Quantitative evaluation of benign meningioma and hemangiopericytoma with peritumoral brain edema by 64-slice CT perfusion imaging

Background Hemangiopericytomas (HPCs) have a relentless tendency for local recurrence and metastases,differentiating between benign meningiomas and HPCs before surgery is important for both treatment planning and the prognosis appraisal.The purpose of this study was to evaluate the correlations between CT perfusion parameters and microvessel density (MVD) in extra-axial tumors and the possible role of CT perfusion imaging in preoperatively differentiating benign meningiomas and HPCs.Methods Seventeen patients with benign meningiomas and peritumoral edema, 12 patients with HPCs and peritumoral edema underwent 64-slice CT perfusion imaging pre-operation.Perfusion was calculated using the Patlak method.The quantitative parameters, include cerebral blood volume (CBV), permeability surface (PS) of parenchyma, peritumoral edema among benign meningiomas and HPCs were compared respectively.CBV and PS in parenchyma, peritumoral edema of benign meningiomas and HPCs were also compared to that of the contrallateral normal white matter respectively.The correlations between CBV, PS of tumoral parenchyma and MVD were examined.Results The value of CBV and PS in parenchyma of HPCs were significantly higher than that of benign meningiomas (P＜0.05), while the values of CBV and PS in peritumoral edema of benign meningiomas and HPCs were not significantly different (P ＞0.05).MVD in parenchyma of HPCs were significantly higher than that of benign meningiomas (P＜0.05).There were positive correlations between CBV and MVD (r=0.648, P＜0.05), PS and MVD (r=0.541, P＜0.05) respectively.Furthermore, the value of CBV and PS in parenchyma of benign meningiomas and HPCs were significantly higher than that of contrallateral normal white matter (P＜0.05), the value of CBV in peritumoral edema of benign meningiomas and HPCs were significantly lower than that of contrallateral normal white matter (P＜0.05), while the value of PS in peritumoral edema of benign meningiomas and HPCs were not significantly different with that of contrallateral normal white matter (P ＞0.05).Conclusions CT perfusion imaging can provide critical information on the vascuiarity of HPC and benign meningiomas.Determination of maximal CBV and corresponding PS values in the parenchyma may be useful in the preoperative differentiating HPC from benign meningiomas.