Superior Mesenteric Artery (SMA) Doppler Ultrasound Normal Vs Abnormal Images | Vascular USG Cases

Normal SMA (Fasting):
Sharp systolic Peak
High resistance flow
Variable flow during diastole (slow forward flow/flow reversal)
PSV: 110 to 180 cm/s approx.
EDV: Less than 55 cm/s approx. (variable)
RI: 0.5 to 0.7

Normal SMA (PostPrandial)
Increased PSV and EDV
Flow reversal absent
Low resistance flow

≥70% SMA Stenosis:
Narrowing of SMA lumen
PSV ≥ 275cm/s
Causes mesenteric ischaemia

SMA Dissection:
Intimal Flap: An intimal flap is a membranelike structure that oscillates with the heartbeat within the vessel lumen, dividing it into true and false lumens. This is a direct sign of dissection.
Presence of a False Lumen: The hallmark of artery dissection is the presence of a false lumen created by the intimal tear. This may appear as an additional, parallel channel within the SMA on ultrasound.