TY - JOUR T1 - Distinguishing between Germinomas and Pineal Cell Tumors on MR Imaging JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 550 LP - 555 DO - 10.3174/ajnr.A2806 VL - 33 IS - 3 AU - N. Dumrongpisutikul AU - J. Intrapiromkul AU - D.M. Yousem Y1 - 2012/03/01 UR - http://www.ajnr.org/content/33/3/550.abstract N2 - BACKGROUND AND PURPOSE: Tumors of pineal cell origin have different prognosis and treatment than those of germ cell origin. The recent literature suggests that these tumors often look alike. Our study aimed to differentiate between pineal cell tumor and germinoma based on ADC values, the homogeneity of the mass, and MR imaging characteristics. MATERIALS AND METHODS: We enrolled 20 patients who had pretreatment MR imaging scans with histologic verification of tumors of pineal cell origin and germinomas. The tumors were measured for the ADC values and for homogeneity by the coefficient of variation of ADC values, and T1WI and T2WI signal intensity values. RESULTS: The 20 subjects (8 females and 12 males) ranged in age from 1.5–64.9 years, with a mean age of 23.9 years (SD 17.7 years). The mean age of those with germinomas was 13.7 years (SD 3.8 years), less than the mean of 29.4 years for those with pineal cell tumors (SD 19.9 years; P = .016). These 2 groups showed no significant difference in coefficients of variation on T1WI, T2WI, and ADC images. However, germinomas showed statistically significant higher ADC values (mean 1590.69 ± 532.96 × 10−6 mm2/s) than pineal cell tumors (mean 883.58 ± 317.48 × 10−6 mm2/s; P = .02). An accuracy of 89.5%, sensitivity of 83.3%, specificity of 92.3%, PPV of 83.3%, and NPV of 92.3% were yielded for an ADC threshold of 1250.00 × 10−6 mm2/s. CONCLUSIONS: Germinomas showed higher ADC values than the pineal cell tumors (P = .02), and the patients were younger. Otherwise, there were no definitive imaging characteristics that distinguished pineal cell tumors from germinomas. NPVnegative predictive valuePNETprimitive neuroectodermal tumorPPTIDpineal parenchymal tumor of intermediate differentiationPPVpositive predictive valuePTPRpapillary tumor of the pineal regionTR/TErepetition time/time-to-echoWHOWorld Health Organization ER -