Mapping high-grade glioma response to chemoradiotherapy: Insights from fractional anisotropy and mean diffusivity

The current study aimed to investigate the use of fractional anisotropy (FA) and mean diffusivity (MD) as a noninvasive probe for assessing chemoradiotherapy (CRT) efficacy in 32 high-grade glioma patients (HGGs). Diffusion tensor imaging (DTI) was performed pre- and post-CRT, and FA and MD maps were constructed with Philips MRI 1.5 T beside Intellispace software. Tumor regression and progression were assessed by changes in tumor size monitored with T1-contrast enhancement, with 15 cases (46.9%) demonstrating regression and 17 cases (53.1%) showing progression. The cut-off values of mean pre- CRT FA and MD in the tumor core were 0.345 and 0.957 x 10-3 mm2/s, respectively, with a sensitivity of 73.3% and 86.7% and a specificity of 70.6% and 52.9%. In the peritumoral zone, the mean values of pre-FA and MD were 0.415 and 1.21 x 10-3 mm2/s, respectively, with a sensitivity of 93.3% and 86.7% and a specificity of 76.5% for both. Comparatively, the cutoff values of mean after CRT FA and MD in the tumor core were 0.295 and 0.965 x 10-3 mm2/s, respectively, with a sensitivity of 99.2% and 98.1% and a specificity of 94.1% and 93.1%. Higher post-CRT FA and MD values were associated with better treatment response rates, indicating that FA and MD are valuable DTI metrics for assessing CRT efficacy in HGG regression and progression without invasive procedures.