Differentiation of Medulloblastoma Molecular Subtypes Using Multiparametric MRI and Texture Analysis

Background: Medulloblastoma, the most common malignant pediatric brain tumor, has distinct molecular subtypes that vary in prognosis and treatment response. Accurate preoperative identification of these subtypes is crucial for optimizing therapy. Objective: The aim of our study was to differentiate medulloblastoma molecular subtypes using multiparametric MRI, including MRI-based texture analysis. Materials and methods: Fifty-eight patients with preoperative MRI and histopathological diagnoses of medulloblastoma were included. The patients were divided into SHH pathway active and group 3/group 4 subtypes. Morphological MRI findings, ADC measurements, and texture analysis features were compared between the groups. Results: Of the 58 patients, 55.2% had SHH-active tumors. Morphological features, including location out of the midline or in the cerebellar hemisphere (p<0.001), peri-tumoral 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: Combining MRI morphological findings, ADC measurements, and texture analysis offers valuable diagnostic information for distinguishing medulloblastoma molecular subtypes.