Radiological investigation in acute diverticulitis.

Optimal management of acute sigmoid diverticulitis depends on evaluation of the severity of the inflammatory process, in which radiological investigation is a useful but probably underutilized adjunct to clinical assessment. Plain abdominal radiography shows abnormalities in 30-50 per cent of patients but these tend to be non-specific and more accurate information is obtainable from a contrast enema. Although the quality of images produced by a water-soluble contrast agent is inferior to that with barium, the former is less hazardous in the presence of perforation and provides sufficient information to permit rational management decisions to be made. Ultrasonography and computed tomography (CT) are particularly useful in visualizing abscesses. They may be helpful in following the progression or resolution of suppuration and in guiding percutaneous aspiration when appropriate. Despite early reports to the contrary, CT is no more specific than a contrast enema in the diagnosis of acute diverticulitis. Radionuclide scans have little role in the routine assessment of acute diverticulitis and magnetic resonance imaging has not been adequately evaluated. Water-soluble contrast enema is safe, widely available and probably the most useful early supplementary investigation.