PURPOSE--Comparative and prospective evaluation of three methods (transthoracic echo-Doppler (TTE), computerized tomography (CT) and aortography (AORT) utilized for aortic dissection diagnosis. METHODS--The 39 patients with confirmed aortic dissection (surgery or autopsy) underwent, within a few hours of each other, all three methods scrutinized. There were 19 cases of type A and 20 of type B dissection. RESULTS--In type A dissection the methods were equivalent (TTE = 73.7//, CT = 84.2//, AORT = 73.7//p = NS) but for type B, TTE was significantly inferior to the other two methods (TTE = 60//, TC 90//, AORT = 80//, p < 0.05 for TTE, for TC and AORT p = NS). In three occasions, even though all three methods were performed, the diagnosis was not obtained. CONCLUSION--The methods which were evaluated make the diagnosis in the majority of cases. In type A all methods are similar, however, in type B, TC and AORT are superior to TTE. Even performing all three methods in each patient, in three instances the diagnosis was not made