- Poster presentation
- Open Access
Motion corrected sensitivity encoded isotropic projection reconstruction (SNIPR) for whole-heart coronary MRA
© Pang et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Subjective Image Quality
- Image Quality Score
- Projection Reconstruction
- Iterative Image Reconstruction
- Respiratory Motion Compensation
As has been shown recently, the use of undersampled 3D projection reconstruction (3DPR) and image-based motion correction with 100% acquisition efficiency [1, 2] enables highly accelerated coronary MRA (CMRA) with high isotropic resolution. However, streaking artifact from undersampling significantly reduces the apparent signal-to-noise ratio (SNR). Moreover, affine motion correction distorts the k-space trajectory, hence introducing more streaking. In this work, the SNIPR reconstruction , a self-calibrated sensitivity encoding scheme for 3DPR, is integrated with image-based motion correction to reduce streaking artifacts and thus improve image quality.
MR data was collected using an ECG-triggered, T2-prepared, fat-saturated bSSFP pulse sequence with 3DPR trajectory and a 12 channel receiver coil array (TR/TE = 3.2 ms/1.6 ms, FOV=400 mm3, matrix size=3843, flip angle=90°, readout bandwidth=900 Hz/pixel). Three datasets were collected from each subject in random order with 5800, 11500 or 20500 lines (imaging times: 2.8±0.3, 5.6±0.6 and 9.5±1.2 min). Retrospective respiratory motion compensation was performed as previously described in . The coil sensitivity maps were calculated with the motion corrected data using Walsh's method . SNIPR extends the generalized SENSE framework described in  to 3D for iterative image reconstruction. Healthy volunteer scans (N=4) were performed successfully on a clinical 1.5T scanner (MAGNETOM Avanto, Siemens AG Healthcare, Erlangen, Germany) with IRB approval and written consent. Offline reconstruction was implemented in MATLAB (MathWorks, Natick, MA). Image quality scores were assigned by an experienced reader blinded to the underlying techniques.
Image quality score results (range: 0-4) for different reconstruction methods and undersampling factors.
Gridding, 5800 lines
SNIPR, 5800 lines
Gridding, 12000 lines
SNIPR, 12000 lines
Gridding, 20500 lines
SNIPR, 20500 lines
We have described a self-calibrated, motion-corrected 3D non-Cartesian sensitivity encoding reconstruction that greatly reduces streaking artifacts from undersampled 3DPR acquisitions, with isotropic 1 mm3 resolution and a 6 minutes scan time for whole-heart CMRA. Further studies are needed to characterize the noise performance of the proposed method. Also, the final image quality will benefit from improvements in motion correction and sensitivity map estimation, especially for highly undersampled datasets.
National Institute of Health grants nos. NIBIB EB002623 and NHLBI HL38698.AHA Postdoctoral Fellowship Award 11POST7390063.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.