Usefulness of Cerebral Computed Angiotomography for Screening of Moyamoya Disease

Moyamoya disease has been diagnosed only by cerebral angiography, demonstrating occlusion or stenosis of the carotid bifurcation and abnormal vascular network (Moyamoya vessels) in the basal cistern extending to the basal ganglia. Recently, howeveresing high resolution CT scanner (GE • CT/T 8800), biplane cerebral computed angiotomography with rapid intravenous bolus injection of contrast agents has been made possible to visualize the specific features obtained by cerebral angiography on CT images. We reported a case of Moyamoya disease (unilateral), a 9-year-old boy with recurrent transient monoparesis of the right upper limb, which was initially diagnosed by this biplane cerebral computed angiotomography before carotid angiography. And this paper described also the intravenous minimum dose bolus (MinDB) injection method and biplane scanning projection for clear visualization of cerebral blood vessels, and the specific diagnostic features of Moyamoya disease on CT images. Cerebral computed angiotomographic features of Moyamoya disease were as follows: -In the axial plane, linear structures of the anterior half of the circle of Willis and proximal portion of the middle cerebral arteries were hardly identified, although the irregular tortuous or patchy high density areas just like “ca-terpillar” were visualized in the basal cistern and medial Sylvian fissures. -In the modified coronal plane, supraclinoid internal carotid arteries and proximal portions of anterior and middle cerebral arteries were hardly identified, while the abnormal “nebular” high density areas corresponding Moyamoya vessels were visualized in the basal cistern extending to the basal ganglia. Considering the vascular bed and its iodine concentration (more than 15 mg/ml) of intravascualr components, the modified coronal plane and the MinDB injection method (60% Conray® 1 ml/kg, 2ml/sec injection speed) seemed to be useful for visualization of these specific features. In our experience of this child case, it was concluded that cerebral computed angiotomography can serve as a noninvasive method for the screening or follow up study of Moyamoya disease.