Comparison of conventional, diffusion, and perfusion MRI between infratentorial ganglioglioma and pilocytic astrocytoma.

The differentiation of infratentorial ganglioglioma and pilocytic astrocytoma may be therapeutically relevant, which is sometimes challenging to both pathologists and neuroradiologists.To evaluate the conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and dynamic susceptibility contrast-enhanced perfusion weighted imaging (DSC-PWI) features of infratentorial ganglioglioma compared with pilocytic astrocytoma.

This retrospective study enrolled 12 patients with infratentorial ganglioglioma and 61 patients with pilocytic astrocytoma who underwent MRI before surgery. DSC-PWI was performed in 20 patients (4 gangliogliomas, 16 pilocytic astrocytoma). Demographics, conventional imaging characteristics (tumor location, margin, cystic change, enhancement, peritumoral edema, and ipsilateral cerebellar atrophy), rADC_min, and rCBV_max ratio were compared. The optimum threshold, sensitivity, and specificity for rADC_min and rCBV_max ratios were determined.

Infratentorial ganglioglioma appeared similar to pilocytic astrocytoma but was more likely to have an ill-defined margin ( P = 0.035), ipsilateral cerebellar atrophy ( P < 0.001), lower rADC_min ratio (1.24 ± 0.27 vs. 2.04 ± 0.46, P < 0.001), and higher rCBV_max ratio (3.05 ± 1.12 vs. 1.64 ± 0.39; P = 0.008). The threshold values ≤1.66 for rADC_min ratio provide sensitivity and specificity of 91.67% and 77.05%, respectively, for discriminating ganglioglioma from pilocytic astrocytoma. The optimal threshold value for rCBV_max ratio was >1.64.

Conventional MRI, DWI, and DSC-PWI can help to differentiate infratentorial ganglioglioma from pilocytic astrocytoma. DWI offers optimal sensitivity.