Discriminating pyogenic brain abscesses, necrotic glioblastomas, and necrotic metastatic brain tumors by means of susceptibility-weighted imaging

Eur Radiol. 2015 May;25(5):1413-20. doi: 10.1007/s00330-014-3518-x. Epub 2014 Dec 3.


Objectives: To investigate the feasibility of using susceptibility-weighted imaging (SWI) to discriminate abscesses and necrotic tumours.

Methods: Twenty-one patients with pyogenic abscesses, 21 patients with rim-enhancing glioblastomas and 23 patients with rim-enhancing metastases underwent SWI. Intralesional susceptibility signal (ILSS) was analyzed employing both qualitative (QL) and semi-quantitative (SQ) methods. Logistic regression models and receiver operating characteristic analysis were used to demonstrate the discriminating power.

Results: In QL analysis, ILSSs were seen in 12 of 21 abscesses, in 20 of 21 glioblastomas, and in 16 of 23 metastases. In SQ analysis, a low degree of ILSS (85.8 %) was in the majority of abscesses and a high degree of ILSS (76.2 %) was in the majority of glioblastomas. SQ model was significantly better than QL model in distinguishing abscesses from glioblastomas (P < .001). A derived ILSS cutoff grade of 1 or less was quantified as having a sensitivity of 85.7 %, specificity of 90.5 %, accuracy of 88.1 %, PPV of 90.0 %, and NPV of 86.4 % in distinguishing abscesses from glioblastomas.

Conclusions: A high-grade ILSS may help distinguish glioblastomas from abscesses and necrotic metastatic brain tumours. The lack of ILSS or low-grade ILSS can be a more specific sign in the imaging diagnosis of abscesses.

Key points: • ILSS of SWI can contribute to differential diagnosis of rim-enhanced mass. • Low-grade ILSS can be a more specific sign in abscesses. • High-grade ILSS may help distinguish necrotic glioblastomas from abscesses. • ILSS spreads across the four ILSS categories in metastases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain / pathology*
  • Brain Abscess / diagnosis*
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / pathology
  • Diagnosis, Differential
  • Diagnostic Imaging
  • Feasibility Studies
  • Female
  • Glioblastoma / diagnosis*
  • Glioblastoma / pathology
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Middle Aged
  • Necrosis / diagnosis
  • Necrosis / pathology
  • Observer Variation
  • ROC Curve
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity