Multisclice CT in Pulmonary Embolism

Abstract

Pulmonary embolism (PE) is an elusive disease of protean nature with a high incidence and mortality. Its diagnosis remains challenging — to this day an estimated 50% of fatal cases of PE are not diagnosed antemortem [1]. Recent years have seen an increasing importance of computed tomography (CT) in the diagnosis of PE, mainly brought about by the advent of fast CT image acquisition techniques [2–4]. Competing imaging modalities are in decline: Nuclear scanning, once the first line of defense in the diagnostic algorithm of PE, is withdrawing to diagnostic niches due to limited availability and a notorious lack of specificity [5]. The one-time gold standard for the diagnosis of PE, pulmonary angiography, is becoming increasingly tarnished [6,7]. Magnetic resonance (MR) imaging may be a promising tool for the diagnosis of PE [8,9] in the future but to date has not found widespread use in emergency medicine mainly due to its long examination times and difficulties in patient monitoring. In contrast, CT has become established as a widely available [10], safe, cost-effective [11], and accurate modality for a quick and comprehensive [4,12] diagnosis of the pulmonary circulation and the deep venous system [13]. The evident advantages of CT for the diagnosis of PE have become further enhanced by the introduction of multislice CT (MSCT, Siemens SOMATOM Volume Zoom) technology. It is now feasible to acquire a 1-mm scan of the entire thorax within one breath-hold. Perceived limitations of CT for the depiction of peripheral emboli are thus overcome. In the following sections we will discuss the clinical impact of MSCT on the diagnostic algorithm of suspected PE.