Computed tomography of the abdomen in the critically ill

In one's attempt to arrive at the most accurate diagnosis in the critically ill, the selection of the most efficacious and rapid imaging modality can be problematic to clinicians, especially if the clinical presentation is confusing. The selection most often, is between US and CT. In general, US is advantageous in that it can be performed at bedside and is a faster and less costly examination. Its main disadvantages are interference from intestinal gaseous distention, restricted field of view from surgical dressings or wounds, and operator-dependence for accuracy. With the newer and faster CT scanners, CT is gaining an increasingly important role in the evaluation of the critically ill, despite the need for patient transport to the radiology department. It is more effective in displaying and localizing abnormalities and more helpful for drainage guidance than US. The potential benefit of CT should outweight the risk of transport of the unstable patient, and because of CT's high cost, appropriate timing of the study and expected diagnostic benefit should be taken into consideration. Norwood reported that CT was not positive for abscess prior to the eighth postoperative day, only 55% of examinations aided in or altered the pre-examination diagnosis, and more than 70% were of no benefit to the patient. An organized approach is essential in solving complex diagnostic problems if one is to enhance patient care and efficacious use of personnel and resources. This can be accomplished best by direct communication between clinicians and radiologists before and after the examination. Radiologists who understand the clinical problems and are familiar with all diagnostic modalities should be consulted for the selection of the modality best suited to answering the question at hand. Similarly, critically ill patients should benefit most if clinicians and radiologists review the examination results together in light of the clinical presentation for more accurate and meaningful diagnosis.