Discriminating high-grade from low-grade infratentorial tumors with non-contrast computed tomography attenuation of the solid part

Background To find a more general imaging method for preliminary grading of infratentorial brain tumors. Purpose To investigate the value of non-contrast computed tomography (NCCT) attenuation of the solid part of a tumor (SP-T) in distinguishing high- and low-grade infratentorial tumors. Material and Methods This retrospective study included 196 patients with primary infratentorial tumors. A total of 56 patients also underwent magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI). CT attenuation of SP-T, caudate nucleus (normal gray matter), and centrum semiovale (normal white matter) were measured. CT attenuation ratios of SP-T to normal gray matter (R T−G ) and normal white matter (R T−W ) were calculated. Each parameter was compared, and the area under the receiver operating characteristic curve (AUC) was used to determine diagnostic efficacy. Diagnostic efficacy of apparent diffusion coefficient (ADC) value and CT-related parameters were compared in 56 patients with both NCCT and MRI with DWI. Results There were significant differences ( P < 0.001) in mean CT attenuation of SP-T (35.32 ± 8.19 HU vs. 42.91 ± 5.56 HU), R T−G (0.95 ± 0.21 vs. 1.17 ± 0.15), and R T−W (1.37 ± 0.33 vs. 1.74 ± 0.30) between low- and high-grade infratentorial tumors. The AUCs for differentiating low-grade from high-grade tumors are 0.783, 0.819, and 0.797 for CT attenuation of SP-T, R T−G , and R T−W , respectively. For 56 patients with DWI, the AUCs for CT attenuation of SP-T, R T−G , R T−W , and ADC value were 0.833, 0.887, 0.850, and 0.910, respectively. All three CT-related parameters were not significantly different from the ADC value. Conclusion NCCT can distinguish low- and high-grade infratentorial tumors simply and conveniently and CT-related parameters show no significant difference compared to ADC value.