title: Perfusion magnetic resonance imaging predicts patient outcome as an adjunct to histopathology: a second reference standard in the surgical and nonsurgical treatment of low-grade gliomas.
abstract: OBJECTIVE
  To determine whether relative cerebral blood volume (rCBV) can predict patient outcome, specifically tumor progression, in low-grade gliomas (LGGs) and thus provide a second reference standard in the surgical and postsurgical management of LGGs.
  
  
  METHODS
  Thirty-five patients with histologically diagnosed LGGs (21 low-grade astrocytomas and 14 low-grade oligodendrogliomas and low-grade mixed oligoastrocytomas) were studied with dynamic susceptibility contrast-enhanced perfusion magnetic resonance imaging. Wilcoxon tests were used to compare patients in different response categories (complete response, stable, progressive, death) with respect to baseline rCBV. Log-rank tests were used to evaluate the association of rCBV with survival and time to progression. Kaplan-Meier time-to-progression curves were generated. Tumor volumes and CBV measurements were obtained at the initial examination and again at follow-up to determine the association of rCBV with tumor volume progression.
  
  
  RESULTS
  Wilcoxon tests showed patients manifesting an adverse event (either death or progression) had significantly higher rCBV (P = 0.003) than did patients without adverse events (complete response or stable disease). Log-rank tests showed that rCBV exhibited a significant negative association with disease-free survival (P = 0.0015), such that low rCBV values were associated with longer time to progression. Kaplan-Meier curves demonstrated that lesions with rCBV less than 1.75 (n = 16) had a median time to progression of 4620 +/- 433 days, and lesions with rCBV more than 1.75 (n = 19) had a median time to progression of 245 +/- 62 days (P < 0.005). Lesions with low baseline rCBV (< 1.75) demonstrated stable tumor volumes when followed up over time, and lesions with high baseline rCBV (> 1.75) demonstrated progressively increasing tumor volumes over time.
  
  
  CONCLUSIONS
  Dynamic susceptibility contrast-enhanced perfusion magnetic resonance imaging may be used to identify LGGs that are either high-grade gliomas, misdiagnosed because of sampling error at pathological examination or that have undergone angiogenesis in the progression toward malignant transformation. This suggests that rCBV measurements may be used as a second reference standard to determine the surgical management/risk-benefit equation and postsurgical adjuvant therapy for LGGs.
authors.affiliation: Department of Radiology, New York University Medical Center, New York, New York 10016, USA. lawm01@med.nyu.edu
authors.forename: Meng
authors.initials: M
authors.lastname: Law
authors.forename: Sarah
authors.initials: S
authors.lastname: Oh
authors.forename: Glyn
authors.initials: G
authors.lastname: Johnson
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: David
authors.initials: D
authors.lastname: Zagzag
authors.forename: John
authors.initials: J
authors.lastname: Golfinos
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D001810:Blood Volume; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D002560:Cerebrovascular Circulation; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000175:diagnosis / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D011237:Predictive Value of Tests; D012015:Reference Standards; D016019:Survival Analysis; D016896:Treatment Outcome