Radiographics 2009; 29:791-804
Christine P. Chao, MD , T. Gregory Walker, MD , Sanjeeva P. Kalva, MD
Rupture of the vasa vasorum into the media of the aortic wall results in an aortic intramural hematoma. Characteristic findings of an aor¬tic intramural hematoma include a crescentic hyperattenuating fluid collection at unenhanced computed tomography (CT) and a smooth, nonenhancing, thickened aortic wall at contrast material-enhanced CT. The CT appearance of untreated intramural hematomas evolves over time, and decreased attenuation is a clue to the chronicity of a hematoma. CT is particularly useful for evaluating aortic intramural hematomas because it allows their differentiation from aortic dissec¬tions, which have similar clinical manifestations, and permits an exact determination of their location—crucial information for surgical plan¬ning. On the basis of CT findings, some hematomas may be expected to resolve spontaneously, whereas others may be identified as posing a high risk for serious complications such as aortic dissection, aneu¬rysm, and rupture. Appropriate clinical management is aided by accu¬rate recognition of diagnostically specific CT features and awareness of their significance.