Diagnostic approach of pulmonary embolism by spiral angioscanner

Abstract

Spiral volumetric computerized tomography (CT) allows the exploration of the whole chest during a single contrast injection and breath-hold. For the diagnosis of central pulmonary embolisms, the sensibility is between 78 and 98% and the specificity between 86 and 94% depending on the direct visualization of the endoluminal defect. Detection of intercurrent parenchymal pathologies or of non-obstructive arterial thrombi explain some false positive or inconclusive results of the ventilation-perfusion scintigraphy. Sub-segmental thrombi are less easily detected and sensibility for both central and sub-segmental embolisms is only 63%, explaining some rare false negatives of the CT on isolated sub-segmental embolisms. Chronic thrombi are outlying and contiguous with the arterial wall. They are associated with arterial stenosis, cut-off and loops and an oligemic mosaic pattern of the parenchyma. CT allows pre-operative staging before surgical recanalization and the intra-venous injection does not interfere with the arterial pressure. CT is a non-invasive, reliable and easily available technique which clearly plays an important role in the diagnosis of pulmonary embolism.