Routine abdominal radiographs are often obtained in patients with GI bleeding. In the absence of specific indications, they are of limited value. Similarly, routine admission chest x-rays for patients with acute GI hemorrhage, even those admitted to the intensive care unit, have been shown to be of limited utility in the absence of known pulmonary disease or abnormal findings on lung exam.5 Barium contrast studies are similarly of limited diagnostic value in an emergency setting. Furthermore, barium limits the use of subsequent endoscopy or angiography.
Angiography can sometimes detect the site of bleeding, particularly in cases of obscure lower tract hemorrhage. Moreover, angiography permits therapeutic options such as transcatheter arterial embolization or the infusion of vasoconstrictive agents. However, to be diagnostic, angiography requires a relatively brisk bleeding rate (0.5 to 2.0 mL/min).
Technetium-labeled red cell scans have also been used to localize the site of bleeding in obscure hemorrhage. Such localization can be used to map the therapeutic approach, whether via angiography or operatively. Scintigraphy appears more sensitive than angiography and can localize the site of bleeding at a rate of 0.1 mL/min.
Another approach is colonoscopy, which may be not only diagnostic, but through the use of endoscopic hemostasis, also therapeutic. In most circumstances, endoscopy is more accurate than arteriography or scintigraphy.
Controversy in the literature remains as to whether scintigraphy, angiography, or colonoscopy, and in which order, should be the initial diagnostic procedure of choice in the evaluation of lower GI bleeding.678 and 9 Thus, these decisions are often based on local availability and consultant preference.
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