Assessment of the Virchow-Robin Spaces in Alzheimer disease, mild cognitive impairment, and normal aging, using high-field MR imaging

Abstract

Background and purpose: VRSs are the perivascular spaces surrounding the deep perforating arteries in the brain. Although VRS variations with age and disease pathologies have been reported previously, the radiologic characteristics of the VRS in relation to AD are poorly understood. This study investigated the prevalence, spatial distribution, and severity of the VRS in AD, MCI, and older adults who were CN. It also investigated the relationship of the VRS to white matter changes.

Materials and methods: Structural MR imaging data were acquired from 158 participants (AD = 37, MCI = 71, CN = 50, mean age = 74.97 ± 7.20 years) who had undergone T1WI at 3T. The severity of VRS in the white matter, basal ganglia, hippocampus, and brain stem structures was evaluated by using a semiquantitative scale, adapted from existing rating scales. A VRS total score summarizing the subscales was calculated to assess the whole-brain VRSs.

Results: VRSs were observed in multiple brain regions of all participants, typically presented as <2-mm well-margined symmetric round-, oval- and linear-shaped hypointensities on T1WI. The VRS total score increased with leukoaraiosis, atrophy, and advanced age (P < .001). Individuals with AD and MCI showed greater levels of VRS than control subjects. The VRS total score discriminated individuals with AD and those who were CN with an accuracy of 0.79 (95% CI, 0.69-0.89).

Conclusions: VRSs are common in older adults and are more severe in AD and MCI than in CN. Whether increased VRSs can be reliably used to aid in AD diagnosis warrants further investigation.

Fig 1.

Examples of the VRSs, white matter abnormalities, and atrophy in different regions of the brain. A, The VRSs in the basal ganglia region (score = 2). B, Magnified focal area in A. C, Magnified focal area in the frontal lobe in D (score = 2). D, The VRSs in the frontal and occipital lobes. E, Magnified focal area in the occipital lobe in D (score = 3). F, The VRSs in the brain stem (score = 2). G, Magnified focal area in F. H, The perivascular and deep white matter hypointensities (both scores = 3). I, Brain atrophy (score = 2)..

Fig 2.

Changes of the total VRS score as a function of age (A) and of the MMSE (B). The relationship of the VRS score with age (A) could be described by using linear regressions y = a + bx. Stars and the dashed line represent MCI (a = 3.70, b = 0.30, r = 0.30, P = .010), open circles and dotted lines represent CN (a = −18.33, b = 0.47, r = 0.47, P = .001), and filled circles represent AD (P > .05). The relationship of the VRS score with MMSE (B) could be described by using linear regressions y = a + bx for all subjects, where a = 28.33, b = −0.21, r = 0.20, P = .009.

Fig 3.

VRS total scores at different levels of leukoaraiosis. Significant differences are found among leukoaraiosis levels within each diagnosis.

Fig 4.

The ROC for the VRS score in identifying individuals with AD and CN (solid line: AUC = 0.789; 95% CI, 0.688–0.891). The dashed line represents AUC = 0.50.