Differentiation of Medulloblastoma Molecular Subtypes Using Multiparametric MRI and Texture Analysis

Background: Medulloblastoma is the most common pediatric malignant brain tumor in the population, with molecular subtypes that differ in prognosis and therapeutic response. Identifying these subtypes before surgery is important for tailoring management. Objective: This study aimed to distinguish medulloblastoma molecular subtypes using a combination of conventional MRI features and MRI based texture analysis. Materials and methods: We retrospectively analyzed 58 patients with preoperative MRI and histopathologic confirmation of medulloblastoma. Cases were classified into SHH pathway activated or Group 3/4 subtypes. Morphologic MRI characteristics, apparent diffusion coefficient (ADC) ratios, and texture analysis parameters were compared between the groups. Results: Of the 58 patients, 55.2% had SHH pathway activated tumors. Morphological features, including location out of the midline or in the cerebellar hemisphere (p<0.001), peritumoral edema (p=0.041), macrocysts (p=0.001), nodular involvement/lobulation (p=0.002), and heterogeneous contrast enhancement (p=0.002) were more common in SHH tumors. ADC measurements showed that the solid tumor-to-thalamus ratio was significantly lower in SHH tumors (p<0.001), with a threshold of 0.855 providing 82.1% sensitivity and 92.3% specificity. As for texture analysis parameters, kurtosis (p=0.023), SumOfSqs (p=0.022) and 01-10-50-90% percentile (p=0.011; p=0.001; p=0.006; and p=0.013 respectively) values obtained from ADC images and kurtosis (p=0.041), SumOfSqs (p=0.005), SumVarnc (p=0.014), SumEntrp (p=0.032) values obtained from T1W images were statistically significant in differentiating SHH and group 3/ group 4 medulloblastoma. Conclusion: Integrating MRI morphological features, ADC-based measurements, and texture analysis provides complementary information for non-invasive differentiation of medulloblastoma molecular subtypes.