Failure of computer assisted tomography to detect experimental acute obstruction of major pulmonary arteries

Large perfusion defects were produced by total balloon occlusion of major branch pulmonary arteries in two baboons and one dog. The position and total occlusion were confirmed by pulmonary angiograms. Computer assisted tomography (CAT) failed to demonstrate any difference in the nonperfused segment of lung either before or after intravenous contrast injection.