Noninvasive Tumor Grading of Glioblastomas Before Surgery Using Arterial Spin Labeling. A Cohort Study

To assess the clinical value of using arterial spin labeling (ASL) technique preoperatively for non-invasive tumor grading in glioblastoma (GBM) patients.

Forty-nine patients with GBMs were selected, including 21 patients with high-grade gliomas and 28 patients with low-grade gliomas. ASL perfusion imaging was performed with GE Signa Excite HD 3.0 T MR scanning system (GE Healthcare). Relative cerebral blood flow (rCBF) and relative tumor blood flow (rTBF) were quantified in all patients. Statistical analysis was performed with STATA version 12.0 software. Further, relevant human cohort studies published in Chinese and English languages were identified by database searches and screened. Data was extracted and meta-analysis was performed using Comprehensive Meta-analysis version 2.0 software.

The ratios of rTBF to rCBF in the contralateral white matter, contralateral gray matter, and contralateral hemisphere of high-grade gliomas were higher than low-grade gliomas (all p < 0.05). ASL results in the solid tumors revealed that rCBF was greater in high-grade gliomas. Such differences in rCBF were not significant (p > 0.05) when 2 and 5 cm distances from tumor margin were compared. Importantly, rCBF values showed statistical differences when the 2 cm distance was compared with the 5 cm distance from tumor margin (all p < 0.05). Finally, meta-analysis results supported the conclusion that rCBF and rTBF values were significantly higher in high-grade GBM as compared to low-grade GBM.

We present convincing data that ASL is highly effective in differentiating between high-grade and low-grade gliomas, and thus is a useful tool for preoperative evaluation of GBM.