Three-dimensional heart locator and compressed sensing for whole-heart MR angiography.
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ABSTRACT:
SUBMITTER: Moghari MH
PROVIDER: S-EPMC5292940 | biostudies-literature | 2016 May
REPOSITORIES: biostudies-literature
Publications
Three-dimensional heart locator and compressed sensing for whole-heart MR angiography.
Moghari Mehdi H MH Annese David D Geva Tal T Powell Andrew J AJ
Magnetic resonance in medicine 20150610 5
<h4>Purpose</h4>We sought to develop a whole-heart magnetic resonance angiography technique with three-dimensional (3D) respiratory motion compensation and reduced scan time.<h4>Methods</h4>A novel respiratory motion compensation method was implemented that acquires a 1D navigator (NAV) and a low-resolution 3D-image of the heart (3D-LOC) just before the angiography data. The central 10% of SSFP k-space was fully acquired using NAV-gating, and then 10% of peripheral k-space was randomly undersamp ...[more]
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Project description:PurposeTo develop a framework for respiratory motion-corrected 3D whole-heart water/fat coronary MR angiography (CMRA) at 3T with reduced and predictable scan time.MethodsA 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.ResultsAverage 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.ConclusionThe 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.
| S-EPMC6563440 | biostudies-literature
Project description:BackgroundPatients with thoracic aortic dilatation who undergo annual computed tomography angiography (CTA) are subject to repeated radiation and contrast exposure. The purpose of this study was to evaluate the feasibility of a non-contrast, respiratory motion-resolved whole-heart cardiovascular magnetic resonance angiography (CMRA) technique against reference standard CTA, for the quantitative assessment of cardiovascular anatomy and monitoring of disease progression in patients with thoracic aortic dilatation. METHODS: Twenty-four patients (68.6 ± 9.8 years) with thoracic aortic dilatation prospectively underwent clinical CTA and research 1.5T CMRA between July 2017 and November 2018. Scans were repeated in 15 patients 1 year later. A prototype free-breathing 3D radial balanced steady-state free-precession whole-heart CMRA sequence was used in combination with compressed sensing-based reconstruction. Area, circumference, and diameter measurements were obtained at seven aortic levels by two experienced and two inexperienced readers. In addition, area and diameter measurements of the cardiac chambers, pulmonary arteries and pulmonary veins were also obtained. Agreement between the two modalities was assessed with intraclass correlation coefficient (ICC) analysis, Bland-Altman plots and scatter plots.ResultsArea, circumference and diameter measurements on a per-level analysis showed good or excellent agreement between CTA and CMRA (ICCs > 0.84). Means of differences on Bland-Altman plots were: area 0.0 cm2 [- 1.7; 1.6]; circumference 1.0 mm [- 10.0; 12.0], and diameter 0.6 mm [- 2.6; 3.6]. Area and diameter measurements of the left cardiac chambers showed good agreement (ICCs > 0.80), while moderate to good agreement was observed for the right chambers (all ICCs > 0.56). Similar good to excellent inter-modality agreement was shown for the pulmonary arteries and veins (ICC range 0.79-0.93), with the exception of the left lower pulmonary vein (ICC < 0.51). Inter-reader assessment demonstrated mostly good or excellent agreement for both CTA and CMRA measurements on a per-level analysis (ICCs > 0.64). Difference in maximum aortic diameter measurements at baseline vs follow up showed excellent agreement between CMRA and CTA (ICC = 0.91).ConclusionsThe radial whole-heart CMRA technique combined with respiratory motion-resolved reconstruction provides comparable anatomical measurements of the thoracic aorta and cardiac structures as the reference standard CTA. It could potentially be used to diagnose and monitor patients with thoracic aortic dilatation without exposing them to radiation or contrast media.
| S-EPMC7871614 | biostudies-literature