In aortic dissection (AD), CT angiography (CTA) is useful both in initial diagnosis and long term follow-up. In this study, we used CTA to evaluate the morphologic changes of aorta after AD.

We reviewed the initial and follow-up CTA images of 43 patients with AD. The diagnoses were double-lumen dissection (n=13), intramural hematoma (n=11), and residual dissection after surgery (n=19). The duration of CTA follow-up was 3.3±1.9 years (range 7 - 89 months). After reviewing the CTA images of the thoracic aorta level, and of the upper and lower abdominal aorta levels, we compared the areas of total lumen, true lumen and false lumen and the area ratio of true/total lumen.

Changes in luminal areas were greatest in the thoracic aorta, where both the true lumen area and the ratio of true/total lumen area increased. Subgroup analysis revealed that although the total lumen area increased significantly in the classic AD group, no changes were noted in the ratio of true/total lumen area. Only the increase in false lumen area (from 5.8 cm² to 9.0 cm²) was significant (p=0.036). In patients with intramural hematoma, a decrease in total lumen area and an increase in the ratio of true/total lumen area were noted.

In classic AD, false lumen dilatation occurs with false lumen enlargement, whereas in intramural hematoma total aorta size decreases with any increase in the ratio of true/total lumen area.