Differentiation of glioblastoma and primary central nervous system lymphomas using multiparametric diffusion and perfusion magnetic resonance imaging

Abstract

The present study aimed to determine whether combining diffusion-weighted (DWI) and dynamic susceptibility contrast-enhanced perfusion-weighted (DSC-PWI) magnetic resonance imaging (MRI) could differentiate between primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). The present retrospective study evaluated 45 patients with histologically confirmed brain tumors, of which 18 had PCNSLs and 27 had GBMs. All patients underwent conventional, DWI, and DSC-PWI MRIs before the surgical removal of the lesion or stereotactic biopsy. The solid tumor component, peritumoral edema, and abnormal white matter were measured in three regions of interest to evaluate relative cerebral blood volume (rCBV), apparent diffusion coefficient (ADC) and DWI. In conventional MRI, there were significant differences in tumor numbers, tumor enhancement type, tumor necrosis, hemorrhage and open-ring sign between GBM and PCNSL. Solid tumor ADC and rCBV values (ADCt and rCBVt, respectively) and their ratios with abnormal white matter amounts were significantly higher in GBM cases than in PCNSL cases (P<0.05). The rCBV value for peritumoral edema (rCBVe) and its ratio with abnormal white matter amount (rCBVe/n) were significantly higher in GBM cases than in PCNSL cases (P<0.05). However, ADC values did not differ significantly for peritumoral edema. DWI values did not differ significantly. Combining rCBVt and rCBVe/n provided a perfect area under the receiver operating characteristic curve of 1.00, with 100% sensitivity and 100% specificity for distinguishing GBM from PCNSL. In the results of the present study, the major criterion in the decision-making process distinguishing PCNSL from GBM was the combined rCBVt and rCBVe/n parameter. A minor criterion was the ADCt value of the lesion.

Keywords: diffusion-weighted imaging; glioblastoma; lymphoma; perfusion-weighted imaging.

Figure 1

A 61-year-old woman with a GBM. (A) The MRI shows a mass (straight arrows) in the left frontal lobe. A comparison of (A) pre- and (B) post-contrast T1W images shows a heterogeneously enhanced tumor with central necrosis (curved arrows). (C) Axial FLAIR image shows peritumoral edema and infiltration. (D) The coronal T2W image with two manually drawn polygonal lines that include the entire peritumoral brain edema (blue line) and tumor (red line); the edema volume is ~equal to the tumor volume. (E) Hemorrhagic lesions (arrowhead) appear markedly hypointense on a conventional T2^* GE image. (F) Axial DWI and the corresponding (G) ADC map show a diffusion-restricted lesion within the enhanced tumor. (H) The color-coded CBV map shows higher vascularity in the normal white matter; three ROIs (circles) were placed in the solid tumor component (ROI 1), peritumoral region (ROI 2), and abnormal white matter (ROI 3). The minimum ADC was 0.84x10^-3 mm²/s in the solid tumor (ADCt), 1.14x10^-3 mm²/s in the peritumoral edema (ADCe), and 0.62x10^-3 mm²/s in the normal white matter (ADCn). The rCBV value was 7.62 in the solid tumor (rCBVt), 1.61 in the peritumoral edema (rCBVe), and 1.77 in the normal white matter (rCBVn). GBM, glioblastoma; MRI, magnetic resonance imaging; T1W, contrast-enhanced T1-weighted; FLAIR, fluid-attenuated inversion recovery; ADC, apparent diffusion coefficient; CBV, cerebral blood volume; ROI, circular regions of interest; ADCt, solid tumor ADC value; ADCe, peritumoral edema; ADCn, normal white matter; rCBV, relative cerebral blood volume; rCBVn, normal white matter rCBV value.

Figure 2

A 70-year-old man with a PCNSL. (A) The MRI shows a mass (straight arrows) in the right parietal lobe. A comparison of (A) pre- and (B) post-contrast T1W images shows a very strong and homogeneous open-ring enhanced tumor. (C) Axial FLAIR and (D) coronal T2W images with two manually drawn polygonal lines that include the entire peritumoral brain edema (blue line) and tumor (red line); the peritumoral volume is greater than the tumor volume. (E) The conventional T2^* GE image shows no intertumoral hemorrhage. (F) Axial DWI and the corresponding (G) ADC map show a diffusion-restricted lesion. (H) The CBV color map shows a lower signal intensity in the tumor than in the normal white matter; three ROIs (circles) were placed in the solid tumor component (ROI 1), peritumoral region (ROI 2), and abnormal white matter (ROI 3). The minimum ADC was 0.63x10^-3 mm²/s in the solid tumor (ADCt), 1.57x10^-3 mm²/s in the peritumoral edema (ADCe), and 0.69x10^-3 mm²/s in the normal white matter (ADCn). The rCBV value was 0.68 in the solid tumor (rCBVt), 0.54 in the peritumoral edema (rCBVe), and 0.37 in the normal white matter (rCBVn). PCNSL, primary central nervous system lymphoma; MRI, magnetic resonance imaging; T1W, contrast-enhanced T1-weighted; FLAIR, fluid-attenuated inversion recovery; DWI, diffusion-weighted; ADC, apparent diffusion coefficient; ADCt, solid tumor ADC value; ADCe, peritumoral edema ADC value; CBV, cerebral blood volume; rCBV, relative cerebral blood volume; rCBVt, solid tumor rCBV value; rCBVe, peritumoral edema rCBV value.

Figure 3

ROC curves of rCBV values for differentiating PCNSLs and GBMs. ROC curves are shown for rCBV values in the solid tumor (rCBVt; blue line) and peritumoral edema (rCBVe; yellow line) regions, and the ratio of peritumoral edema to normal white matter rCBV values (rCBVe/n; green line). The optimal cutoff values for rCBVt, rCBVe, and rCBVe/n were 4.15 (Se=100% and Sp=94%), 1.10 (Se=61% and Sp=93%), and 0.54 (Se=50% and Sp=96%), respectively. The AUCs for rCBVt, rCBVe, and rCBVe/n were 0.996, 0.782, and 0.751, respectively. ROC, receiver operating characteristic; rCBV, relative cerebral blood volume; PCNSL, primary central nervous system lymphoma; GBM, glioblastoma; rCBVt, solid tumor rCBV value; rCBVe, peritumoral edema rCBV value; rCBVe/n, the ratio of peritumoral edema to normal white matter rCBV values.

Figure 4

ROC curves of combined parameters for differentiating PCNSLs and GBMs. ROC curves are shown for rCBVt + rCBVe (green line), rCBVt + rCBVe/n (yellow line), rCBVe + rCBVe/n (yellow line), and rCBVt + rCBVe + rCBVe/n (orange line). Their AUCs were 0.998 (Se=100% and Sp=96%), 1.000 (Se=100% and Sp=100%), 0.800 (Se=78% and Sp=78%), and 1.000 (Se=100% and Sp=100%), respectively. ROC, receiver operating characteristic; PCNSL, primary central nervous system lymphoma; GBM, glioblastoma; rCBVt, solid tumor rCBV value; rCBVe, peritumoral edema rCBV value; rCBVe/n, the ratio of peritumoral edema to normal white matter rCBV values; AUC, area under the curve.