Diagnostic and Interventional Radiology
Neuroradiology - Original Article

The Reliability and inter-observer reproducibility of T2/FLAIR mismatch in the diagnosis of IDH-mutant astrocytomas

1.

Department of Radiology, Muğla Sıtkı Koçman University School of Medicine, Muğla, Turkey

2.

Department of Radiology, Acıbadem Mehmet Ali Aydınlar University School of Medicine, İstanbul, Turkey

3.

Department of Pathology, Acıbadem Mehmet Ali Aydınlar University School of Medicine, Acıbadem Altunizade Hospital, İstanbul, Turkey

4.

Department of Neurosurgery, Acıbadem Mehmet Ali Aydınlar University School of Medicine, İstanbul, Turkey

Diagn Interv Radiol 2020; 1: -
Read: 350 Published: 26 November 2020

PURPOSE: The reliability and reproducibility of T2/FLAIR mismatch were investigated in the diagnosis of IDH-mutant astrocytoma between WHO grade II and III diffuse hemispheric gliomas. 

 

METHODS: WHO grade II and grade III diffuse hemispheric gliomas (n=133) were included in the study at our own institute. Pathological findings and molecular markers of the cases were reviewed with the criteria of WHO 2016. The finding of mismatch between T2W and FLAIR images in preoperative MRI of the cases was evaluated by two different radiologists. The readers reviewed MRIs blinded of each other and the histopathologic diagnosis or molecular subset of tumors. The cases were classified as IDH-mutant astrocytoma, oligodendroglioma and IDH-wild type astrocytoma according to molecular and genetic features.
 

RESULTS: T2/FLAIR mismatch-positivity was observed in 46 (34.6%) of the patients. T2/FLAIR mismatch-positivity was observed 42/75 (56%) in IDH-mutant astrocytomas, 4/43 (9.30%) in oligodendrogliomas and 0/15 (0%) in IDH-wt astrocytomas. When we compare the T2/FLAIR mismatch ratio in IDH-mutant astrocytomas (WHO grade II and grade III) with the oligodendrogliomas, this difference was statistically significant (chi-square, p <0.05). The sensitivity, specificity, PPV, NPV and accuracy of T2/FLAIR mismatch in predicting IDH-mutant astrocytomas were 58.7%, 90.7%, 91.7%, 61.4% and 70.3% respectively. Radiologist no1 diagnosed T2/FLAIR mismatch in 48/133 (36.1%) of the cases and Radiologist no2 in 66/133 (49.6%) of the cases. The interrater agreement for the T2/FLAIR mismatch sign was 0.61 (p <0.05), 95% CI (0.55, 0.67).
 

CONCLUSION: T2/FLAIR mismatch appears to be an important MRI finding in distinguishing IDH-mutant astrocytomas from other diffuse hemispheric gliomas. However, it should be kept in mind that T2/FLAIR mismatch sign can be seen a minority of oligodendrogliomas besides IDH-mutant astrocytomas. 

 

EISSN 1305-3612