Correcting versus resolving respiratory motion in free-breathing whole-heart MRA: a comparison in patients with thoracic aortic disease

Abstract

Background Whole-heart magnetic resonance angiography (MRA) requires sophisticated methods accounting for respiratory motion. Our purpose was to evaluate the image quality of compressed sensing-based respiratory motion-resolved three-dimensional (3D) whole-heart MRA compared with self-navigated motion-corrected whole-heart MRA in patients with known thoracic aorta dilation. Methods Twenty-five patients were prospectively enrolled in this ethically approved study. Whole-heart 1.5-T MRA was acquired using a prototype 3D radial steady-state free-precession free-breathing sequence. The same data were reconstructed with a one-dimensional motion-correction algorithm (1D-MCA) and an extradimensional golden-angle radial sparse parallel reconstruction (XD-GRASP). Subjective image quality was scored and objective image quality was quantified (signal intensity ratio, SIR; vessel sharpness). Wilcoxon, McNemar, and paired t tests were used. Results Subjective image quality was significantly higher using XD-GRASP compared to 1D-MCA (median 4.5, interquartile range 4.5–5.0 versus 4.0 [2.25–4.75]; p < 0.001), as well as signal homogeneity (3.0 [3.0–3.0] versus 2.0 [2.0–3.0]; p = 0.003), and image sharpness (3.0 [2.0–3.0] vs 2.0 [1.25–3.0]; p < 0.001). SIR with the 1D-MCA and XD-GRASP was 6.1 ± 3.9 versus 7.4 ± 2.5, respectively ( p < 0.001); while signal homogeneity was 274.2 ± 265.0 versus 199.8 ± 67.2 ( p = 0.129). XD-GRASP provided a higher vessel sharpness (45.3 ± 10.7 versus 40.6 ± 101, p = 0.025). Conclusions XD-GRASP-based motion-resolved reconstruction of free-breathing 3D whole-heart MRA datasets provides improved image contrast, sharpness, and signal homogeneity and seems to be a promising technique that overcomes some of the limitations of motion correction or respiratory navigator gating.

Measurement accuracy of prototype non-contrast, compressed sensing-based, respiratory motion-resolved whole heart cardiovascular magnetic resonance angiography for the assessment of thoracic aortic dilatation: comparison with computed tomography angiography

“…All of these studies used respiratory navigation to avoid breathing artifacts which, as mentioned in the introduction, may come with unreasonably long and unpredictable image acquisition time and a non-negligible failure rate [30][31][32][33][34]. Although respiratory self-navigation may sufficiently reduce acquisition time, the 1D nature of the superior-inferior self-navigation has its own shortcomings [12,24,25]. The novelty in the respiratory motion-resolved XD-GRASP reconstruction is that the image data can be acquired in a freebreathing fashion without the need for any kind of navigation or motion correction [24,28].…”

“…Twenty-four patients who had undergone a clinically indicated CTA between July 2017 and November 2018 for the evaluation and follow up of their known thoracic aortic dilatation, were prospectively enrolled for a research CMRA. Our study cohort partially overlapped with the image quality cohort reported before, comparing XD-GRASP to self-navigated whole heart CMRA [ 25 ]. General CMR exclusion criteria were applied to patient selection.…”

“…Several techniques have been proposed to overcome this difficulty and provide 100% scan efficiency, which in turn substantially shortens the acquisition time to 5-8 min [17][18][19][20]. Among those, respiratory self-navigation is one of the promising alternatives [21,22], however, this technique may suffer from artifacts among other potential limitations [23][24][25].…”

“…Such a technique has also been used to reconstruct 3D radial golden-angle coronary artery CMRA data acquired during free-breathing at multiple respiratory phases by exploiting the sparsity along the respiratory dimension [ 27 ]. While the image quality of radial XD-GRASP CMRA has been investigated in comparison to a radial self-navigated CMRA technique before [ 25 ], its ability to accurately evaluate quantitative cardiovascular parameters and monitor disease progression remains unestablished.…”

Motion compensated whole-heart coronary cardiovascular magnetic resonance angiography using focused navigation (fNAV)

“…As a result, an alternative reconstruction of 3D radial CMRA data was proposed wherein a respiratory signal is derived from repeated SI readouts, the k-space data are sorted in to multiple respiratory states and reconstructed as respiratory resolved images using eXtra-Dimensional Golden-angle RAdial Sparse Parallel (XD-GRASP) CMR [ 13 , 14 ]. While it has been shown that XD-GRASP provides sharper images than the 1D correction scheme, this approach may be adversely affected by residual uncorrected intra-bin motion, overregularization, and long computation times [ 15 ].…”