Association of ADC of hyperintense lesions on FLAIR images with TERT promoter mutation status in glioblastoma IDH wild type

Background: Although mutations in telomerase reverse transcriptase ( TERT ) promoter ( TERT p) are the most common alterations in glioblastoma (GBM), predicting TERT p mutation status by preoperative imaging is difficult. We determined whether tumour-surrounding hyperintense lesions on fluid-attenuated inversion recovery (FLAIR) were superior to those of contrast-enhanced lesions (CELs) in assessing TERT p mutation status using magnetic resonance imaging (MRI). Methods: This retrospective study included 114 consecutive patients with primary isocitrate dehydrogenase (IDH)-wild-type GBM. The apparent diffusion coefficient (ADC) and volume of CELs and FLAIR hyperintense lesions (FHLs) were determined, and the correlation between MRI features and TERT p mutation status was analyzed. In a subset of cases, FHLs were histopathologically analyzed to determine the correlation between tumor cell density and ADC. Results: TERT p mutations were present in 77 (67.5%) patients. The minimum ADC of FHLs was significantly lower in the TERT p-mutant group than in the TERT p-wild-type group (mean, 958.9 × 10 −3 and 1092.1 × 10 −3 mm 2 /s, respectively, P < 0.01). However, other MRI features, such as CEL and FHL volumes, minimum ADC of CELs, and FHL/CEL ratio, were not significantly different between the two groups. Histopathologic analysis indicated high tumor cell density in FHLs with low ADC. Conclusion: The ADC of FHLs was significantly lower in IDH-wild-type GBM with TERT p mutations, suggesting that determining the ADC of FHLs on preoperative MRI might be helpful in predicting TERT p mutation status and surgical planning.