Differentiation between germinoma and other pineal region tumors using diffusion-and susceptibility-weighted MRI

Abstract

Purpose: To evaluate the effectiveness of diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) for differentiation between germinoma and other pineal region tumors.

Method: This retrospective study consisted of 72 patients with pathologically proven pineal region tumors between January 2010 and August 2020. Tumors were classified as germinomas (40), non-germinomatous germ cell tumors (11) (NGGCT), pineal parenchymal tumors (10) (PPT), and other types of tumors (11). Visual scale score, ADC values and SWI intratumoral susceptibility signal (ITSS) score were analyzed and compared to histopathology data.

Results: The mean apparent diffusion coefficient (ADCmean) and minimum apparent diffusion coefficient (ADCmin) ratio of germinoma were significantly lower than NGGCT. ADCmean or ADCmin cut-off ratio of ≤ 1.48 or ≤ 1.32 allowed for discrimination between germinoma and NGGCT with sensitivity and specificity of 100 % and 63.6 %. An ADCmin cut-off ratio of ≥ 0.93 allowed for discrimination between germinoma and PPT with sensitivity and specificity of 60 % and 80.0 %. ADCmin cut-off ratio of ≤ 1.15 allowed for discrimination of germinoma from other types of tumors with sensitivity and specificity of 87.5 % and 54.5 %.

Conclusions: ADC ratio can differentiate germinoma from other types of pineal region tumors. Our initial results suggest that ITSS score was not significantly correlated with specific histology subtype.

Keywords: DWI; Diffusion-weighted imaging; Germinoma; MRI; Pineal region tumors; SWI; Susceptibility-weighted imaging.