MAGNETIC-RESONANCE ANGIOGRAPHY IN MOYAMOYA DISEASE

Spontaneous occlusion of the circle of Willis, i.e., moyamoya disease (MMD), is a clinical disease entity angiographically characterized by progressive and bilateral stenosis of the carotid bifurcation, with a hazy collateral network at the base or convexity of the brain. Althoug h the importance of computed tomography (CT) and conventional magnetic resonance (MR) imaging in diagnosing MMD has already been determined, conventional arteriography is still regarded as necessary for definit ive diagnosis. Magnetic resonance angiography (MR-A) is a very recent vascular imaging technique which allows noninvasive and direct imaging of vessels without the use of contrast medium. We present four pediat ric cases of MMD, evaluated by conventional angiography, CT, MR imagin g, and MR-A. Our data demonstrate that MR-A is successful both in allo wing detection of occlusive disease of the basal portion of the intern al carotid artery and large branch basal cerebral vessels and demonstr ating the collateral vessels at the base of the brain. As a noninvasiv e procedure, MR-A promises to become a valuable alternative to classic al angiography in the diagnosis of MMD.