CT of pulmonary thromboembolism

Conventional incremental CT has for many years been useful in the fortuitous diagnosis of pulmonary thromboembolic disease, allowing for visualization of both the central occluding thrombus and the pleuroparenchymal sequelae. Unfortunately, the slow data acquisition times precluded the inclusion of conventional CT in diagnostic algorithms for the diagnosis of this disease. The development and increasing availability of fast scanning techniques, namely helical (spiral) CT and electron-beam CT, now provide a noninvasive means of consistently and accurately demonstrating acute and chronic pulmonary arterial thrombus to the segmental level. CT has the added advantage over ventilation-perfusion scanning and pulmonary angiography of depicting unsuspected intrathoracic disease that may account for the patient's presenting illness.