Diagnostic Efficacy of Perfusion Magnetic Resonance Imaging in Supratentorial Glioma Grading

Background

 Pre-operative glial brain tumor grading could determine the management. Perfusion weighted magnetic resonance imaging (PWMRI) is a promising modality for assessment and management of brain lesions.

Objectives

 In this study, we assessed the diagnostic efficacy of this method in the grading of supratentorial gliomas using 3 Tesla MRI.

Patients and Methods

 Using a 3 Tesla MRI unit, 35 (20 male, and 15 female) patients with glioma were examined one month before surgery. Imaging protocol was: 615 slices, field of view (FOV) 22 × 22 cm2 T1W spin echo: repetition time (TR) 500 -echo time (TE) 30 and (FOV) 22 × 22 cm2 T2W Turbo spin echo: TR 5000 -TE 90. Then 15 cc gadolinium was injected at the rate of 3cc/s and imaging was repeated with: TR: 2360 TE: 45, flip angle 90, band width 1346 echo planar imaging (EPI) 128 measurement 50. Mean transit time (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured at enhancing and edematous regions compared to contralateral white matter. Then, an appropriate biopsy was performed from different sites of the tumor during surgical excision. Standard hispathological examination that was assessed in a double-blinded manner, was considered as gold standard.

Results

 Patients’ tumor distribution was grade IV in 14 (40%), grade II in 14 (40%), grade III in six (17.1%) and grade I in one (2.9%). Relative CBF (rCBF), and rCBV was significantly more in high-grade glioma (HGG) versus low-grade glioma (LGG) (P < 0.001 and P < 0.009, respectively) and rCBF difference was more than rCBV but it was not significant. MTT was statistically the same in both groups and there was no difference between them. A value of rCBV greater than 2 showed a sensitivity of 90% and specificity of 67% and rCBF greater than 1.4 showed a sensitivity of 100% and a specificity of 74% in discrimination of high grade gliomas versus low grade gliomas.

Conclusion

 PWMRI is more accurate than conventional MRI for noninvasive discrimination of low-grade glioma (LGG) and high-grade glioma (HGG) that could be helpful for neurosurgeons in decision making dealing with the most common tumor of the brain.