Three‐dimensional quantitative T₁ and T₂ mapping of the carotid artery: Sequence design and in vivo feasibility

Abstract

The 3D T1 and T2 mapping of the carotid artery is feasible using variable flip angle and variable TE preparation acquisitions. We foresee application of this technique for plaque characterization and monitoring plaque progression in atherosclerotic patients.

Carotid Intraplaque Hemorrhage Imaging with Quantitative Vessel Wall T1 Mapping: Technical Development and Initial Experience

“…Thus, it may be more critical to evaluate the test-retest reproducibility of the GOAL-SNAP sequence since there is no reference standard for in vivo vessel wall T1 mapping. T1 of muscle measured here was similar to T1 assessed in the previous study (20), whereas T1 of normal vessel wall appeared to be different between studies (1117 msec vs 844 msec). Notably, Coolen et al (20) used a B1 mapping method with poor vessel wall depiction, which may have affected T1 estimation of the thin vessel wall.…”

“…Phantom imaging was performed by using nine tubes containing diluted gadopentetic acid with T1 values of 300–1500 msec, which was consistent with the estimated range of in vivo T1 values of carotid plaques at 3 T (9,11,20). Besides GOAL-SNAP imaging, T1 mapping was also performed by using a traditional 2D IR spin-echo (SE) sequence with the following parameters: repetition time msec/echo time msec, 5000/15; seven inversion times (50, 100, 200, 400, 800, 1600, 3200 msec); field of view, 100 × 100 mm; spatial resolution, 1.2 × 1.2 mm; section thickness, 6 mm; imaging duration, 50 minutes.…”

“…However, it is technically challenging due to multiple concurrent requirements, including blood suppression for vessel wall visualization, high spatial resolution and efficiency, and coregistration of separate images. To our knowledge, only one study has reported on vessel wall T1 mapping (20). When compared with the previous study, which used separate acquisitions with two flip angles for T1 mapping (20), the GOAL-SNAP approach avoids image registration and saves imaging time, and provides more T1 weighting, allowing for better model fit.…”

“…To our knowledge, only one study has reported on vessel wall T1 mapping (20). When compared with the previous study, which used separate acquisitions with two flip angles for T1 mapping (20), the GOAL-SNAP approach avoids image registration and saves imaging time, and provides more T1 weighting, allowing for better model fit.…”

“…A study of the modified Look-Locker IR sequence showed a coefficient of variation of 4.3%–4.8% for measuring T1 in phantoms (24). Coolen et al (20) performed vessel wall T1 mapping in six healthy volunteers and reported a coefficient of variation of 11%. Thus, it may be more critical to evaluate the test-retest reproducibility of the GOAL-SNAP sequence since there is no reference standard for in vivo vessel wall T1 mapping.…”