To investigate the value of MRI combined with diffusion weighted imaging (DWI) in differential diagnosis between cerebellar pilocytic astrocytoma (PA) and hemangioblastoma (HB).

Twenty-two patients with PA and 23 patients with HB confirmed by pathology in Huai′an Cancer Hospital from January 2014 to March 2021 were collected. Imaging features of the tumors (large cysts with small nodules, solid, intracystic separation, empty blood vessels, homogeneous enhancement of solid part, enhancement of cyst wall, peritumoral edema) were analyzed. Apparent diffusion coefficient (ADC) values of the tumor parenchymal area and the contralateral normal reference area were obtained and then relative (tumor/reference) ADC (rADC) values were calculated. Imaging features and rADC values were compared between the two groups. Receiver operating characteristic curve (ROC) was used to analyze the efficacy of rADC value in differentiating PA and HB.

Age distribution of PA group was significantly lower than that of HB group (t=-8.28, P<0.01). Compared with PA, HB was more likely to show large cysts with small nodules, empty blood vessels and homogeneous enhancement of solid part (χ²=7.03, 13.93, 10.41, all P<0.01), while there were no significant differences in other imaging features (solid tumor, intracystic partition, enhancement of cystic wall, peritumoral edema) between the two groups (all P>0.05). The rADC value of HB group was significantly higher than that of PA group (t=-5.65, P<0.01), area under curve (AUC) of the rADC value differentiating the two groups was 0.892, and when the threshold was 1.64, the corresponding sensitivity and specificity were 82.60% and 81.80%, respectively.

Conventional imaging features can effectively distinguish Hb from PA, and rADC value can provide quantitative parameters for their differential diagnosis.