[Diagnosis of aortic arch aneurysm--a case report of the utility of MR imaging].

We reported a case of syphilitic aortic arch aneurysm, which was examined by IADSA, X-ray CT and MR Imaging. A large aneurysm with the thick mural thrombus and central narrow lumen was clearly shown by MR Imaging. MR Imaging is an useful modality for the diagnosis of the aortic arch aneurysm with a very narrow lumen, which cannot be easily pointed out by IADSA.