PURPOSE: To assess the utility of spin-echo magnetic resonance(MR) imaging in the evaluation of thoracic and abdominal aortic aneurysm. MATERIALS AND METHODS: The spin-echo MR images of 27 aortic aneurysms in 22 patients were analyzed and correlated with angiography and/or operative findings retrospectively. Evaluations included location, type, and maximum diameter of the aneuyusm, mural thrombus, major branch involvement, and relationship with adjacent organ. RESULTS: The location of aneurysms was ascending thoracic aorta in seven cases, ascending thoracic aorta and aortic arch in one, descending thoracic aorta in six, thoracoabdominal aorta in three, and abdominal aorta in eight. Nineteen were fusiform, and eight were saccular. The mean of maximum diameters of the aneurysms was 7.9cm (4-10cm) on MR and 7.3cm (3-10cm) on angiography. Mural thrombus were noted in 13 cases on MR imaging and seven cases on angiograhpy. Angiography also underestimated the amount of mural thrombus. Eight cases involved major aortic branches. Although MR imaging and angiography were equal in the assessment of major abdominal aortic branches, MR imaging could not clearly demonstrate arch vessels, especially left subclavian artery, in aortic arch aneurysms. Among seven ascending thoracic aneurysms, six had aortic regurgitation. MR imaging showed left ventricular enlargement in all six cases. There was pericardial effusion in four cases which were noted only on MR imaging. MR imaging demonstrated hydronephrosis and renal atrophy in two cases of abdominal aortic aneurysms respectively. CONCLUSION: In the assessment of size of the aneurysm, mural thrombus, and relation with adjacent organs, MR imaging was better than angiography. MR and anglographic findings were equal in the assessment of the location and type of the aneurysm. Angiography was better than MR imaging in the assessment of major branch involvement, especially left subclavian artery.