Multishot Diffusion-Weighted MRI of the Breast With Multiplexed Sensitivity Encoding (MUSE) and Shot Locally Low-Rank (Shot-LLR) Reconstructions. Journal of magnetic resonance imaging : JMRI Hu, Y., Ikeda, D. M., Pittman, S. M., Samarawickrama, D., Guidon, A., Rosenberg, J., Chen, S., Okamoto, S., Daniel, B. L., Hargreaves, B. A., Moran, C. J. 2020


BACKGROUND: Diffusion-weighted imaging (DWI) has shown promise to screen for breast cancer without a contrast injection, but image distortion and low spatial resolution limit standard single-shot DWI. Multishot DWI methods address these limitations but introduce shot-to-shot phase variations requiring correction during reconstruction.PURPOSE: To investigate the performance of two multishot DWI reconstruction methods, multiplexed sensitivity encoding (MUSE) and shot locally low-rank (shot-LLR), compared to single-shot DWI in the breast.STUDY TYPE: Prospective.POPULATION: A total of 45 women who consented to have multishot DWI added to a clinically indicated breast MRI.FIELD STRENGTH/SEQUENCES: Single-shot DWI reconstructed by parallel imaging, multishot DWI with four or eight shots reconstructed by MUSE and shot-LLR, 3D T2 -weighted imaging, and contrast-enhanced MRI at 3T.ASSESSMENT: Three blinded observers scored images for 1) general image quality (perceived signal-to-noise ratio [SNR], ghosting, distortion), 2) lesion features (discernment and morphology), and 3) perceived resolution. Apparent diffusion coefficient (ADC) of the lesion was also measured and compared between methods.STATISTICAL TESTS: Image quality features and perceived resolution were assessed with a mixed-effects logistic regression. Agreement among observers was estimated with a Krippendorf's alpha using linear weighting. Lesion feature ratings were visualized using histograms, and correlation coefficients of lesion ADC between different methods were calculated.RESULTS: MUSE and shot-LLR images were rated to have significantly better perceived resolution (P<0.001), higher SNR (P<0.005), and a lower level of distortion (P<0.05) with respect to single-shot DWI. Shot-LLR showed reduced ghosting artifacts with respect to both MUSE (P<0.001) and single-shot DWI (P<0.001). Eight-shot DWI had improved perceived SNR and perceived resolution with respect to four-shot DWI (P<0.005).DATA CONCLUSION: Multishot DWI enables increased resolution and improved image quality with respect to single-shot DWI in the breast. Shot-LLR reconstructs multishot DWI with minimal ghosting artifacts. The improvement of multishot DWI in image quality increases with an increased number of shots.LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 2.

View details for DOI 10.1002/jmri.27383

View details for PubMedID 33067849