What are the benefits of CTA) for the diagnosis of lower gastrointestinal (GI) bleeding (LGIB)?

Updated: Jul 26, 2019
  • Author: Burt Cagir, MD, FACS; Chief Editor: BS Anand, MD  more...
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Jacovides et al demonstrated that preceding a visceral arteriography (VA) with CTA in diagnostic imaging for acute LGIB improved positive localization of the bleeding site compared with VA alone. [38] An increased use of CTA preangiography imaging may have the potential to reduce the number of overall imaging studies while also potentially increasing the positive yield at VA. [38] Preceding angiography with CTA had similar sensitivity and specificity to those of nuclear scintigraphy, but CTA localized bleeding sites with more precision and consistency with angiography findings. Moreover, CTA as a preangiography study reduced the overall number of imaging studies required and led to a greater overall contrast load without worsening the renal function when compared with nuclear scintigraphy. [38]

A retrospective, single-center study that compared CTA with tagged red blood cell (RBC) scintigraphy in the overall evaluation and management of acute LGIB revealed no significant differences between the two modalities with relation to patients' average hospital length of stay, blood transfusion requirements, incidence of acute kidney injury, or in-hospital mortality. [39] However, CTA accurately localized active bleeding at a significantly higher proportion than RBC scintigraphy scanning (53% vs 30%, respectively; P = 0.008). [39]

CTA appears to be less invasive and have a higher diagnostic yield over digital subtraction angiography (DSA) for the diagnosis of major obscure GI bleeding. [40] In a prospective, single-blind, single-center study that compared the diagnostic yield of CTA to that of DSA for major obscure GI bleeding in 24 patients, CTA identified an actively bleeding or a potential bleeding lesion over three times more than DSA (92% vs 29%, respectively; P<0.001) as well as identified active bleeding in twice as many patients as DSA (42% vs 21%, respectively; P = 0.06). [40]

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