Cerebral hemodynamics in Moyamoya disease: correlation between perfusion-weighted MR imaging and cerebral angiography

Abstract

Background and purpose: In Moyamoya disease, the relationship between cerebral hemodynamics and angiographic findings has not been fully evaluated. The purpose of this study is to evaluate hemodynamics in Moyamoya disease with perfusion-weighted MR imaging (PWI) and cerebral angiography.

Methods: Twenty patients with Moyamoya disease were the subjects. Mean transit time (MTT) derived from PWI was calculated in the medial frontal lobes, the posterior frontal lobes, the occipital lobes, and the basal ganglia. From the angiographies, we classified the degrees of internal carotid artery (ICA) and posterior cerebral artery (PCA) stenoses as well as the degrees of Moyamoya vessels and leptomeningeal anastomosis (LMA). MTT in each region was compared with the angiographic findings.

Results: MTT positively correlated with the degree of ICA stenosis in the medial frontal (P < .01), posterior frontal (P < .001), and occipital (P < .001) lobes, as well as in the basal ganglia (P < .001). MTT correlated with the degree of PCA stenosis in the medial frontal (P < .001), posterior frontal (P < .001), and occipital (P < .001) lobes, as well as in the basal ganglia (P < .001). MTT correlated with the degree of Moyamoya vessels in the medial frontal (P < .05) and posterior frontal (P < .01) lobes. A multivariate analysis revealed that ICA and PCA stenoses and Moyamoya vessels were independent factors that prolonged MTT.

Conclusion: Both ICA and PCA stenoses may influence overall cerebral perfusion in Moyamoya disease. The development of Moyamoya vessels may indicate hemodynamic impairment.

Fig 1.

Regions of interest drawn in a PWI (A) and MTT map (B). The regions of interest were placed on cortical regions in the medial frontal lobe in the ACA distribution, in the posterior frontal lobe in the MCA distribution and in the occipital lobes in the PCA distribution as well as in the putamen in each cerebral hemisphere. To calculate the MTTs in the frontal lobes, as well as in the basal ganglia, an AIF (blue dot) was obtained from an ipsilateral MCA branch to represent anterior circulation. In calculating MTT in the occipital lobe, an AIF (yellow dot) was obtained from an ipsilateral PCA branch. This MTT map (B) was calculated with the AIF obtained from the right MCA branch.

Fig 2.

A 10-year-old boy with Moyamoya disease who presented with weakness of the right upper extremity. Right internal carotid arteriogram in posterior-anterior projection (A) shows that the right proximal anterior cerebral artery is mildly stenotic (black arrow). No steno-occlusive change is found in the ICA or MCA. The right ICA is in stage 1. No Moyamoya vessels are seen. Left internal carotid arteriograms in posterior-anterior projection (B) show that the right distal ICA and the anterior and MCAs are occluded (white arrow). The left ICA is in stage 3. Marked Moyamoya vessels are seen, and peripheral branches of the anterior cerebral artery and MCA are opacified via the collateral vessels (black arrowhead). On the left vertebral arteriogram in posterior-anterior projection (C), no steno-occlusive change is found in the bilateral posterior cerebral artery. The bilateral posterior cerebral artery is in stage 1. Leptomeningeal collateral vessels from the left posterior cerebral artery to the anterior circulation are seen (white arrowhead). MTT map (D) shows the areas of prolonged mean MTT in the left frontal and temporal lobes. This map was calculated with the AIF obtained from a right MCA branch.

Fig 3.

A 45-year-old woman with Moyamoya disease who presented with right thalamic hemorrhage. Right internal carotid arteriograms in posterior-anterior projection (A) demonstrated that the right ICA, anterior cerebral artery, and proximal MCA are occluded (large black arrow). The right ICA is in stage 4. Slightly developed Moyamoya vessels are seen around the distal ICA (black arrowhead). The distal MCA is visualized through the Moyamoya vessels. Left common carotid arteriogram in lateral projection (B) shows that the left ICA is completely occluded in its proximal portion (white arrowhead). The left internal ICA is in stage 6. Left vertebral arteriogram in posterior-anterior projection (C) shows severe stenosis in the bilateral posterior cerebral arteries (white arrows). Moyamoya vessels are seen in the posterior region of the brain base. Peripheral branches of bilateral posterior cerebral arteries are visualized through Moyamoya vessels. The bilateral posterior cerebral artery is in stage 3. MTT map (D) demonstrates extensive areas of prolonged MTT in bilateral cerebral hemispheres. This map was calculated with the AIF obtained from a right MCA branch.