Comparison of the effectiveness of MRI perfusion and fluorine-18 FDG PET-CT for differentiating radiation injury from viable brain tumor: a preliminary retrospective analysis with pathologic correlation in all patients

Clin Imaging. May-Jun 2013;37(3):451-7. doi: 10.1016/j.clinimag.2012.08.008. Epub 2012 Oct 12.


Objectives: Differentiating radiation injury from viable tumor is important for optimizing patient care. Our aim was to directly compare the effectiveness of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and dynamic susceptibility-weighted contrast-enhanced (DSC) magnetic resonance (MR) perfusion in differentiating radiation effects from tumor growth in patients with increased enhancement following radiotherapy for primary or secondary brain tumors.

Materials and methods: We retrospectively identified 12 consecutive patients with primary and secondary brain tumors over a 1-year period that demonstrated indeterminate enhancing lesions after radiotherapy and that had undergone DSC MR perfusion, FDG PET-CT, and subsequent histopathologic diagnosis. The maximum standardized uptake value (SUV) of the lesion (SUVlesion max), SUVratio (SUVlesion max/SUVnormal brain), maximum relative cerebral blood volume, percentage of signal intensity recovery, and relative peak height were calculated from the positron emission tomography and MR perfusion studies. A prediction of tumor or radiation injury was made based on these variables while being blinded to the results of the surgical pathology.

Results: SUVratio had the highest predictive value (area under the curve=0.943) for tumor progression, although this was not statistically better than any MR perfusion metric (area under the curve=0.757-0.829).

Conclusions: This preliminary study suggests that FDG PET-CT and DSC MR perfusion may demonstrate similar effectiveness for distinguishing tumor growth from radiation injury. Assessment of the SUVratio may increase the sensitivity and specificity of FDG PET-CT for differentiating tumor and radiation injury. Further analysis is needed to help define which modality has greater predictive capabilities.

Publication types

  • Comparative Study

MeSH terms

  • Brain Injuries / diagnosis*
  • Brain Injuries / etiology
  • Brain Neoplasms / complications
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / radiotherapy*
  • Diagnosis, Differential
  • Female
  • Fluorodeoxyglucose F18*
  • Humans
  • Magnetic Resonance Angiography / methods*
  • Male
  • Middle Aged
  • Multimodal Imaging / methods*
  • Neoplasm, Residual
  • Pilot Projects
  • Positron-Emission Tomography*
  • Radiation Injuries / diagnosis*
  • Radiation Injuries / etiology
  • Radiopharmaceuticals
  • Radiotherapy / adverse effects
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed*
  • Treatment Outcome


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18