CTA detects active bleeding at what rate?
CTA = 0.3-0.5 mL/min. DSA detects bleeding at 0.5 mL/min and scintigraphy with 99mTc-labeled red blood cells detects bleeding at 0.1 mL/min, i.e. CTA detects bleeding at a higher rate than DSA.
What are the features of active bleeding on CT.
Hyperdense focus not present on the non-contrast phase, that changes appearance from the arterial to portal venous phases.
Which phase is the most sensitive?
Portal venous phase allows more time for extravasated blood to pool, making it larger than on arterial phase.
On the arterial and portal venous phase images there is a 1 cm region of vivid enhancement in the first part of duodenum, that was not present on the non-contrast images. This region receives supply from the gastroduodenal artery. No intraluminal contrast extravasation is seen elsewhere in the bowel.
Gallstones incidentally noted. The liver, spleen, pancreas and right kidney are unremarkable. The left kidney is mildly atrophic with regions of cortical scarring. A small left and tiny right pleural effusion is noted.
Conclusion:
The site of active haemorrhage is localised to the proximal duodenum.