title: Early perfusion changes in patients with recurrent high-grade brain tumor treated with Bevacizumab: preliminary results by a quantitative evaluation.
abstract: BACKGROUND
  To determine whether early monitoring of the effects of bevacizumab in patients with recurrent high-grade gliomas, by a Perfusion Computed Tomography (PCT), may be a predictor of the response to treatment assessed through conventional MRI follow-up.
  
  
  METHODS
  Sixteen patients were enrolled in the present study. For each patient, two PCT examinations, before and after the first dose of bevacizumab, were acquired. Areas of abnormal Cerebral Blood Volume (CBV) were manually defined on the CBV maps, using co-registered T1- weighted images, acquired before treatment, as a guide to the tumor location. Different perfusion metrics were derived from the histogram analysis of the normalized CBV (nCBV) maps; both hyper and hypo-perfused sub-volumes were quantified in the lesion, including tumor necrosis. A two-tailed Wilcoxon test was used to establish the significance of changes in the different perfusion metrics, observed at baseline and during treatment. The relationships between changes in perfusion and morphological MRI modifications at first follow-up were investigated.
  
  
  RESULTS
  Significant reductions in mean and median nCBV were detected throughout the entire patient population, after only a single dose of bevacizumab. The nCBV histogram modifications indicated the normalization effect of bevacizumab on the tumor abnormal vasculature. An improvement in hypoxia after a single dose of bevacizumab was predictive of a greater reduction in T1-weighted contrast-enhanced volumes at first follow-up.
  
  
  CONCLUSIONS
  These preliminary results show that a quantification of changes in necrotic intra-tumoral regions could be proposed as a potential imaging biomarker of tumor response to anti-VEGF therapies.
authors.affiliation: Radiology and Diagnostic Imaging Department, Regina Elena Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy. vidiri@ifo.it
authors.forename: Antonello
authors.initials: A
authors.lastname: Vidiri
authors.forename: Andrea
authors.initials: A
authors.lastname: Pace
authors.forename: Alessandra
authors.initials: A
authors.lastname: Fabi
authors.forename: Marta
authors.initials: M
authors.lastname: Maschio
authors.forename: Gaetano Marco
authors.initials: GM
authors.lastname: Latagliata
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Anelli
authors.forename: Francesca
authors.initials: F
authors.lastname: Piludu
authors.forename: Carmine Maria
authors.initials: CM
authors.lastname: Carapella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giovinazzo
authors.forename: Simona
authors.initials: S
authors.lastname: Marzi
mesh_terms: D000328:Adult; D000368:Aged; D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage*; D000068258:Bevacizumab; D001932:Brain Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D005260:Female; D005909:Glioblastoma / Q000098:blood supply / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000473:pathology; D005910:Glioma / Q000098:blood supply / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000098:blood supply / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D010477:Perfusion; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D020533:Angiogenesis Inhibitors; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab