CASE

A 57 year old patient with history of diverticulosis presents with hematochezia and lightheadedness. He has a remote history of two prior episodes of lower GI bleeding requiring embolization. Hemoglobin on presentation is 8.5, down from 9.7 two days earlier when he was admitted with the same problem but had a negative CTA and ultimately discharged. Repeat CTA again shows no active bleeding. He is admitted and hemoglobin the next morning is 7.8 with another episode of hematochezia overnight.

Which of the following is most sensitive for gastrointestinal bleeding?

A. CT angiography

B. Tagged RBC scan

C. Invasive catheter-based angiography

D. Pill endoscopy