Diagnostic Accuracy of T1-Weighted Dynamic Contrast-Enhanced-MRI and DWI-ADC for Differentiation of Glioblastoma and Primary CNS Lymphoma

Abstract

Background and purpose: Glioblastoma and primary CNS lymphoma dictate different neurosurgical strategies; it is critical to distinguish them preoperatively. However, current imaging modalities do not effectively differentiate them. We aimed to examine the use of DWI and T1-weighted dynamic contrast-enhanced-MR imaging as potential discriminative tools.

Materials and methods: We retrospectively reviewed 18 patients with primary CNS lymphoma and 36 matched patients with glioblastoma with pretreatment DWI and dynamic contrast-enhanced-MR imaging. VOIs were drawn around the tumor on contrast-enhanced T1WI and FLAIR images; these images were transferred onto coregistered ADC maps to obtain the ADC and onto dynamic contrast-enhanced perfusion maps to obtain the plasma volume and permeability transfer constant. Histogram analysis was performed to determine the mean and relative ADC_mean and relative 90th percentile values for plasma volume and the permeability transfer constant. Nonparametric tests were used to assess differences, and receiver operating characteristic analysis was performed for optimal threshold calculations.

Results: The enhancing component of primary CNS lymphoma was found to have significantly lower ADC_mean (1.1 × 10^-3 versus 1.4 × 10^-3; P < .001) and relative ADC_mean (1.5 versus 1.9; P < .001) and relative 90th percentile values for plasma volume (3.7 versus 5.0; P < .05) than the enhancing component of glioblastoma, but not significantly different relative 90th percentile values for the permeability transfer constant (5.4 versus 4.4; P = .83). The nonenhancing portions of glioblastoma and primary CNS lymphoma did not differ in these parameters. On the basis of receiver operating characteristic analysis, mean ADC provided the best threshold (area under the curve = 0.83) to distinguish primary CNS lymphoma from glioblastoma, which was not improved with normalized ADC or the addition of perfusion parameters.

Conclusions: ADC was superior to dynamic contrast-enhanced-MR imaging perfusion, alone or in combination, in differentiating primary CNS lymphoma from glioblastoma.

Fig 1.

Area under the curve for apparent diffusion coefficient and blood plasma volume. Area under the curve for ADC_mean, rADC_mean, and rVp_90%tile demonstrating the highest AUC value for ADC_mean. There are no statistically significantly differences among the 3 AUCs.

Fig 2.

Glioblastoma. Axial FLAIR (A), contrast-enhanced T1-weighted (B), diffusion-weighted (C), ADC (D), permeability transfer constant (E), and plasma volume (F) images reveal a heterogeneously enhancing tumor in the right frontal lobe with peripheral diffusion restriction (low on ADC, D), increased leakiness (E), and increased perfusion (F). These findings suggest areas of cellular tumor with marked neovascularity and areas of necrosis. Micrographs (G and H) show high glial neoplasm with necrosis (G, arrows), microvascular proliferations (H, arrows), and mitotic activity (H, arrowhead), consistent with a diagnosis of glioblastoma. Magnification ×20 (G) and ×40 (H).

Fig 3.

Primary CNS lymphoma. Axial FLAIR (A), contrast-enhanced T1-weighted (B), diffusion-weighted (C), ADC (D), permeability transfer constant (E), and plasma volume (F) images show an enhancing tumor in the right frontal lobe with diffusion restriction (D), increased leakiness (high on K^trans, E), and only slightly increased perfusion (slightly high on Vp, F). These findings indicate cellular tumor without marked neovascularity, typical for primary CNS lymphoma. Micrographs (G and H) show high-grade lymphoid proliferation with obvious mitotic activity in the cytology preparation (H, arrowheads). Magnification ×40 (G and H).