Abstract
Recently the significance of MRI in the diagnosis of cerebrovascular disease has been recognized, and the findings of “Moyamoya Disease” have been reported utilizing strong magnetic field MRI scanner. In this paper we discuss the usefulness of MRI especially in the assessment of vascular abnormality in this disease.
At first, MRI and cerebral angiography in six cases of “Moyamoya Disease” were studied. The vascular diameter of cavernous portion in angiogram were compared with the degree of stenosis of that portion in MRI. There was good correlation between the degree of stenosis in angiography and that in MRI. Also MRI clearly revealed the stenosis or occlusion in the circle of Willis, and the development of “Moyamoya” vessel in basal ganglia.
Next, we examined the usefulness of fast scan, which is a new method obtaining the vascular enhanced image. In normal fast scan, images of each arteries of the circle of Willis such as terminal portion of ICA or proximal portion of ACA, MCA are constantly delineated in high intensity in contrast with brain parenchyma, skull bone, soft tissue, venous system, and CSF space which are visualized in low intensity in general. In the cases of “Moyamoya Disease”, each portion of the circle of Willis as well as cavernous portion of ICA showed stenotic change which are more clearly demonstrated in fast scan. And the development of “Moyamoya” vessels in basal cistern was also visualized in detail with good contrast. On the other hand, “Moyamoya” vessels in basal ganglia are not always visualized clearly.
As a result, vascular abnormality of “Moyamoya Disease” is evaluated finely and noninvasively in detail in MRI, and MRI is useful in screening and follow-up in this disease.
