title: Permeability estimates in histopathology-proved treatment-induced necrosis using perfusion CT: can these add to other perfusion parameters in differentiating from recurrent/progressive tumors?
abstract: OBJECTIVE
  Differentiating treatment effects from RPT is a common yet challenging task in a busy neuro-oncologic practice. PS probably represents a different aspect of angiogenesis and vasculature and can provide additional physiologic information about recurrent/progressive enhancing lesions. The purpose of the study was to use PS measured by using PCT to differentiate TIN from RPT in patients with previously irradiated brain tumor who presented with a recurrent/progressive enhancing lesion.
  
  
  METHODS
  Seventy-two patients underwent PCT for assessment of a recurrent/progressive enhancing lesion from January 2006 to November 2009. Thirty-eight patients who underwent surgery and histopathologic diagnosis were included in this analysis. Perfusion parameters such as PS, CBV, CBF, and MTT were obtained from the enhancing lesion as well as from the NAWM.
  
  
  RESULTS
  Of 38 patients, 11 were diagnosed with pure TIN and 27 had RPT. Patients with TIN showed significantly lower mean PS values than those with RPT (1.8 ± 0.8 versus 3.6 ± 1.6 mL/100 g/min; P value=.001). The TIN group also showed lower rCBV (1.2 ± 0.3 versus 2.1 ± 0.7; P value<.001), lower rCBF (1.2 ± 0.5 versus 2.6 ± 1.7; P value=.004), and higher rMTT (1.4 ± 0.4 versus 1.0 ± 0.4; P value=.018) compared with the RPT group.
  
  
  CONCLUSIONS
  PCT and particularly PS can be used in patients with previously treated brain tumors to differentiate TIN from RPT. PS estimates can help increase the accuracy of PCT in differentiating these 2 entities.
authors.affiliation: Division of Neuroradiology, Department of Radiology, Henry Ford Health System, 2799 West Grand Blvd, Detroit, MI 48202, USA. rajanj@rad.hfh.edu
authors.forename: R
authors.initials: R
authors.lastname: Jain
authors.forename: J
authors.initials: J
authors.lastname: Narang
authors.forename: L
authors.initials: L
authors.lastname: Schultz
authors.forename: L
authors.initials: L
authors.lastname: Scarpace
authors.forename: S
authors.initials: S
authors.lastname: Saksena
authors.forename: S
authors.initials: S
authors.lastname: Brown
authors.forename: J P
authors.initials: JP
authors.lastname: Rock
authors.forename: M
authors.initials: M
authors.lastname: Rosenblum
authors.forename: J
authors.initials: J
authors.lastname: Gutierrez
authors.forename: T
authors.initials: T
authors.lastname: Mikkelsen
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D011878:Radiotherapy / Q000009:adverse effects; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult