Highly efficient respiratory motion compensated free-breathing coronary mra using golden-step Cartesian acquisition

Abstract

Purpose: To develop an efficient 3D affine respiratory motion compensation framework for Cartesian whole-heart coronary MR angiography.Methods: The proposed method achieves 100% scan efficiency by estimating the affine respiratory motion from the data itself and correcting the acquired data in the reconstruction process. For this, a golden-step Cartesian sampling with spiral profile ordering is performed to enable reconstruction of respiratory resolved images at any breathing position and with different respiratory window size. Affine motion parameters are estimated from image-based registration of 3D undersampled respiratory resolved images reconstructed with iterative SENSE and motion correction is performed directly in the reconstruction using a multiple-coils generalized matrix formulation method. This approach was tested on healthy volunteers and compared against a conventional diaphragmatic navigator-gated acquisition using quantitative and qualitative image quality assessment.Results: The proposed approach achieves 47 ± 12 % and 59 ± 6 % vessel sharpness for the right (RCA) and left (LAD) coronary artery respectively. Also good quality visual scores of 2.4 ± 0.74 and 2.44 ± 0.86 were observed for the RCA and LAD (scores from 0-no to 4-excellent coronary vessel delineation). Not statically significant difference (p value of 0.05) was found between the proposed method and an 8mm navigator-gated and tracked scan although scan efficiency increased from 61 ± 10% to 100%. Conclusions: We have demonstrated the feasibility of a new 3D affine respiratory motion correction technique for Cartesian whole-heart CMRA that achieves 100% scan efficiency and therefore a predictable acquisition time. This approach yields image quality comparable to that of an 8mm navigator-gated acquisition with lower scan efficiency. Further evaluation of this technique in patients is now warranted to determine its clinical use.