Correlation between contrast-enhanced T2 fluid-attenuated inversion recovery enhancement and dynamic contrast-enhanced magnetic resonance imaging permeability in brain metastases

Background: Contrast-enhanced T2 fluid-attenuated inversion recovery (CE-T2 FLAIR) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) provide complementary information on lesion enhancement and vascular permeability. This study aimed to assess the correlation between CE-T2 FLAIR enhancement and DCE-MRI-derived permeability parameters in brain metastases. Methods: This single-center retrospective study included 43 patients with 80 brain metastases confirmed by pathology or follow-up between January 2018 and July 2024. All patients underwent T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), T2 FLAIR, DCE-MRI, CE-T2 FLAIR, and contrast-enhanced T1WI (CE-T1WI) examinations. Quantitative DCE-MRI parameters were evaluated for all lesions, including the volume transfer constant (Ktrans) and the reverse volume transfer constant (Kep). CE-T2 FLAIR enhancement was assessed using contrast ratio (CR) and percentage increase (PI). Lesions were grouped by enhancement level on CE-T2 FLAIR relative to CE-T1WI: hyperenhancement (Group A), similar enhancement (Group B), and hypoenhancement (Group C). Group differences were assessed using the Kruskal-Wallis test, followed by Bonferroni-adjusted Mann-Whitney U tests for pairwise comparisons; associations between CR/PI and Ktrans/Kep were examined using Spearman’s rank correlation. Results: Groups A, B, and C included 17, 45, and 18 lesions, respectively. Group A showed significantly higher CR and PI and lower Ktrans and Kep compared with Groups B and C (all P