Assessment of tumor blood flow and its correlation with histopathologic features in skull base meningiomas and schwannomas by using pseudo-continuous arterial spin labeling images.

OBJECTIVE: We aimed to investigate whether pseudo-continuous arterial spin labeling (pcASL)-MRI can adequately evaluate tumor perfusion even if the tumors are located in the skull base region and evaluate the correlation between tumor blood flow (TBF) and the histopathologic features of skull base meningiomas and schwannomas. MATERIALS AND METHODS: We enrolled 31 patients with skull base meningioma (n=14) and schwannoma (n=17) who underwent surgical resection. TBF was calculated from pcASL. Tissue sections were stained with CD34 to evaluate microvessel area (MVA). TBF and MVA ratio were compared between meningiomas and schwannomas using Mann-Whitney U-test. The correlations between MVA ratio and TBF were evaluated in each tumor by using single linear regression analysis and Spearman's rank correlation coefficients (rs). RESULTS: MVA ratio and TBF were significantly higher in meningioma than in schwannoma (both p<0.01). Correlation analyses revealed significant positive correlations between MVA ratio and both mean and max TBF for meningiomas (rs=0.89, 0.81, both p<0.01). There was a weak positive correlation between MVA ratio and mean TBF for schwannomas (rs=0.43, p=0.04). However, no significant correlation was found between MVA ratio and max TBF for schwannoma. CONCLUSIONS: pcASL-MRI is useful for evaluating tumor perfusion even if the tumors are located in the skull base region. Moreover, pcASL-TBF was significantly higher in most meningiomas compared to schwannomas, which can help in the differential diagnosis of the 2 tumor types even without the use of contrast material.