Simultaneous multi-slice readout-segmented echo planar imaging for accelerated diffusion-weighted imaging of the breast

Objectives: Readout-segmented echo planar imaging (rs-EPI) significantly reduces susceptibility artifacts in diffusion-weighted imaging (DWI) of the breast compared to single-shot EPI but is limited by longer scan times. To compensate for this, we tested a new simultaneous multi-slice (SMS) acquisition for accelerated rs-EPI. Materials and methods: After approval by the local ethics committee, eight healthy female volunteers (age, 38.9 +/- 13.1 years) underwent breast MRI at 3T. Conventional as well as two-fold (2x SMS) and three-fold (3 x SMS) slice-accelerated rs-EPI sequences were acquired at b-values of 50 and 800 s/mm(2). Two independent readers analyzed the apparent diffusion coefficient (ADC) in fibroglandular breast parenchyma. The signal-to-noise ratio (SNR) was estimated based on the subtraction method. ADC and SNR were compared between sequences by using the Friedman test. Results: The acquisition time was 4:21 min for conventional rs-EPI, 2:35 min for 2x SMS rs-EPI and 1:44 min for 3 x SMS rs-EPI. ADC values were similar in all sequences (mean values 1.62 x 10(-3) mm(2)/s, p = 0.99). Mean SNR was 27.7-29.6, and no significant differences were found among the sequences (p = 0.83). Conclusion: SMS rs-EPI yields similar ADC values and SNR compared to conventional rs-EPI at markedly reduced scan time. Thus, SMS excitation increases the clinical applicability of rs-EPI for DWI of the breast. (C) 2015 Elsevier Ireland Ltd. All rights reserved.