Radiographic assessment of contrast enhancement and T2/FLAIR mismatch sign in lower grade gliomas: correlation with molecular groups

J Neurooncol. 2019 Jan;141(2):327-335. doi: 10.1007/s11060-018-03034-6. Epub 2018 Dec 7.


Purpose: With the updated World Health Organization (WHO) 2016 neuropathological diagnostic criteria, radiographic prognostic associations in lower-grade gliomas (LGG, WHO grade II and III) are undergoing re-evaluation.

Methods: We identified 316 LGG patients (151 grade II and 165 grade III) for a combined cohort from three independent databases. We analyzed the preoperative axial FLAIR, axial T2-weighted and post-gadolinium volumetric T1-weighted MR images. The molecular data collected included the status of IDH1/2, TP53, TERT promoter and ATRX mutations, in addition to 1p/19q co-deletions. In a subset of cases (n = 133), we assessed the "T2-FLAIR mismatch" sign.

Results: Gliomas were assigned to one of the three molecular groups: Group O (IDH-mutant, 1p/19q co-deleted oligodendrogliomas, n = 95), Group A (IDH-mutant, ATRX inactivated astrocytomas, n = 175) and Group G (IDH wild-type, GBM-like, n = 46). A contrast-enhancing tumor was seen in 98 patients (31%), most frequently in Group G (n = 28/45, 57%), when compared to Group A (n = 49/175, 28%) and Group O (n = 24/95, 25.3%) tumors (p = 0.008 and p = 0.0011, respectively). Consistent with previous reports, T2-FLAIR mismatch was preferentially found in Group A tumors (73.1%, 60 of 82), although its presence was not associated with survival, after controlling for molecular group. False positive mismatch sign was noted in 28.5% (12/42) Group O tumors, but none of the tumors in Group G. A combination of all three factors: age under 40 years at first diagnosis, a tumor size larger than 6 cm and T2-FLAIR mismatch was highly specific for IDH mutant astrocytoma (Group A).

Conclusion: We identify radiographic correlates of molecular groups in lower-grade gliomas, which join clinical demographic features in defining the characteristic presentation of these tumors. Radiographic correlates of prognosis in LGG require re-evaluation within molecular group.

Keywords: Contrast enhancement; Glioma; IDH mutation; Radiographic correlates; T2-FLAIR mismatch.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Brain Neoplasms / diagnostic imaging*
  • Brain Neoplasms / genetics
  • Brain Neoplasms / pathology*
  • Glioma / diagnostic imaging*
  • Glioma / genetics
  • Glioma / pathology*
  • Humans
  • Isocitrate Dehydrogenase / genetics
  • Kaplan-Meier Estimate
  • Magnetic Resonance Imaging / methods*
  • Middle Aged
  • Mutation
  • Neoplasm Grading
  • Progression-Free Survival
  • Radiographic Image Enhancement*
  • Retrospective Studies
  • Sensitivity and Specificity
  • Tumor Suppressor Protein p53 / genetics
  • X-linked Nuclear Protein / genetics
  • Young Adult


  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Isocitrate Dehydrogenase
  • isocitrate dehydrogenase 2, human
  • IDH1 protein, human
  • ATRX protein, human
  • X-linked Nuclear Protein