1105 MR imaging sequences and clinical validation of a technique for respiratory motion correction in XMR-guided cardiac
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Meeting abstract
1105 MR imaging sequences and clinical validation of a technique for respiratory motion correction in XMR-guided cardiac catheterisations Andrew P King*1, Redha Boubertakh1, Kawal S Rhode1, Ying-Liang Ma1, Phani Chinchapatnam2, Gang Gao2, Tarinee Tangcharoen1, Matthew Ginks1, David J Hawkes2, Reza Razavi1 and Tobias Schaeffter1 Address: 1Kings College London, London, UK and 2University College London, London, UK * Corresponding author
from 11th Annual SCMR Scientific Sessions Los Angeles, CA, USA. 1–3 February 2008 Published: 22 October 2008 Journal of Cardiovascular Magnetic Resonance 2008, 10(Suppl 1):A230
doi:10.1186/1532-429X-10-S1-A230
Abstracts of the 11th Annual SCMR Scientific Sessions - 2008
Meeting abstracts – A single PDF containing all abstracts in this Supplement is available here. http://www.biomedcentral.com/content/pdf/1532-429X-10-S1-info.pdfThis abstract is available from: http://jcmr-online.com/content/10/S1/A230 © 2008 King et al; licensee BioMed Central Ltd.
Introduction We have previously developed an augmented reality system that provides an anatomical roadmap derived from MR imaging that is continually aligned to X-ray fluoroscopy images in the XMR hybrid imaging environment [1]. We have used this system to guide cardiac catheterisation for more than 50 clinical cases. This system provides an accuracy of 2 mm, but respiratory motion introduces errors that are typically much greater than this. In this abstract, we describe a novel technique for correcting for respiratory motion using a patient-specific motion model derived from MR imaging. Validation was performed on four volunteer and three patient datasets.
Methods Two MR imaging sequences are required to form the motion model: a 3-D high-resolution MRI for the anatomy and a dynamic near real-time scan to determine the respiratory motion. For the high-resolution dataset, a free breathing 3-D balanced TFE sequence is used, which is acquired at diastole during end-expiration. For the volunteers three additional high-resolution volumes were acquired at different respiratory positions for validation (typically, 120 slices, TR = 4.4 ms, TE = 2.2 ms, flip-angle = 90°, acquired voxel size 2.19 × 2.19 × 2.74 mm3, reconstructed to 1.37 × 1.37 × 1.37 mm3, 256 × 256 matrix). Two different dynamic scan sequences were applied,
which use respiratory navigators immediately before and after acquisition: Single volume -D TFEPI, typically, 20 slices, TR = 11.75 ms, TE = 5.84 ms, flip-angle = 20°, acquired voxel size 3.81 × 4.27 × 8.0 mm3, reconstructed to 2.22 × 2.22 × 4.0 mm3, 144 × 144 matrix, 100 dynamics; 2 sagittal slices Multislice balanced TFE, typically, TR = 2.74 ms, TE = 1.37 ms, flip-angle = 60°, acquired voxel size 1.78 × 1.75 × 8.0 mm3, reconstructed to 1.09 × 1.09 × 8.0 mm3, 320 × 320 matrix, 100 dynamics. The 2 sagittal slice sequence was tested because in our experience the dominant cardiac respiratory motion parameters are the inferior-superior and anterior-posterior translation
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