The Consistence of Dynamic Contrast-Enhanced MRI and Filter-Exchange Imaging in Measuring Water Exchange Across the Blood-Brain Barrier in High-Grade Glioma

Background: Water exchange across blood-brain barrier (BBB) (WEXBBB) is an emerging biomarker of BBB dysfunction with potential applications in many brain diseases. Several MRI methods have been proposed to measure WEXBBB, but evidence remains scarce whether different methods can produce comparable WEXBBB. Purpose: To explore whether dynamic contrast-enhanced (DCE)-MRI and vascular water exchange imaging (VEXI) could produce comparable WEXBBB in high-grade glioma (HGG) patients. Study Type: Prospective cross-sectional. Subjects: 13 HGG patients (58.4 +/- 9.4 years, 9 females, 4 WHO III and 9 WHO IV). Field Strength/Sequence: A 3 T, spoiled gradient-recalled-echo DCE-MRI and VEXI containing two pulsed-gradient spinecho blocks separated by a mixing block. Assessments: The enhanced tumor and contralateral normal-appearing white matter (cNAWM) volume-of-interests (VOIs) were drew by two neuroradiologists. And whole-brain NAWM and normal-appearing gray matter (NAGM) without tumoraffected regions were segmented by automated segmentation algorithm in FSL. Statistical Tests: Student's t-test was used to evaluate parameters difference between cNAWM and tumor, NAGM and NAWM, respectively. The correlation between vascular water efflux rate constant (k(bo)) from DCE-MRI and apparent exchange rate across BBB (AXRBBB) from VEXI was evaluated by Pearson correlation. P < 0.05 was considered statistically significant. Results: Compared with cNAWM, both kbo and AXRBBB were significantly reduced in tumor (kbo = 3.50 +/- 1.18 sec(-1) vs. 1.03 +/- 0.75 sec(-1); AXR(BBB) = 3.54 +/- 1.11 sec(-1) vs. 1.94 +/- 1.04 sec(-1)). Both kbo and AXR(BBB) showed significantly higher values in NAWM than NAGM (k(bo) = 3.50 +/- 0.59 sec(-1) vs. 2.10 +/- 0.56 sec(-1); AXR(BBB) = 3.35 +/- 0.77 sec(-1) vs. 2.07 +/- 0.52 sec(-1)). The VOI-averaged k(bo) and AXR(BBB) were also linearly correlated in tumor, NAWM, and NAGM (r = 0.59). Data Conclusion: DCE-MRI and VEXI showed comparable and correlated WEXBBB in HGG patients, suggesting that the consistence and reliability of these two MRI methods in measuring WEXBBB.