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

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.