Motion corrected water/fat whole‐heart coronary MR angiography with 100% respiratory efficiency

Abstract

Purpose To develop a framework for respiratory motion‐corrected 3D whole‐heart water/fat coronary MR angiography (CMRA) at 3T with reduced and predictable scan time. Methods A 3D dual‐echo acquisition and respiratory motion‐corrected reconstruction framework for water/fat CMRA imaging was developed. The acquisition sequence integrates a 2D dual‐echo image navigator (iNAV), enabling 100% respiratory scan efficiency. Respiratory motion estimated from both the 2D iNAVs and the 3D data itself is used to produce nonrigid motion‐corrected water/fat CMRA images. A first study to investigate which iNAV (water, fat, in‐phase or out‐of‐phase) provides the best translational motion estimation was performed in 10 healthy subjects. Subsequently, nonrigid motion‐corrected water/fat images were compared to a diaphragmatic navigator gated and tracked water/fat CMRA acquisition. Image quality metrics included visible vessel length and vessel sharpness for both the left anterior descending and right coronary arteries. Results Average vessel sharpness achieved with water, fat, in‐phase and out‐of‐phase iNAVs was 33.8%, 29.6%, 32.2%, and 38.5%, respectively. Out‐of‐phase iNAVs were therefore used for estimating translational respiratory motion for the remainder of the study. No statistically significant differences in vessel length and sharpness ( P > 0.01) were observed between the proposed nonrigid motion correction approach and the reference images, although data acquisition was significantly shorter ( P < 2.6×10 –4 ). Motion correction improved vessel sharpness by 60.4% and vessel length by 47.7%, on average, in water CMRA images in comparison with no motion correction. Conclusion The feasibility of a novel motion‐corrected water/fat CMRA approach has been demonstrated at 3T, producing images comparable to a reference gated acquisition, but in a shorter and predictable scan time.

3D free‐breathing cardiac magnetic resonance fingerprinting

“…Moreover, translational motion correction can introduce artefacts originating from (incorrectly motion corrected) static fat tissue. 66 A SPIR pulse is used in this framework for fat suppression, but alternative approaches such as water selective excitations 67 could be considered for similar effect. Corrections using more complex respiratory motion models can also help in this regard.…”

Quantification of epicardial fat using 3D cine Dixon MRI

“…However, both navigator gating and slice tracking was employed for single-phase Dixon, where the navigator was performed immediately prior to the data readout for each cardiac cycle. Recent improvements in respiratory motion compensation techniques for whole-heart cine such as self-navigation are likely to prove bene cial in combination with cine Dixon for epicardial border delineation and can be included in future work to further improve this technique (22)(23)(24)(25)(26)(27)(28)(29).…”

Combined T2‐preparation and multidimensional outer volume suppression for coronary artery imaging with 3D cones trajectories

“…As discussed above, the proposed sequence could potentially remove the need for an additional fat saturation sequence in centric‐ordered 3D Cartesian trajectories. One example sequence is CASPR, which has already demonstrated promising motion correction and scan efficiency . There are also many sequences that use 3D radial trajectories with T 2 ‐prep for coronary imaging .…”

“…One example sequence is CASPR, which has already demonstrated promising motion correction and scan efficiency. 48,49 There are also many sequences that use 3D radial trajectories with T 2 -prep for coronary imaging. 9,50,51 The 3D radial trajectories have similar properties to 3D cones trajectories, and thus have similar benefits and tradeoffs.…”