Distinct Hemodynamic and Morphological Characteristics of Arteries Adjacent to White Matter Hyperintensities

Altered cerebral perfusion has been implicated in the development of white matter hyperintensities (WMHs), yet the specific influence of hemodynamic features in proximal arteries on WMH burden remains uncertain. This study aimed to investigate the relationship between arterial flow characteristics and WMH severity.

A total of 2631 subjects (68.6 ± 11.1 years, 50.3% female) who underwent MRI (magnetic resonance imaging) and MRA (magnetic resonance angiography) scans were involved in this retrospective observational study. Using an individualized simplified hemodynamic model, we derived arterial flow rate, mean pressure, and pressure drop for each MRA-visible branch. WMHs were quantified on T2-FLAIR images and categorized into periventricular and deep subtypes. The associations between arterial features and WMH burden were examined using general linear models.

Higher mean flow rate (β = 0.10, 95% CI: 0.06-0.14, p < 0.001) and mean pressure (β = 0.03, 95% CI: 0.02-0.04, p < 0.001) were associated with increased WMH volume. Adjacent-to-lesion terminal arterial branches (ALTAB), which represented arteries surrounding WMH, exhibited greater length (21.7 ± 8.21 mm vs. 13.3 ± 2.35 mm, p < 0.001), greater tortuosity (1.52 ± 0.39 vs. 1.26 ± 0.11, p < 0.001), lower mean flow rates (0.40 ± 0.09 mL/min vs. 0.90 ± 0.25 mL/min, p < 0.001) and lower pressure drops (0.42 ± 0.16 mmHg vs. 0.54 ± 0.15 mmHg, p < 0.001) compared to distant arteries. Greater WMH volume was found to be associated with an increased number of ALTAB.

The hemodynamic features of arteries surrounding WMH exhibited significant differences compared to those located further away. Such changes in arterial morphology and corresponding hemodynamic features might be associated with the severity of WMH.