SELECTIVE REDUCTION OF CARDIAC ARTIFACT IN BREAST MRI

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Purpose: Cardiac motion causes significant artifact in breast MRI. Conventional slab saturation pulses cannot be applied to the heart without obscuring portions of the axillary breast tissue. We have implemented a 2D cylindrical saturation pulse that selectively saturates the heart and diaphragm. Methods: We collected data on six healthy volunteers at 1.5T (GE Healthcare, Waukesha, WI). A 2D excitation was applied with spiral gradients in both x and z for an elliptical cylindrical superior-inferior prescription encompassing the heart. Gradient crushers followed the cylindrical excitation, thus dephasing and reducing the signal from the selected area. The heart saturation pulse was followed by a dual band spectral spatial RF pulse for bilateral breast excitation, and a 3D variable-density stack of spirals for acquisition. The TR for the saturation pulse is 12 ms, in addition to the 32 ms bilateral spiral pulse. For analysis, three ROIs were drawn in each image: one in the heart, one in the glandular breast tissue, and one in the image background. To calculate the signal emanating from the outer area, the standard deviation of the outer ROI was normalized by dividing by the mean signal from the breast ROI. To read about other projects ongoing at the Lucas Center, please visit http://rsl.stanford.edu/ (Lucas Annual Report and ISMRM 2011 Abstracts)