SMA) and Inferior Mesenteric Artery (IMA)

1. Normal flow

a. No focal velocity increase

b. No distal turbulence

c. Per the literature, SMA and IMA stenosis < 50% is difficult to detect accurately

2. Stenosis ≥ 70%

a. Peak systolic velocity (PSV) ≥ 275 cm/sec

b. End diastolic velocity (EDV) ≥ 70 cm/sec

3. Occlusion

a. No flow noted through the SMA

b. Collateral flow detected (i.e., increased inferior mesenteric artery flow)

c. Occasionally, due to gas and its smaller size, the IMA may not be visualized

Celiac Axis

1. Normal flow

a. No focal velocity increase

b. No spectral broadening distal turbulence

2. Stenosis ≥ 70%

a. PSV ≥ 200 cm/sec

b. EDV ≥ 100 cm/sec

c. Downstream bruit, post-stenotic turbulence and velocity decreases

d. Spectral broadening

3. Occlusion of Celiac Axis

a. No flow detected in the celiac artery

b. Retrograde flow in the common hepatic artery

c. Flow in the splenic artery is dampened

4. Median Arcuate Ligament Compression

a. Elevation in PSV ≥ 200 cm/sec with expiration, or in supine position

b. Doppler bruit with distal turbulence

c. Normal velocities (< 200 cm/sec PSV) with inspiration, or when examined in sitting position