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. 2020 Jul 14;296(3):627–637. doi: 10.1148/radiol.2020192793

Figure 6:

Representative images in two patients with mild Moyamoya disease without impaired relative cerebral blood flow (CBF) change (rΔCBF) by using PET and a healthy control participant. Upper row: Case 4 shows a 29-year-old woman with mild left M1 stenosis (arrow). Both models successfully predict preserved rΔCBF in bilateral hemispheres, while rΔCBF measured with multidelay (MD) arterial spin labeling (ASL) (ASL rΔCBF) shows unexpected focal defect at right frontoparietal region. Middle row: Case 5 shows a 46-year-old man with bilateral internal carotid artery occlusion (double arrows) after bilateral bypass surgery. Baseline PET-CBF was preserved, but focal defects in CBF and mean ASL difference signal (mASL) of both ASLs, arterial transit artifact in MD-mASL CBF map (open arrowhead), prolonged arterial transit time (ATT) (*), and old infarct (open arrow) were observed in left anterior frontal region. Both models mistakenly predicted impaired rΔCBF in left anterior cerebral artery territory, probably due to previous bypass surgery. Lower row: Case 6 shows 28-year-old male healthy control participant with normal rΔCBF measured with PET (PET-rΔCBF). PD = proton density–weighted image, SD = single-delay, TOF-MRA = time-of-flight MR angiography.

Representative images in two patients with mild Moyamoya disease without impaired relative cerebral blood flow (CBF) change (rΔCBF) by using PET and a healthy control participant. Upper row: Case 4 shows a 29-year-old woman with mild left M1 stenosis (arrow). Both models successfully predict preserved rΔCBF in bilateral hemispheres, while rΔCBF measured with multidelay (MD) arterial spin labeling (ASL) (ASL rΔCBF) shows unexpected focal defect at right frontoparietal region. Middle row: Case 5 shows a 46-year-old man with bilateral internal carotid artery occlusion (double arrows) after bilateral bypass surgery. Baseline PET-CBF was preserved, but focal defects in CBF and mean ASL difference signal (mASL) of both ASLs, arterial transit artifact in MD-mASL CBF map (open arrowhead), prolonged arterial transit time (ATT) (*), and old infarct (open arrow) were observed in left anterior frontal region. Both models mistakenly predicted impaired rΔCBF in left anterior cerebral artery territory, probably due to previous bypass surgery. Lower row: Case 6 shows 28-year-old male healthy control participant with normal rΔCBF measured with PET (PET-rΔCBF). PD = proton density–weighted image, SD = single-delay, TOF-MRA = time-of-flight MR angiography.