Spiral CT of pulmonary hypertension and chronic thromboembolism

Pulmonary hypertension caused by chronic pulmonary embolism (PE) represents an uncommon, but severe and surgically curable complication of recurrent acute embolism. Because clinical signs might be silent or nonspecific, chronic PE requires imaging methods for diagnosis and treatment planning. Chest radiographic findings are usually nonspecific. Scintigraphy provides a high sensitivity for PE, but lacks anatomic resolution and sufficient specificity. Pulmonary angiography, albeit accurate, is an invasive procedure associated with low but still considerable morbidity and mortality. Thus, noninvasive methods are required. Most reliably in the diagnosis of acute and chronic PE, fast computed tomography (CT) techniques like spiral CT provide noninvasive means to detect and differentiate organized mural thrombi, as well as perfusion abnormalities and concomitant findings. Magnetic resonance imaging offers morphologic as well as functional information on lung perfusion and right heart function, but image quality needs improvement to be comparable with spiral CT. Thus, although spiral CT is recommended as the screening method for acute and chronic PE, magnetic resonance imaging might be the method of the future.