Tumour blood flow and partition coefficients: correlation with grade of cerebral gliomas using xenon-enhanced computed tomography.

It is possible to underestimate the grade of nonenhancing cerebral tumours on conventional contrast-enhanced MRI or CT. Differentiation of high- and low-grade gliomas by measurement of the brain-blood partition coefficient lambda (Tλ ) with Xe-enhanced CT (XeCT) has been reported. We assessed the practical applications of XeCT in suspected low-grade astrocytomas. We examined 15 patients with tumours which showed no contrast enhancement on conventional MRI and CT, using XeCT. Tumour blood flow (TBF) and Tλ were calculated. Fourteen patients underwent surgery, one patient had a biopsy. We recognised three histological groups. While Tλ differed significantly between them, TBF did not. Group 1 contained grade II–III astrocytomas and Tλ was 0.77; group 2 contained grade I–II astrocytomas with Tλ 1.14, and group 3 four oligodendrogliomas in which a Tλ of 1.50 was found.