CT perfusion assessment of Moyamoya syndrome before and after direct revascularization (superficial temporal artery to middle cerebral artery bypass).

<bold>Purpose: </bold>To evaluate the utility of CT perfusion (CTP) for the assessment of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in patients with Moyamoya syndrome (MMS).<bold>Subjects and Methods: </bold>Twenty-four consecutive MMS patients, who underwent unilateral STA-MCA bypass surgery, received CTP before and after surgery. The relative perfusion parameter values of surgical hemispheres before treatment were compared with post-treatment values. All patients underwent CT angiography (CTA) before and after surgery in order to confirm the patency of bypass.<bold>Results: </bold>The follow-up CTA after surgery clearly demonstrated 20 (20/24, 83.3 %) bypass arteries, whereas four (16.7 %) bypass arteries were occluded or very small. Postoperative rMTT and rTTP values (P < 0.05) of the surgical side were significantly lower than pre-operation. In patients (n = 20) with bypass patency, postoperative rCBF, rMTT and rTTP values (P < 0.05) of the surgical side were significantly improved. However, the differences of all parameters were not significant (P > 0.05) in the patients (n = 4) without bypass patency after revascularization.<bold>Conclusion: </bold>This study demonstrates that CTP can provide a crucial quantitative assessment of cerebral haemodynamic changes in MMS before and after STA-MCA anastomosis.<bold>Key Points: </bold>Twenty-four MMS patients undergoing STA-MCA bypass received CTP pre- and post-surgery. Cerebral haemodynamics improved on the surgical side post-surgery on CTP maps. rCBF might have a better correlation with patency of the bypass artery. CTP can evaluate cerebral perfusion changes in MMS patients after cerebral revascularization. [ABSTRACT FROM AUTHOR]