Purpose: Cerebral small vessel disease (SVD) leads to cognitive decline and is the most common vascular cause of dementia. Small arteries, particularly the lenticulostriate arteries (LSAs), are known to be involved in silent strokes. We aim to image the LSAs using a high-resolution 3D black blood T1 weighted (T1w) turbo-spin echo (TSE) sequence with variable flip angles (VFA) at both 3T and 7T.
Methods: Four healthy volunteers (1 female, 26±3 years) were scanned on both Siemens 3T Prisma and 7T Terra MRI systems using a 32-channel head coil. A 3D T1w TSE sequence with VFA was chosen for small vessel imaging with inherent excellent contrast between vessels and tissue due to good blood suppression properties. Black blood images were acquired with optimized imaging parameters at 3T (voxel size = 0.26x0.26x0.5 mm3 interpolated, slices=166, TE/TR = 12/1000 ms, ETL=41, scan time = 9:05 min) and 7T (voxel size = 0.5 mm3 isotropic, slices=288, TE/TR = 13/1430 ms, ETL = 40, scan time = 11:55 min). Contrast to noise ratio (CNR) was calculated to compare image quality between 3T and 7T.
Results and Discussion: Fig. 1 displays the LSAs using minimum intensity projection across 25 mm slices from a subject at 3T and 7T. Improved delineation of LSAs, especially distal regions, can be appreciated at 7T compared to 3T. Comparison of CNR for blood in the LSAs vs. the adjacent white matter between 3T and 7T (CNR: 9.1 vs. 15.5, 6.7 vs. 15.4, and 4.3 vs. 8.9 for the stem, middle, and distal regions, respectively) further demonstrated that LSAs imaged at 7T have better contrast in general and especially in the distal regions as noted by the colored arrows.
Conclusion: This preliminary study demonstrated the feasibility for visualizing LSAs in the human brain using high-resolution T1w TSE at 3T and 7T. Specifically, TSE at 7T provides better delineation of LSAs with better contrast between vessels and tissue. Our findings suggest this 7T TSE technique could be a promising imaging marker of cerebral small vessel diseases.