It is difficult to distinguish solitary of fibrous tumor/hemangiopericytoma (SFT/HPC) from atypical meningioma (AM) by conventional imaging.As far as we know,diffusion weighting imaging may identify them effectively.The purpose of this study was to determine the role of apparent diffusion coefficient (ADC) values to distinguish and predict prognosis of solitary of fibrous tumor/hemangiopericytoma (SFT/HPC) (WHOII) and atypical meningioma (AM).Preoperative diffusion-weighted imaging (DWI) of 30 cases with histopathologic and immunhistochemical testified SFT/HPC WHOII (n= 11) and AM (n= 19) were performed retrospectively. The ADC values of lesion, peritumoral edema, normal white matter and lesion NADC ratio (lesion ADC values/ADC values of normal white matter (NWN ADC)) were compared. The immunhistochemical markers (Ki-67, CD34, Vim, EMA, GFAP, S-100, PR, CD56) were compared. The correlation between the ADC values and Ki-67 index was evaluated.The mean lesion ADC values of SFT/HPC (1.15 ± 0.04 × 10-3 mm2/s) was significantly higher than that of AM (0.80 ± 0.04 × 10-3 mm2/s) (t= 23.824, p< 0.05). The mean NADC ratio was lower for AM (1.03 ± 0.06) compared with SFT/HPC (1.51 ± 0.05) (t= 23.105, p< 0.05). The mean edema ADC for SFT/HPC (1.47 ± 0.06 × 10-3 mm2/s) was lower compared with AM (1.68 ± 0.05 × 10-3 mm2/s) (t=-9.926, p< 0.05 ). There was no statistical difference between the two groups of NWM ADC (t=-1.475, p> 0.05) . The mean Ki-67 of SFT/HPC (7.18 ± 2.60%) was lower than the mean Ki-67 of AM (13.58 ± 4.50%) (t=-4.934, p< 0.05). The CD34 showed statistically differences between two groups (X2= 13.659, p< 0.05). The EMA also showed statistically differences between two groups (X2= 4.474, p< 0.05). Vim,GFAP, S-100, PR, CD56 showed no statistical difference in the two group (p> 0.05). The pearson analysis indicated that there was a negative correlation between lesion ADC and Ki-67 in SFT/HPC group (r=-0.770, p< 0.05) and AM group (r=-0.727, p< 0.05). There was also a negative correlation between lesion NADC ratio and Ki-67 in SFT/HPC group (r=-0.673, p< 0.05) and AM group (r=-0.707, p< 0.05). There was a positive correlation between edema ADC and Ki-67 in SFT/HPC group (r= 0.819, p< 0.05) and AM group (r= 0.942, p< 0.05). Furthermore,there was no correlation between NWM A DC and Ki-67 in SFT/HPC group (r=-0.403, p> 0.05) and AM group (r= 0.202, p> 0.05).The lesion ADC, lesion NADC ratio and edema ADC can distinguish the SFT/HPC WHO II from AM and be helpful to predict prognosis of the two tumors before operation. Further more, histopathologic and immunhistochemical can make a definite diagnosis of the two tumors.
