MR imaging of the thoracic aorta in Marfan patients.

A characteristic shape of the ascending aorta has been reported in patients with Marfan syndrome. To evaluate the capability of magnetic resonance (MR) imaging to distinguish between marfanoid and other aortic aneurysms, 11 Marfan patients (group 1), eight patients with ascending aorta enlargement (group 2), and 20 normal subjects (group 3) had transverse and sagittal MR of the thoracic aorta. Aortic diameter was measured at the sinuses of Valsalva (SV), the caudal portion of the ascending aorta, the prearch region (PA), the middle arch, and the descending aorta. The ratio SV/PA was significantly greater (p less than 0.001) in group 1 compared with groups 2 and 3. The SV/PA in all Marfan patients exceeded 1.4 but was less than 1.3 in subjects of groups 2 and 3. Magnetic resonance imaging provides definitive measurements of aortic dimensions and is potentially the method of choice for establishing the diagnosis of aortic involvement in Marfan syndrome and monitoring the course of aortic enlargement.