Arterial spin labeling of hemangioblastoma: Differentiation from metastatic brain tumors based on quantitative blood flow measurement

Introduction Hemangioblastoma and metastatic tumors are the major differential diagnoses for the posterior fossa tumors in adults. Our purpose was to evaluate the efficacy of ASL in differentiating hemangioblastomas from metastatic brain tumors. Methods A total of 19 patients including 5 with a hemangioblastomas and 14 with metastatic tumors (7 from lung cancer, 4 frombreast cancer, 1 fromRCC, 1 from gastric cancer, and 1 from unknown origin) were enrolled in this study. ASL was performed using a pulsed ASL method at a 3-T unit. aTBF was measured as a mean absolute blood flow value within a region of interest drawn in the tumor. In addition, rTBF was obtained by normalizing the aTBF by a blood flow measured in the normal-appearing cortical gray matter. The aTBF and rTBF values were compared between hemangioblastomas and metastatic tumors using Student's t test. Results Both the aTBF and rTBF values were significantly higher in hemangioblastomas (mean aTBF±SD=437± 274 mL/100 g/min, mean rTBF±SD=7.96±3.12) in comparison with metastatic brain tumors (mean aTBF±SD= 125±134 mL/100 g/min, mean rTBF±SD=2.98±3.91; P<0.05, respectively). However, a metastasis from RCC showed very high aTBF (559 mL/100 g/min) and rTBF (16.2). Conclusion Our results demonstrated that ASL provides useful information to differentiate between hemangioblastomas and metastatic brain tumors. Metastasis from RCC may mimic hemangioblastoma on ASL blood flow measurement.