NI-17 T2-FLAIR MISMATCH SIGN IN DIFFUSE GLIOMA AND DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOR

T2-FLAIR mismatch sign was reported as a specific imaging marker for diffuse astrocytoma with IDH-mutant and 1p/19q non-codeletion. However, most of the previous studies for T2-FLAIR mismatch were confirmed only among low grade glioma. The purpose of this study is to assess the T2-FLAIR mismatch sign in supratentorial diffuse glioma, diffuse midline glioma and dysembryoplastic neuroepithelial tumor (DNT) to unveil the exception rules of the sign.

In total, 51 patients were included in this study; 33 supratentorial diffuse glioma (18 diffuse astrocytoma with IDH mutant (IDHmut-Noncodel), 12 oligodendroglioma with IDH-mutant and 1p19q codeletion (IDHmut-Codel), 3 diffuse astrocytoma with IDH wildtype (IDHwt)), 18 diffuse midline glioma and 11 DNT. The tumors were evaluated by 2 independent reviewers to assess presence or absence of T2-FLAIR mismatch sign.

Ten out of 18 cases of IDHmut-Noncodel presented T2-FLAIR mismatch sign. None of the other supratentorial diffuse glioma (IDHmut-Codel and IDHwt) presented T2-FLAIR mismatch. The T2-FLAIR mismatch sign for IDHmut-Noncodel presented 100% positive predictive values among supratentorial diffuse glioma. However, 8 out of 18 cases of diffuse midline glioma and 8 out of 11 cases of DNT also presented the T2-FLAIR mismatch.

The T2-FLAIR mismatch sign was specific marker for IDHmut-NonCodel among supratentorial diffuse glioma. Physicians need to be aware that diffuse midline glioma and DNT could present the T2-FLAIR mismatch sign.