T2-weighted intracranial vessel wall imaging at 7 Tesla using a DANTE-prepared variable flip angle turbo spin echo readout (DANTE-SPACE)

Journal article

Purpose: To optimize intracranial vessel wall imaging (VWI) at 7T for sharp wall depiction and high boundary contrast.

Methods: A variable flip angle turbo spin echo scheme (SPACE) was optimised for VWI. SPACE provides black-blood contrast, but has less crushing effect on CSF. However, a delay alternating with nutation for tailored excitation (DANTE) preparation suppresses signal from slowly moving spins of a few mm/s. We therefore optimised a DANTE-preparation module for 7T. SNR, CNR and signal ratio for vessel wall, CSF and lumen were calculated for SPACE and DANTE-SPACE in 11 volunteers at the middle cerebral artery (MCA). An exemplar MCA stenosis patient was scanned with DANTE-SPACE.

Results: The 7T-optimised SPACE sequence improved vessel wall point-spread-function by 17%. The CNR between wall and CSF was doubled (12.2 versus 5.6) for the DANTE-SPACE scans compared to non-prepared SPACE. This increase was significant in the right hemisphere (p=0.016), but not in the left (p=0.090). CNR between wall and lumen halved, but remained at a high value (24.9 versus 56.5).

Conclusion: The optimised SPACE sequence improves VWI at 7T. Additional DANTE preparation increases contrast between wall and CSF. Increased outer boundary contrast comes at the cost of reduced inner boundary contrast.

Authors: Viessmann, O; Li, L; Benjamin, P; Jezzard, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Magnetic Resonance in Medicine
• Publication date: 2016-02-18
• DOI: 10.1002/mrm.26152
• EISSN: 1522-2594
• ISSN: 0740-3194
• Keywords: variable flip angle; Vessel wall imaging; black-blood imaging; SPACE; DANTE; plaque imaging; stroke