ADC is not reliable in determinating subtypes of meningiomas

ObjectiveTo verify the reliability of apparent diffusion coefficient (ADC) measurements in determining subtypes of meningiomas.Material and methodsThirty patients (20 women and 10 men; average age, 53±15 years) with meningiomas were prospectively studied using DWI with b values of 0 and 1000. ADC values of the neoplastic tissue were obtained as the mean of measurements from three regions of interests within the mass and compared with histologic subtypes using ANOVA test (SPSS16).ResultsThe meningothelial subtype was found in 15 (50%) patients, fibroblastic in 10 (33.33%) patients and cystic in 5 (16.67%) patients. All meningiomas belonged to the WHO Grade 1 — benign meningiomas. There was no significant statistical difference between meningothelial, fibroblastic and cystic meningiomas when considering mean ADC values (0.000411+/−0.000066 mm2/s vs. 0.000750+/−0.001045 mm2/s vs. 0.000688+/−0.000063 mm2/s (p>0.05). Perifocal edema was present only with fibroblastic meningioma with mean ADC 0.000683 mm2/s. The ADC of the cystic component was statistically significantly higher in cystic meningeomas (0.001283 mm2/s) compared with fibroblastic (0.000224 mm2/s) and meningothelial meningiomas (0.000088 mm2/s) (p<0.001). The ADC of meningiomas was higher compared with contralateral healthy brain tissue (0.000642 mm2/s vs. 0.000404 mm2/s; n.s).ConclusionADC measurement do not seem reliable in identifying histological subtypes of Grade I meningiomas.