HIGH-RESOLUTION, FAT-SUPPRESSED, DIFFUSION-WEIGHTED MRI OF THE BREAST

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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. For breast MRI, with increasing resolution the readout time for conventional single-shot MR lengthens to the point that blurring and geometric distortions impair image acquisition. The strong gradients needed for diffusion-weighting (DW) worsen this problem. Parallel imaging can partially reduce these distortions, which was recently shown for breast MRI, using ASSET. Another approach is to use a multishot technique, such as SNAILS: a fat-saturated twice-refocused spin echo sequence with an analytically designed interleaved variable-density spiral readout trajectory, which has been applied successfully to high-resolution DWI in the brain. We assess its technical feasibility in the body, for breast MRI, and compare it to ASSET-DW-EPI in healthy volunteers to show ASSET-EPI and SNAILS diffusion-weighted images. Even with ASSET, DW-EPI was not possible at a 256x256 matrix size. SNAILS allowed distortion free acquisition of 256x256 resolution images. In addition, the high resolution and relative insensitivity to motion of SNAILS, allowed for high quality multiplanar reformats with the 'PET-like' contrast-reversal now popular in DWI screening studies. To read about other projects ongoing at the Lucas Center, please visit http://rsl.stanford.edu/ (Lucas Annual Report and ISMRM 2011 Abstracts)