In SMA Doppler, a rapid upstroke is a characteristic of which condition?

• A. Normal waveforms in fasting and postprandial
• B. Stenosis
• C. Flow reversal
• D. Occlusion

Answer: (A)

A brisk systolic upstroke reflects normal, nonstenotic inflow in the SMA. When the artery is patent, the waveform rises rapidly to peak velocity and then shows forward diastolic flow, with postprandial states typically bringing more continuous forward flow due to vasodilation but without sacrificing the sharp onset of systole. In contrast, significant proximal stenosis produces a damped, delayed upstroke (tardus parvus) and often a higher peak velocity distal to the narrowing, not a rapid rise. Flow reversal and occlusion imply abnormal hemodynamics beyond a simple rapid upstroke, whereas normal fasting and postprandial waveforms display that brisk, clean upstroke.