Decreased Cerebral Blood Flow and Delayed Arterial Transit Are Independently Associated With White Matter Hyperintensity

Abstract

Aim: White matter hyperintensities (WMH) and lacunes were important features of cerebral small vessel disease (CSVD), which contributes to 25% of ischemic strokes and 45% of dementias. Currently, the underlying mechanisms of WMH and lacunes are not clear, and the role of hemodynamic changes is not fully investigated. In this study, we aimed to measure the cerebral blood flow (CBF) and arterial transit in CSVD patients and to investigate their association with WMH and lacunes.

Methods: We retrospectively analyzed the prospectively collected database of CSVD patients. Ninety-two CSVD patients with complete imaging data were included. We used arterial spin labeling (ASL) with post-labeling delay time (PLD) of 1,525 ms and 2,025 ms to measure CBF respectively, and the difference between CBF_PLD1.5 and CBF_PLD2.0 was recorded as δCBF. We performed regression analysis to understand the contribution of CBF, δCBF to CSVD imaging markers.

Results: We found that CBF derived from both PLDs was associated with WMH volume and the presence of lacune. CBF_PLD1.5 was significantly lower than CBF_PLD2.0 in CSVD patients, and δCBF was correlated with WMH volume but not the presence of lacune. Furthermore, CBF_PLD2.0 and δCBF were both associated with WMH in multiple regression analyses, suggesting an independent effect of delayed arterial transit. On an exploratory basis, we also investigated the relationship between venous disruption on δCBF, and we found that δCBF correlated with deep medullary veins score.

Conclusion: Both CBF and arterial transit were associated with WMH. ASL with multiple PLDs could provide additional hemodynamic information to CSVD-related studies.

Keywords: arterial transit; cerebral blood flow; cerebral small vessel disease; lacunes; white matter hyperintensities.

Figure 1

The relationship between CBFs and normalized WMH volume. (A–C) CBFs correlated with normalized WMH volume. The difference between the two CBF values became larger when WMH volumes increased. (D–F) δCBF in all three brain regions was associated with normalized WMH volume.

Figure 2

Two representative patients with different WMH burdens. Upper row: Patient A had a low WMH burden and presented with higher global CBF_PLD1.5 than CBF_PLD2.0. Lower row: Patient B had a high WMH burden and presented with lower global CBF_PLD1.5 than CBF_PLD2.0.