Intra-abdominal sepsis: the role of radiology

A wide range of imaging tools is available for the investigation of abdominal sepsis. Plain films and barium studies alone are generally regarded as inadequate and most patients will require ultrasound, CT or nuclear medicine studies to locate the source of sepsis. The choice of imaging modality depends on several factors, most important of which are the clinical condition of the patient and the presence or absence of localizing signs and symptoms. Ultrasound has the advantage of being portable and is therefore probably the best initial imaging method for the critically ill patient. It should also be the first investigation in patients with signs and symptoms localizing to the right upper quadrant, renal areas, subphrenic spaces or pelvis. Transvaginal ultrasound is particularly useful in examining the pelvis. CT is the imaging modality of choice for the pancreas and retroperitoneum and in patients who are poor candidates for ultrasound or in whom visualization on ultrasound is inadequate. In patients with PUO or evidence of sepsis without localizing signs or symptoms, nuclear medicine studies in the form of 67Ga citrate or labelled white cell scans are useful to localize the septic focus, although in most cases CT or ultrasound will subsequently be required for detailed anatomical definition. Imaging techniques have an increasingly important role to play in the treatment of sepsis, and guided aspiration and drainage may be performed with a high degree of accuracy under ultrasound or CT guidance, eliminating the need for surgical intervention in many individuals.