MarkVCID

MarkVCID is a consortium of US academic medical centers set up by NINDS and NIA in 2016 to validate biomarkers of cerebral small vessel disease, the main driver of vascular contributions to cognitive impairment and dementia (VCID). The first phase (MarkVCID1, 2016-2020) tested the reliability of 11 imaging and fluid biomarker kits. The second phase (MarkVCID2) follows newly enrolled participants every year to validate five of them clinically. Massachusetts General Hospital runs the coordinating center, which shares de-identified imaging, clinical and cognitive data and biosamples with outside researchers.

Composition

MarkVCID1 enrolled 653 participants at six research sites, and 90% came back for at least one follow-up visit. In MarkVCID2, nine performance sites drawn from 15 medical centers each aim to enroll at least 200 people with cognitive complaints or early cognitive impairment that may relate to small vessel disease; the number enrolled so far is not published. The data search forms list baseline, 12-month and 24-month visits, syndromic diagnoses from normal cognition to dementia, demographics, vascular risk factors, cognitive tests, lab values and OCTA retinal scans. Counts per sequence, diagnosis, sex or age are not published.

Acquisition

The harmonized 3 T protocol has a sagittal four-echo ME-MPRAGE (1 mm), a sagittal 3D FLAIR (1 mm), axial diffusion imaging, a sagittal 3D multi-echo T2* GRE (6 or 8 echoes, TE about 3 to 21 ms, 1.2 mm isotropic, magnitude and phase kept for SWI or QSM), a 3D T2w scan and BOLD cerebrovascular reactivity with brief CO2 inhalation. Parameters were set for Siemens Trio and Prisma and Philips Achieva, with a GE 750W variant that uses an axial SWAN GRE. Sites are certified and scan the ADNI phantom every two months. The protocol adds test-retest rescans and cross-scanner scans of small subsets to measure reliability.

Annotations

No manual lesion labels are described. Biomarker kits produce white matter hyperintensity volume, peak skeletonized mean diffusivity, free water, the ARTS score and cerebrovascular reactivity maps.

Known limitations

• Images are not openly available; every project needs Steering Committee approval and a DUA.
• The participant count covers MarkVCID1 only, and the number with each MRI sequence is not published.
• Microbleeds are a target of the GRE sequence, but no released microbleed reads are described.