Xenon CT and perfusion MRI in cerebral gliomas

Within certain limits the vascularity of cerebral gliomas correlates with d ysplasia. Xenon CT and perfusion MRI can be used to investigate tumor vascu larity. Using an optimized wash in/out protocol with inhalation of 30% xeno n gas, xenon CT was performed and regional cerebral blood flow (rCBF) and b lood/tissue partition coefficient (lambda) calculated. Furthermore, perfusi on MRI was performed using a dynamic T2*w EPI sequence with intravenous adm inistration of Gd-DTPA. The relative regional cerebral blood volume, arriva l time, time to peak and mean transit time were calculated. Both modalities were used in patients with supratentorial gliomas and compared with conven tional contrast-enhanced MRI (ceMRI). Calculation of regional cerebral bloo d flow, as compared to ceMRI, did not contribute to the diagnostic approach of tumor dysplasia. Tumour vascularity was better estimated by measurement of lambda. Measurement of relative regional cerebral blood volume also cor related with tumor vascularity. Mainly the possibility of direct quantifica tion of the Xe-CT data was advantagenous compared to perfusion MRI, and the XeCT data could be interpreted more clearly. Further upgrades of the techn ical equipment of MR as well as upgrades of available software will increas e the applicability of perfusion MRI. However, both modalities offer a more precise investigation of tumor vascularization compared to ceMRI since pot ential dysplastic alteration may be detected earlier, which will be advanta geous for planning bioptical approach of such tumours.