title: Comparison of CT perfusion parameters and microvessel density in intracranial hemangiopericytomas with peritumoral edema.
abstract: OBJECTIVE
  Intracranial hemangiopericytomas (HPCs) are rare, and they have a tendency for local recurrence and metastases. The purpose of this study was to evaluate the relationship between CT perfusion (CTP) parameters and microvessel density (MVD) of HPCs and compare CTP parameters in parenchyma and peritumoral edema of HPCs.
  
  
  METHODS
  The study was approved by the ethics committee, and written informed consent was obtained. Ten patients with HPCs and peritumoral edema, confirmed by pathological results, received 64-slice CT perfusion imaging before operation. To evaluate vascular attenuation of tumoral parenchyma, we immunostained the specimen sections for CD-34, measured the integrated optical density of all the positive stained CD-34 cells in the microscopic field, and calculated its ratio to total area of field as MVD. Perfusion analysis was calculated using the Patlak method. Using a 1-cm distance from the outer enhancing tumor margin as a boundary, the peritumoral edema was divided into an immediate and a distant part. The quantitative CTP parameters, including cerebral blood volume (CBV), permeability-surface area product (PS) of parenchyma, and immediate and distant peritumoral edemas, were compared. CBV and PS in parenchyma and immediate and distant peritumoral edemas of HPCs were also compared to their respective contralateral normal white matter. The correlations between MVD, CBV, and PS of tumoral parenchyma were analyzed.
  
  
  RESULTS
  Positive correlations existed between CBV and MVD, PS and MVD (P < 0.05) respectively in the 10 patients. Furthermore, the values of CBV and PS in parenchyma of HPCs were significantly higher than those of the contralateral normal white matter and peritumoral edema (P < 0.05). The value of CBV in peritumoral edema of HPCs were lower than that of contralateral normal white matter (P < 0.05), while the value of PS in immediate and distant peritumoral edemas of HPCs were not significantly difference with that of contralateral normal white matter (P > 0.05). Finally, the values of CBV and PS did not show a significant difference between immediate and distant peritumoral edemas.
  
  
  CONCLUSIONS
  CT perfusion imaging, especially determination of maximal CBV and corresponding PS values in the parenchyma, may be a useful and non-invasive technique for the preoperative evaluation of hemodynamic features of HPCs with peritumoral edema. CBV of peritumoral edema indicate that HPCs have a possibility of infiltration, this need further radiological-pathological research.
authors.affiliation: Department of Radiology,Huashan hospital, Fudan University, Wulumuqizhong Road, Shanghai, China. shuang6895@yahoo.com.cn
authors.forename: Chen
authors.initials: C
authors.lastname: Shuang
authors.forename: Ren
authors.initials: R
authors.lastname: Guang
authors.forename: Feng
authors.initials: F
authors.lastname: Xiaoyuan
authors.forename: Geng
authors.initials: G
authors.lastname: Daoying
authors.forename: Wang
authors.initials: W
authors.lastname: Yin
mesh_terms: D000328:Adult; D000368:Aged; D001929:Brain Edema / Q000000981:diagnostic imaging*; D001932:Brain Neoplasms / Q000098:blood supply*; D005260:Female; D006393:Hemangiopericytoma / Q000098:blood supply* / Q000000981:diagnostic imaging; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D055806:Microvessels / Q000000981:diagnostic imaging*; D008875:Middle Aged; D035583:Rare Diseases / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods