Analysis of fractional anisotropy facilitates differentiation of glioblastoma and brain metastases in a clinical setting

Eur J Radiol. 2016 Dec;85(12):2182-2187. doi: 10.1016/j.ejrad.2016.10.002. Epub 2016 Oct 4.


Purpose: Differentiating glioblastoma from brain metastases is important for therapy planning. Diffusion tensor imaging (DTI) was described as a promising tool, however with conflicting results.

Aim: of this study was to analyze the clinical utility of DTI for the differentiation of brain metastases and glioblastoma.

Methods: 294 patients (165 glioblastoma, 129 brain metastases) with preoperative DTI were included in this retrospective study. Fractional anisotropy (FA) was measured via regions of interest (ROIs) in the contrast-enhancing tumor, the necrosis and the FLAIR-hyperintense non-enhancing peritumoral region (NEPTR). Two neuroradiologists classified patient cases as glioblastoma or brain metastases without and with knowledge of FA values.

Results: Glioblastoma showed significantly higher FAcontrast (median glioblastoma=0.33, metastases=0.23; P<0.001) whereas no significant difference was observed for FANEPTR (0.21 vs. 0.22; P=0.28) and for FAnecrosis (0.17 vs. 0.18, P=0.37). FA improved diagnostic accuracy of the neuroradiologists significantly from an AUC of 0.84/0.85 (Reader1/Reader2) to 0.89/0.92.

Conclusions: Glioblastoma show significantly higher FA values in the contrast enhancing tumor part than brain metastases. Implementation of a ROI-based measurement of FA values and FA color maps in clinical routine helps to differentiate between glioblastoma and brain metastases.

Keywords: Brain metastases; Diffusion tensor imaging; Fractional anisotropy; Glioblastoma.

MeSH terms

  • Anisotropy
  • Brain / pathology
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / secondary
  • Cohort Studies
  • Contrast Media
  • Diagnosis, Differential
  • Diffusion Magnetic Resonance Imaging / methods
  • Diffusion Tensor Imaging / methods*
  • Glioblastoma / diagnosis*
  • Humans
  • Image Enhancement / methods
  • Necrosis
  • Neoplasm Recurrence, Local / diagnosis
  • Retrospective Studies


  • Contrast Media