High- and low-grade glioma differentiation: the role of percentage signal recovery evaluation in MR dynamic susceptibility contrast imaging.

Abstract

Evaluation of cerebral blood volume (CBV) with magnetic resonance (MR) imaging can differentiate low-grade from high-grade gliomas. The percentage of signal recovery (PSR) in the venous phase of perfusion curves is inversely proportional to blood-brain barrier (BBB) permeability. Since even BBB permeability relates to glioma malignancy grade, we carried out a comparative evaluation between CBV and PSR to characterise cerebral gliomas. Forty-nine patients with cerebral gliomas were studied with MR perfusion imaging. In all tumours, both maximum CBV and minimum PSR were calculated. The difference between the CBV and PSR mean values among the low-grade and high-grade gliomas was assessed using statistical methods. We also examined whether there was an additional difference between low-grade and grade III gliomas. Finally, CBV and PSR diagnostic sensitivity and specificity in identifying low-grade gliomas compared to all gliomas and low-grade gliomas compared to all gliomas excluding glioblastomas was assessed. A significant difference between low-grade and high-grade gliomas with both CBV and PSR was demonstrated. Conversely, there was a significant difference between low-grade and grade III gliomas only with PSR, while CBV did not show significant difference. Finally, superior sensitivity and specificity of PSR compared to CBV in identifying low-grade gliomas was demonstrated both compared to all gliomas and all gliomas excluding glioblastomas. The PSR evaluation proved better than CBV for determining the grade of brain and is therefore a useful tool to be considered in the MR evaluation of gliomas.