[MRA].

Abstract

With the recent development of MR techniques, it has become possible to obtain angiographic images (MRA) of relatively good quality with use of MR. The major indications of MRA have been to elucidate the MR findings on spin echo images when vascular lesions are suspected and to use MRA for conventional angiography when the latter is contra-indicated or additional information is needed. Follow-up studies of vascular diseases can be easily performed with MRA. The sensitivity of this technique for cerebral aneurysms is 73.6%, whereas specificity is 76.2%. The sensitivity and specificity for cerebrovascular diseases are 88.7% and 97.4% for stenoses of more than 50.0%. Because of rather limited diagnostic accuracy, this technique cannot be applied freely for screening of cerebral diseases, especially in mass survey for unruptured cerebral aneurysms. There have been many new techniques proposed for improvement of spatial resolution of MRA, including magnitisation transfer contrast (MTC), tilted optimized non-satulation excitation (TONE) and high resolution images. With full development of these new techniques, MRA will be used more freely in the diagnosis of vascular diseases.