Multidetector CT in the Evaluation of Thoracic Aortic Disease

C omputed tomography angiography (CTA) of the thoracic aorta has benefited greatly from the advent of multidetector computerized tomography (MDCT). Three-dimensional reconstruction of large datasets allows easy evaluation of pathological changes of the aorta. This improvement coincides with changes in treating thoracic aortic aneurysms (TAAs) because accurate preoperative assessment is critical to the early and late success in thoracic endovascular aortic repair (TEVAR). This article provides an overview of CTA of the thoracic aorta. The choice of imaging modality is diverse when thoracic aortic pathology is suspected. Choosing the right study to image the affected area requires an understanding of the anatomy and the limitations of the modality, as well as the clinical scenario of presentation. Common indications for thoracic aortic CTA are shown in Table 1. As carotid stenting has increased in popularity, the value of thoracic CTA has been shown. Arch evaluation with MDCT reduced the need for “unusual” maneuvers during stent placement in patients who underwent CTA of the thoracic aorta prior to carotid stenting. Recently, direct planimetric measurement of the aortic valve regurgitant orifice area in the diastole using 64-slice MDCT was shown to provide an accurate, noninvasive technique for detecting and quantifying aortic regurgitation.1 MDCT has also been shown to provide aortic valve area in addition to ejection fraction and coronary artery anatomy.2