Abstract
BACKGROUND: The differentiation of germinoma from other tumors can be very difficult. We evaluated the usefulness of advanced MRI for the differentiatial diagnosis of germinoma. MATERIALS AND METHODS: Our IRB approved this retrospective study. We reviewed the images of 26 patients with histologically confirmed germinoma who were treated in our institution between 2003 and 2016. We also studied 25 patients with pineal tumors which included 14 non-germinomatous germ cell tumors (NGGCT), 9 pineal parenchymal tumors (PPT) and 2 meningioma. Patients underwent CT and conventional MRI and advanced MRI including diffusion-weighted imaging (DWI) and/or arterial spin labeling based perfusion-weighted imaging and single voxel proton MR spectroscopy (1HMRS). RESULTS: In germinoma patients group, age ranged from 9.1 to 37.7-years (average 17.5, median 14.6). 24 were male, and 2 were female patients. High lipids peak at 1HMRS was observed in 16 of 16 examined tumors. On the other hand, in the PPT and meningioma, lipid peaks were small or absent in 10 of 10 examined tumors. In NGGCT group, high lipids peak at 1HMRS was also observed in 11 of 12 examined tumors, while they did not show high intensity on DWI, rather, they showed low to high mixed intensity. ADC was statistically lower in germinoma group than in NGGCT group (P=0.0002). Relative tumor blood flow (rTBF) was statistically lower in germinoma group than in NGGCT group (P=0.0087). CONCLUSION: Lower ADC value, low rTBF and high lipids peak at 1HMRS are characteristics of germinoma.