In a patient with active lower gastrointestinal bleeding undergoing mesenteric angiography, the minimum rate of contrast extravasation generally required for the bleeding site to be visible as active extravasation is approximately:

• A 50 mL/min
• B 5 to 10 mL/min
• C 0.5 to 1 mL/min ✓
• D 0.05 mL/min

Explanation

Conventional digital subtraction angiography detects extravasation only at rates of roughly 0.5 to 1 mL/min or greater, which explains why angiography can be negative in clinically significant bleeds that are intermittent or slower. This limitation motivates provoking maneuvers, delayed phase imaging, or CT angiography first, since multidetector CT detects bleeding at lower rates around 0.3 mL/min.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.