title: Microvascular permeability of brain astrocytoma with contrast-enhanced magnetic resonance imaging: correlation analysis with histopathologic grade.
abstract: BACKGROUND
  The degree of pathological microvascular proliferation is an important element in evaluation of the astrocytoma grade. This study was aimed to quantitatively assess the microvascular permeability of brain astrocytoma with the volume transfer constant (K(trans)) and volume of extravascular extracellular space per unit volume of tissue (Ve) from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and to evaluate the effectiveness of the K(trans) and Ve in the grading of astrocytoma.
  
  
  METHODS
  The highest values of the K(trans) and Ve of 67 patients with astrocytoma (27 with grade II, 12 with grade III, and 28 with grade IV) were obtained. The comparisons of the differences of the K(trans) and Ve between the different grades were conducted using the Mann-Whitney rank-sum tests. Spearman's rank correlation coefficients were determined between K(trans) values, Ve values and astrocytoma grades. Receiver operating characteristic (ROC) curve analyses were performed to determine the cut-off values for the K(trans) and Ve to distinguish between the different grades of astrocytoma.
  
  
  RESULTS
  There were significant differences (P < 0.001) between the different grades in the K(trans) values and Ve values, except for grades III and IV. The K(trans) values and Ve values were both correlated with astrocytoma grades (both P < 0.001). The ROC curve analyses showed that the cut-off values for the K(trans) and Ve provided the best combination of sensitivity and specificity in distinguishing between grade II and grade III or IV astrocytomas.
  
  
  CONCLUSIONS
  DCE-MRI can play an important role in assessing the microvascular permeability and the grading of brain astrocytoma.
authors.affiliation: Department of Radiology, Affiliated Hospital of Nantong University, Nantong 226001, China.
authors.forename: Zhong-Zheng
authors.initials: ZZ
authors.lastname: Jia
authors.forename: Dao-Ying
authors.initials: DY
authors.lastname: Geng
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Xing-Rong
authors.initials: XR
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000473:pathology* / Q000503:physiopathology*; D001932:Brain Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D002199:Capillary Permeability / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D055815:Young Adult