SWIFT Dual Breast Imaging Sequence and Coil with Interleaved Adiabatic Fat Suppression high temporal and spatial resolution #3369 Computer 8 breast imaging

SWIFT dual breast imaging sequence and coil with interleaved adiabatic fat suppression C. Corum 1, D. Idiyatullin 1, A. Styczynski-Snyder 1, C. Snyder 1, D. Hutter 1, J. C. Benson 2, L. Everson 3, L. Eberly 4, M. Nelson 3, and M. Garwood 1 1 CMRR, 2 Medical School, 3 Radiology, 4 Biostatistics University of Minnesota Minneapolis, MN, USA ISMRM 2013, Salt Lake City E-poster #3369, Computer 8, Tue 4/23, 10-11AM

3 What is SWIFT? SWeep Imaging with Fourier Transform Developed 2006 at University of Minnesota, Center for Magnetic Resonance Research

What is SWIFT? Spoiled steady state T 1 contrast Interleaved Preparations ISMRM 2009 ISMRM 2010 Short T 2 and T 2 * sensitive

SWIFT Sequence SWeep Imaging with Fourier Transform Simultaneous Excite Encode Acquire! (rapid time shared multiplexing) Fast and Efficient Short Dead Time (2-6 μs) short T 2 sensitive preserves off-resonance signal Flat Gradient w/smooth updates Quiet (low acoustic noise) PNS free (peripheral nerve stim.) Low eddy currents Immune to gradient timing errors 3D Radial Acquisition Undersampled KWIC reconstruction (Future) motion correctable (Future) compressed sensing

Motivation Improve Breast MRI (image quality and availability) We can use SWIFT for high spatial and temporal resolution MRI to simultaneously acquire… High Spatial Resolution Morphological Images High Temporal Resolution DCE Images …presenting improved image sets to Radiologists, and more efficient use of scan time for Breast MRI.

Goals Test and validate 4T transmit receive SWIFT compatible dual breast coil. Optimize SWIFT sequence and protocol for dual breast MRI at 4T. Optimize 3D view sharing based KWIC* reconstruction. Scan a pilot cohort of diagnostic patients. BI-RADS 4-5 * Dougherty et al., (2007). High frame-rate simultaneous bilateral breast DCE-MRI., Magn Reson Med 57 :

SWIFT 4T Dual Breast Coil 4 Tesla Dual Breast SWIFT Coil 4 receive channels Transmit/Receive (Q optimized) Low proton or short-T2 background materials RF Drive Configuration Equal phase splitter into 2 quad hybrids Individual T/R switches per channel

Coil Elements Each Side: Loop Element Helmholtz Element crossed to give circular polarized B 1 field. Decoupling capacitors are located between each element on a side and between the loop elements on left and right side.

Initial Testing 4 ms Gaussian CHESS Pulse Interleaved every 8 SWIFT views Breast phantoms consisting of Agar gel in center surrounded by vegetable shortening. Fat suppression failure due to over flipping 4 ms Gaussian CHESS Pulse Interleaved every 8 SWIFT views Normal subject for coil testing… Artifact in different place due to differing position relative to coil elements.

Solution MP-SWIFT with HS4R8* CHESS Pulse Interleaved every 16 SWIFT views *Garwood and Delabarre, JMR 2001 Phantom Image Hot spots are gone! Pulse is nominally set to degree flip Over flipping results in inversion, which still spoils fat on average.

High Resolution Patient Images Post Contrast Slice, Case 17Subtraction MIP, Case 17 SWIFT Dual Breast morphological imagingLesions are (biopsy proven) IDC 512^3 matrix, 0.75 mm isotropic resolution

SWIFT Breast MRI SLICE, Left Breast, Case 17Subtraction MIP, Left Breast, Case 17 SWIFT Dual Breast morphological imaging 512^3 matrix, 0.75 mm isotropic resolution

SWIFT Breast DCE Post Contrast MIP of SWIFT DCE, Case 17 cropped from Dual Breast session 6 sec frames 6 sec frames (shown 4 fps) 0.75 mm isotropic spatial resolution KWIC view sharing reconstruction, No other acceleration Same scan data as morphological images!

Conclusions SWIFT can be used for high spatial and temporal resolution bilateral breast MRI. Chess fat suppression with adiabatic HS8R4 pulse gives good performance, even with inhomogeneous local transmit coil needed for SWIFT SWIFT can provide high spatial and high temporal resolution KWIC reconstructions from the same raw data.

Discussion High spatial resolution dynamic contrast image series (DCE) open up new diagnostic possibilities. Hot spot analysis has improved spatial and temporal resolution. 4d MIPs and other novel data presentations (and associated analyses) are possible. It may be possible to achieve temporal resolution corresponding to frame to frame time < T 1 !!!

Thanks We gratefully acknowledge research support from the following NIH grants: R21 CA139688, S10RR023730, S10 RR027290, P41EB015894, and KL2 RR Thanks to Gregor Adriany and the UMN Physics Shop for initial coil mechanical design. Thanks to Ivan Tkac, Peter Anderson, Gregor Adriany, John Strupp and Brian Hannah for 4T system hardware and software support.

SWIFT Comparison Isotropic SWIFT, Case 4 Post contrast sagittal GRE, Case 4 SWIFT morphological, CASE 4 DCIS Similar in plane resolution, 256^3 matrix, 1.0 mm isotropic resolutionbut thicker slice. High resolution available at optimal contrast time

Single Breast SWIFT Cases Single Breast Coil Cases or matrix 1.00 mm or 0.67 mm isotropic resolution

Dual Breast SWIFT Cases Subtraction MIP, Dual Breast Coil Case 17Subtraction MIP, Dual Breast Coil Case matrix512 3 matrix0.75 mm isotropic resolution