Clinicopathological and radiological characteristics of false-positive and false-negative results in T2-FLAIR mismatch sign of IDH-mutated gliomas.

Purpose: To explore the clinicopathological and radiological characteristics associated with false-positive and false-negative results in the identification of isocitrate dehydrogenase (IDH) mutations in gliomas using the T2-fluid-attenuated inversion recovery (FLAIR) mismatch sign.

Methods: In 1515 patients with cerebral gliomas, tumor location, restricted diffusion using diffusion-weighted imaging, and the T2-FLAIR mismatch sign were retrospectively analyzed using preoperative magnetic resonance imaging. Moreover, both the false-positive and false-negative results of the T2-FLAIR mismatch sign were obtained. Univariate and multivariate logistic analyses were performed to evaluate the risk factors associated with false-positive and false-negative results.

Results: The overall false-positive rate was 3.5 % (53/1515), and its independent risk factors were the patient's age (adjusted odds ratio [OR], 0.977; 95 % confidence interval [CI], 0.957, 0.997; P = 0.027) and non-restricted diffusion (adjusted OR, 1.968; 95 % CI, 1.060, 3.652; P = 0.032). The overall false-negative rate was 39.7 % (602/1515); its independent risk factors were the patient's age (adjusted OR, 1.022; 95 % CI, 1.005, 1.038; P = 0.008), 1p/19q co-deletion (adjusted OR, 3.334; 95 % CI, 1.913, 5.810; P < 0.001), and telomerase reverse transcriptase promoter mutation (adjusted OR, 2.004; 95 % CI, 1.181, 3.402; P = 0.010). For the mismatch sign in idiopathic IDH, the area under the receiver operating characteristic curve (AUC) was 0.602. The combined AUC for the T2-FLAIR mismatch sign and risk factors was 0.871.

Conclusions: Clinicopathological and radiological characteristics can lead to the misinterpretation of IDH status in gliomas based on the T2-FLAIR mismatch sign. However, this can be avoided if careful attention is paid.