DIAGNOSIS OF MOYAMOYA DISEASE WITH MAGNETIC-RESONANCE ANGIOGRAPHY

Background and Purpose Present criteria for the diagnosis of moyamoya disease emphasize the use of conventional cerebral angiography as an i ndispensable requirement. However, magnetic resonance angiography (MRA ) is fast becoming a reliable diagnostic modality for occlusive cerebr ovascular diseases. The purpose of this study is to assess the accurac y of MRA compared with conventional angiography. Methods Thirty-nine p atients (23 children and 16 adults) with moyamoya disease confirmed by conventional angiography (78 side views) were examined with MRA (thre e-dimensional time-of-flight technique with a 256x256 or 256x512 matri x). T-1- and T-2-weighted MR images were also taken. Results The steno tic or occlusive change at the carotid fork was clearly revealed by MR A, which correlated well with conventional angiography (83% good corre lation, 17% overestimation). Apparent moyamoya vessels were clearly sh own as a signal void on the MR image and fine unusual vessels on MRA, particularly in children with moyamoya disease (82%). However, small m oyamoya vessels were poorly shown on both MR images and MRA, particula rly in adults (63%). Conclusions MRA can be an alternative to conventi onal angiography in typical moyamoya disease cases (the bilateral type of moyamoya disease in children). However, in the early or the end st ages of moyamoya disease, diagnosis by means of MRA should be carefull y evaluated.