Differentiating between adult intracranial medulloblastoma and ependymoma using MRI

Abstract Purpose It is difficult to distinguish between adult intracranial medulloblastomas and ependymomas because of their overlapping imaging manifestations. However, considering their different treatments and prognoses, accurate preoperative differential diagnosis is essential. This study aimed to investigate the value of routine magnetic resonance (MR) examination combined with diffusion-weighted imaging (DWI) in the differential diagnosis of adult intracranial medulloblastomas and ependymomas. Materials and Methods MR images of 18 medulloblastomas and 18 ependymomas in adult patients were retrospectively analyzed, and differences in MR features of lesions and apparent diffusion coefficient (ADC) of solid lesions between the two groups were recorded. Independent sample t-tests and χ2 tests were used to analyze the differences in MR signs and maximum ADC (ADCmax), minimum ADC (ADCmin), and mean ADC (ADCmean) values between the two groups. The receiver operating characteristic (ROC) curve was used to determine the differential diagnostic efficacy and optimal threshold for each ADC value. Results There were significant differences in age and tumor enhancement between adult medulloblastoma and ependymoma (P < 0.05). The ADCmax (0.69 ± 0.11 vs. 1.04 ± 0.20×10− 3 mm²/s, P < 0.001), ADCmin (0.57 ± 0.12 vs. 0.96 ± 0.21×10− 3 mm²/s, P < 0.001), and ADCmean (0.62 ± 011 vs. 1.00 ± 0.20×10− 3 mm²/s, P < 0.001) values were significantly lower in adult medulloblastoma than in ependymoma. The areas under the ROC curves of ADCmax, ADCmin, and ADCmean were 0.951, 0.957, and 0.966, respectively. The optimal ADCmean threshold was 0.75×10− 3 mm²/s, with a sensitivity of 88.9% and a specificity of 88.9%. Conclusion Routine MR imaging examination combined with DWI is helpful in differentiating between intracranial infratentorial medulloblastoma and ependymoma in adults.