Through-time 3D radial GRAPPA for whole heart cardiac imaging

Abstract

POSTER PRESENTATION Open Access Through-time 3D radial GRAPPA for whole heart cardiac imaging Nicole Seiberlich 1* , Katherine L Wright 1 , Philipp Ehses 2 , Mark Griswold 3,1 From 15th Annual SCMR Scientific Sessions Orlando, FL, USA. 2-5 February 2012 Summary Through-Time 3D Radial GRAPPA can be used to reconstruct 3D CINE images covering the whole heart in a single breathhold. Background Through-Time Non-Cartesian GRAPPA has been pre- viously demonstrated for r eal-time 2D cardiac imaging (Seiberlich, et al. Magn Reson Med. 2011 Feb;65(2):492- 505.). This parallel imaging method works by acquiring several fully-sampled non-Cartesian datasets with a low temporal resolution, and using the coil sensitivity infor- mation from these datasets to reconstruct highly under- sampled non-Cartesian data acquired in real-time. By modifying this through-time non-Cartesian GRAPPA method to reconstruct highly undersampled 3D data, whole heart 3D CINE image s can be generated using data acquired in a single breathhold. Methods A total of 20 fully-sampled 3D stack-of-stars radial data- sets were acquired during free-breathing with no EKG gating using a 1.5T Siemens Espree and the following parameters: bSSFP sequence, TE=1.52ms, TR=3.04ms, matrix size = 128x128x20, projections/partition=128, FOV=300x300x90mm 3 , Flip Angle=45°, 5/8 Partial Four- ier, 18 receiver channels. Segmented undersampled data (using only 16 projections/partition, an acceleration fac- tor of R=8) were acquired with EKG gating and the above parameters during a breathhold for 15 heartbeats, resulting in 15 CINE frames. In order to perform the calibration, each of the time frames and partitions were employed as separate sources of calibration information; thus, a total of 300 repetitions could be used to generate the through-time GRAPPA weight sets. After recon- struction, the undersampled data yielded fully-sampled 3D CINE images, each with a temporal footprint of 48ms, an in-plane resolution of 2.3mm 2 , and a through- plane resolution of 6mm. The total acquisition time was 116s for the calibration and approximately 15 s for the breathhold CINE acquisition. Results Example images from diastole and systole of one healthy volunteer are shown in Figures 1 and 2. It is important to note that these represent just two of the 15 CINE frames acquired in this data set. Despite the high accel- eration factor (R=8 in comparison to the fully-sampled calibration data), the images demonstrate only minor residual aliasing artifacts. Because a 3D dataset is acquired, the images from each partition can be shown in the same cardiac phase, which is challenging when using multiple breathholds to acquire several 2D CINE slices. Conclusions By combining through-k-space calibration used in stan- dard parallel imaging with through-time calibration, undersampled 3D radial CINE datasets can be recon- structed to yield CINE images at similar temporal reso- lutionsas2DCINEimageswithcoverageoftheentire heart in a single breathhold. Funding The authors would like to acknowledge funding from Siemens Medical Solutions and NIH grants 1RO1HL094557 and 5K99EB011527. Author details 1 Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA. 2 High-field Magnetic Resonance, Max Planck Institute for Biological 1 Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA Full list of author information is available at the end of the article Seiberlich et al . Journal of Cardiovascular Magnetic Resonance 2012, 14 (Suppl 1):P279 http://www.jcmr-online.com/content/14/S1/P279 © 2012 Seiberlich et al; licensee 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. Cybernetics, Tübingen, Germany. 3 Radiology, Case Western Reserve University, Cleveland, OH, USA. Published: 1 February 2012 doi:10.1186/1532-429X-14-S1-P279 Cite this article as: Seiberlich et al .: Through-time 3D radial GRAPPA for whole heart cardiac imaging. Journal of Cardiovascular Magnetic Resonance 2012 14 (Suppl 1):P279. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit Fi gure 1 One o f t he 15 fram es acquired in t h e 3 D C INE d ataset showing 12 partitions of the heart in diastole. Figure 2 Another of the 15 frames acquired in the 3D CINE dataset showing 12 partitions of the heart in systole. Seiberlich et al . Journal of Cardiovascu lar Magnetic Resonance 2012, 14 (Suppl 1):P279 http://ww w.jcmr-online .com/conten t/14/S1/P27 9 Page 2 of 2