Acute colonic diverticular haemorrhage: MSCT diagnosis

JBR–BTR, 2008, 91: 22.

IMAGES IN CLINICAL RADIOLOGY

Acute colonic diverticular haemorrhage: MSCT diagnosis B. Coulier1, Ph. Maldague2 A 76-year-old woman presented to the emergency room for recurrent episodes of acute rectorrhagy. The patient has a haemoglobin level at 100 g/l (n.v. 120-160) at admission. Gastroscopy was negative but sigmoidoscopy demonstrated fresh blood in the sigmoid colon; this active bleeding was too abundant to allow valuable results about its origin. A complete abdominal contrast-enhanced msCT was obtained at the arterial phase and without any gastrointestinal opacification to search for active bleeding; active intraluminal extravasation of iodine contrast was clearly demonstrated at the level of a posterior transverse colonic diverticulum (Fig. A, B -MIP projection-, C -VR view-) and this active bleeding was also confirmed by the rapid wash-out of the bleeding diverticulum on delayed views (Fig. D). No other potential cause of bleeding was detected on arterial and delayed portal scans. The patient was treated conservatively and the bleeding stabilized. A complete colonoscopy was achieved six days later confirming the colonic diverticulosis and ruling out all other potential causes of haemorrhage.

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Comment

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Acute gastrointestinal (GI) bleeding remains a common medical emergency and is still associated with substantial patient morbidity and mortality despite advances in diagnostic and therapy. Classical diagnostic modalities used for the detection of GI bleeding include upper GI endoscopy, colonoscopy, enteroscopy, radionuclide imaging, angiography and more recently capsule endoscopy. During the last decade, mdCT has considerably progressed in terms of performances and availability and recent studies have shown that arterial phase contrast-enhanced mdCT was rapid, safe, minimally invasive and accurate in detecting and localizing sites of bleeding in patients presenting with acute gastrointestinal bleeding; with angiography as reference standard a sensibility up to 90.9% and a specificity up to 99% have been reported. After exclusion of bleeding of the upper GI by endoscopy that remains the primary diagnostic modality, abdominal msCT angiography can easily be performed in an emergency without any preparation; it is more quickly available than colonoscopy, radionulide imaging and angiography and can also overcome the difficulties posed by emergency unprepared colonoscopy failing in 32% of cases in detecting bleeding lesions of lower GI tract. The high sensibility of msCT can be explained by the fact that it not only shows contrast extravasation itself and/or vascular abnormalities but can also demonstrate indicative morphologic change of the GI tract such as contrast enhancement of the bowel wall, focal perivisceral fat stranding or directly reveal the nature of the responsible anatomic lesion itself (polyp, tumor, diverticulum). MsCT angiography can not only accurately replace classical diagnostic angiography in most cases but the visualisation of contrast material extravasation on msCT scan can help interventional radiologists – in the perspective of transcatheter therapy – to direct the performance of more selective and supraselective investigations of arteries that are most likely to be bleeding. From a technical point of view, when msCT angiography is required for the diagnosis of acute intestinal bleeding, any contrast material or water administration in the gastrointestinal tract should absolutely be avoided; additional portal phase scans also appear particularly useful in determining more accurately the cause of acute GI bleeding especially in cases of tumor.

Department of 1. Diagnostic Imaging and 2. Gastroenterology, Clinique St Luc, Bouge (Namur), Belgium.