Deep white matter hyperintensity is spatially correlated to MRI-visible perivascular spaces in cerebral small vessel disease on 7 Tesla MRI.

Abstract

Background: The association between perivascular space (PVS) and white matter hyperintensity (WMH) has been unclear. Normal-appearing white matter (NAWM) around WMH is also found correlated with the development of focal WMH. This study aims to investigate the topological connections among PVS, deep WMH (dWMH) and NAWM around WMH using 7 Tesla (7T) MRI.

Methods: Thirty-two patients with non-confluent WMHs and 16 subjects without WMHs were recruited from our department and clinic. We compared the PVS burden between patients with and without WMHs using a 5-point scale. Then, the dilatation and the number of PVS within a radius of 1 cm around each dWMH were compared with those of a reference site (without WMH) in the contralateral hemisphere. In this study, we define NAWM as an area within the radius of 1 cm around each dWMH. Furthermore, we assessed the spatial relationship between dWMH and PVS.

Results: Higher PVS scores in the centrum semiovale were found in patients with >5 dWMHs (median 3) than subjects without dWMH (median 2, p = 0.014). We found there was a greater dilatation and a higher number of PVS in NAWM around dWMH than at the reference sites (p<0.001, p<0.001). In addition, 79.59% of the dWMHs were spatially connected with PVS.

Conclusion: dWMH, NAWM surrounding WMH and MRI-visible PVS are spatially correlated in the early stage of cerebral small vessel disease. Future study of WMH and NAWM should not overlook MRI-visible PVS.