Parametric response maps of perfusion MRI may identify recurrent glioblastomas responsive to bevacizumab and irinotecan

PLoS One. 2014 Mar 27;9(3):e90535. doi: 10.1371/journal.pone.0090535. eCollection 2014.


Background: Perfusion weighted imaging (PWI) can be used to measure key aspects of tumor vascularity in vivo and recent studies suggest that perfusion imaging may be useful in the early assessment of response to angiogenesis inhibitors. Aim of this work is to compare Parametric Response Maps (PRMs) with the Region Of Interest (ROI) approach in the analysis of tumor changes induced by bevacizumab and irinotecan in recurrent glioblastomas (rGBM), and to evaluate if changes in tumor blood volume measured by perfusion MRI may predict clinical outcome.

Methods: 42 rGBM patients with KPS ≥ 50 were treated until progression, as defined by MRI with RANO criteria. Relative cerebral blood volume (rCBV) variation after 8 weeks of treatment was calculated through semi-automatic ROI placement in the same anatomic region as in baseline. Alternatively, rCBV variations with respect to baseline were calculated into the evolving tumor region using a voxel-by-voxel difference. PRMs were created showing where rCBV significantly increased, decreased or remained unchanged.

Results: An increased blood volume in PRM (PRMCBV+) higher than 18% (first quartile) after 8 weeks of treatment was associated with increased progression free survival (PFS; 24 versus 13 weeks, p = 0.045) and overall survival (OS; 38 versus 25 weeks, p = 0.016). After 8 weeks of treatment ROI analysis showed that mean rCBV remained elevated in non responsive patients (4.8 ± 0.9 versus 5.1 ± 1.2, p = 0.38), whereas decreased in responsive patients (4.2 ± 1.3 versus 3.8 ± 1.6 p = 0.04), and re-increased progressively when patients approached tumor progression.

Conclusions: Our data suggest that PRMs can provide an early marker of response to antiangiogenic treatment and warrant further confirmation in a larger cohort of GBM patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Bevacizumab / administration & dosage
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / drug therapy*
  • Brain Neoplasms / mortality
  • Camptothecin / administration & dosage
  • Camptothecin / analogs & derivatives
  • Combined Modality Therapy
  • Female
  • Follow-Up Studies
  • Glioblastoma / diagnosis*
  • Glioblastoma / drug therapy*
  • Glioblastoma / mortality
  • Humans
  • Irinotecan
  • Magnetic Resonance Imaging* / methods
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local
  • Perfusion Imaging* / methods
  • Survival Analysis
  • Treatment Outcome
  • Young Adult


  • Bevacizumab
  • Irinotecan
  • Camptothecin

Grant support

This work was partially supported by a grant from the Italian Ministry of Health [RF-INN-2008-1142520 to GF]. Drugs were supplied by Roche S.p.A. (Monza, Italy) and Hospira (Napoli, Italy). This work was partially funded by MIUR, FIRB project “Materiali fluorurati nanostrutturati come mezzi di contrasto intelligenti in 19F-RMN (FLUORIMAGING)” project no. RBAP1183B5. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding received for this study.