Abstract
PurposeTo enable whole‐heart 3D coronary magnetic resonance angiography (CMRA) with isotropic sub‐millimeter resolution in a clinically feasible scan time by combining respiratory motion correction with highly accelerated variable density sampling in concert with a novel 3D patch‐based undersampled reconstruction (3D‐PROST).MethodsAn undersampled variable density spiral‐like Cartesian trajectory was combined with 2D image‐based navigators to achieve 100% respiratory efficiency and predictable scan time. 3D‐PROST reconstruction integrates structural information from 3D patch neighborhoods through sparse representation, thereby exploiting the redundancy of the 3D anatomy of the coronary arteries in an efficient low‐rank formulation. The proposed framework was evaluated in a static resolution phantom and in 10 healthy subjects with isotropic resolutions of 1.2 mm3 and 0.9 mm3 and undersampling factors of ×5 and ×9. 3D‐PROST was compared against fully sampled (1.2 mm3 only), conventional parallel imaging, and compressed sensing reconstructions.ResultsPhantom and in vivo (1.2 mm3) reconstructions were in excellent agreement with the reference fully sampled image. In vivo average acquisition times (min:s) were 7:57 ± 1:18 (×5) and 4:35 ± 0:44 (×9) for 0.9 mm3 resolution. Sub‐millimeter 3D‐PROST resulted in excellent depiction of the left and right coronary arteries including small branch vessels, leading to further improvements in vessel sharpness and visible vessel length in comparison with conventional reconstruction techniques. Image quality rated by 2 experts demonstrated that 3D‐PROST provides good image quality and is robust even at high acceleration factors.ConclusionThe proposed approach enables free‐breathing whole‐heart 3D CMRA with isotropic sub‐millimeter resolution in <5 min and achieves improved coronary artery visualization in a short and predictable scan time.
Highlights
Three-dimensional (3D) whole-heart coronary magnetic resonance angiography (CMRA)has shown significant potential for both diagnosis and characterization of coronary artery disease (CAD) without radiation exposure or the need for intravenous contrast [1,2,3].Previous studies have shown good diagnostic accuracy of conventional CMRA for the identification of significant CAD in the proximal-mid coronary segments compared to the non-invasive gold-standard computed tomography coronary angiography [4], demonstrating its effectiveness as a screening tool
The average imaging time for the fully-sampled 3D CMRA acquisition with isotropic resolution 1.2 mm3 was 22:30±4:54 with 100% scan efficiency, which was significantly reduced with 5-fold undersampling (4:11±1:03, P
compressed sensing (CS) and 3D-PROST reduce blurring and suppress noise artifacts compared to iterative SENSE (itSENSE). 3D-PROST further improved the delineation of the proximal segment of the RCA, achieving similar image quality to the fully-sampled reference
Summary
Three-dimensional (3D) whole-heart coronary magnetic resonance angiography (CMRA)has shown significant potential for both diagnosis and characterization of coronary artery disease (CAD) without radiation exposure or the need for intravenous contrast [1,2,3].Previous studies have shown good diagnostic accuracy of conventional CMRA for the identification of significant CAD (defined as luminal stenosis > 50%) in the proximal-mid coronary segments compared to the non-invasive gold-standard computed tomography coronary angiography [4], demonstrating its effectiveness as a screening tool. The low spatial resolution of conventional CMRA and its anisotropy impedes the quantification of luminal stenosis and hinders visualization of distal segments To address this challenge, isotropic sub-millimeter 3D CMRA is required for more accurate assessment of lesion severity and effective risk stratification of patients. Isotropic sub-millimeter 3D CMRA is required for more accurate assessment of lesion severity and effective risk stratification of patients Such imaging is not clinically feasible with conventional fully-sampled freebreathing diaphragmatic-navigated (dNAV) CMRA, used to minimize respiratory motion, due to excessively long and unpredictable scan times since only a fraction of the acquired data is accepted for reconstruction (referred to as scan efficiency) [5,6]. Several approaches have been proposed to compensate for respiratory motion and achieve 100%
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
