DOI: 10.1148/radiol.2461070434
(Radiology 2008;246:336.)
© RSNA, 2008
Multidetector CT of Acute Gastrointestinal Bleeding
Shuvro H. Roy-Choudhury, MBBS, FRCS, FRCR * and
Sharad Karandikar, MS, FRCS(Ed), FRCS(Gen Surgery) 
Department of Radiology* and Department of General Surgery, Heart of England NHS Foundation Trust, Birmingham Heartlands Hospital, Bordesley Green East, Birmingham B9 5SS, England
e-mail: shuvrorc{at}googlemail.com
Editor:
We congratulate the authors for the well-structured clinical study presented in the article "Acute Massive Gastrointestinal Bleeding: Detection and Localization with Arterial Phase Multi–Detector Row Helical CT" (1), which was published in the April 2006 issue of Radiology. Given the results of this preliminary study, multidetector computed tomography (CT) could well become the first investigation in acute lower gastrointestinal bleeding.
In the setting of acute lower gastrointestinal bleeding, we find multidetector CT a useful triaging tool to (a) obviate a negative angiographic finding, (b) localize the site of bleeding, (c) make the choice between surgery and embolization as the next treatment, (d) learn about abnormal vascular anatomy that may preclude or modify the approach to angiography, and (e) get additional information about the pathologic condition and prognosis of the cause of bleeding. Contrary to traditional thinking, provided that resuscitory support is ongoing, CT actually reduces the time to find a bleeding source and prevents time-consuming vessel cannulations at angiography.
The authors reported their sensitivity and specificity with digital subtraction angiography (DSA) as their reference standard. Although it is entirely appropriate to do so, there is reason to question DSA as a reference standard unless the study is highly superselective.
First, as suggested by the authors, bleeding can stop and start, even from minute to minute (2) owing to tamponade, spasm, or thrombosis. Second, in an in vitro study using a physiologic phantom, we showed that, like for like, multidetector CT is more sensitive than first-order aortic branch cannulation DSA (3). Multidetector CT had a lower threshold of depicting active bleeding (0.35 mL/min) compared with DSA (0.96 mL/min). In a study on a swine colon (4), similar lower sensitivities were reported. This principle has been borne out in our clinical experience by anecdotal cases. Therefore, the false-positive cases reported here could well have been below the threshold for detection at standard DSA.
On the basis of the emerging evidence about the sensitivity of multidetector CT in the detection of acute gastrointestinal bleeding beyond the ligament of Trietz, we are probably heading for a paradigm shift in the management of these cases. This is fortuitous, as multidetector CT is a more easily available investigation. There is one caveat to this approach though–an experienced angiographer occasionally relies on signs other than active extravasation or false aneurysms to perform embolization that may not be apparent at multidetector CT.
This is an important study that supports the use of multidetector CT in the management of acute gastrointestinal bleeding and we congratulate the authors for portraying it so clearly.
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References
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- Yoon W, Jeong YY, Shin SS, et al. Acute massive gastrointestinal bleeding: detection and localization with arterial phase multi-detector row helical CT. Radiology 2006;239(1):160–167.[Abstract/Free Full Text]
- Sos TA, Lee JG, Wixson D, Sniderman KW. Intermittent bleeding from minute to minute in acute massive gastrointestinal hemorrhage: arteriographic demonstration. AJR Am J Roentgenol 1978;131(6):1015–1017.[Abstract]
- Roy-Choudhury SH, Gallacher D, Rankin S, Woodburn P, Steers J, Adam A. Multislice CT (MSCT) versus digital subtraction angiography (DSA): sensitivity and lower limit of detection of active bleeding in a phantom [abstr]. In: Radiological Society of North America Scientific Assembly and Annual Meeting Program. Oak Brook, Ill: Radiological Society of North America, 2005; 228.
- Kuhle WG, Sheiman RG. Detection of active colonic hemorrhage with use of helical CT: findings in a swine model. Radiology 2003;228(3):743–752.[Abstract/Free Full Text]
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