Computed tomography in pre- and postoperative evaluation of aortic dissection.

Thirty-seven patients with angiographically or operatively confirmed acute, chronic or postoperative aortic dissection were examined by means of dynamic CT and the results compared with those obtained by angiography and ultrasonography (US). The diagnostic accuracy was 87 per cent for CT, 97 per cent for angiography, and 76 per cent for US, although US was only available in less than half of the cases. The highest accuracy (95%) of CT was achieved in the pre-operative group, which is comparable with the 97 per cent accuracy achieved using angiography. Three patients in the postoperative group had false negative CTs, resulting in an overall accuracy of 82 per cent as compared with 100 per cent for angiography. Despite its diagnostic capacity, CT could not define the complete extent of dissection in four patients. The descending thoracic aorta was the area most difficult for CT examinations because of frequent artifacts in the images.