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FIG 4. Parametric images of distribution of rCBV and TTP (A and B) and rR and TTP (C and D) in a patient (case 4) with minimal transient symptomatology. Angiogram shows only mild stenosis of the left internal carotid artery and that the right internal carotid artery was normal (internal carotid artery grade 1), but severe stenosis of the right posterior cerebral artery is shown with well-developed posterior cerebral artery moyamoya (posterior cerebral artery grade 3). Color coding is as described in the legend to Figure 3; Color charts explain color coding for each image type. Note the presence of abnormal areas of neovasculature (arrows) indicated by prolonged TTP, high rCBV, and abnormal prolongation of rR. The presence of moyamoya vessels was confirmed on digital subtraction angiograms. Distal to the abnormal vessels, a wedge-shaped area of prolonged TTP is seen; values of rR throughout this area are normal.
