Can a low b-value diffusion-weighted imaging sequence replace the standard T2-weighted fluid-sensitive sequence in breast MRI? A single-center prospective study.

OBJECTIVES

To determine whether a low b-value (b0) diffusion-weighted imaging (DWI) sequence of a similar acquisition time can fulfill the role of a T2-weighted/fluid-sensitive short tau inversion recovery (STIR) sequence.

MATERIALS AND METHODS

In this prospective, single-institutional study, participants underwent 3-T or 1.5-T breast MRI, which included a standard T2-weighted/fluid-sensitive short TI inversion recovery (STIR) sequence and an investigational DWI sequence (comprising readout segmented echo planar imaging (rs-EPI) and simultaneous multi-slice (SMS) imaging). Five radiologists independently scored 121 lesions on imaging by answering three questions assessing lesion conspicuity, lesion signal characteristics, and artifact grading. Statistical analysis included one-sample tests of proportions and Nelson's model kappa.

RESULTS

From 605 assessments in 72 patients (mean age, 48.3 ± 12.5 years [standard deviation]; 72 women), 537 (88.8%, p < 0.001) received assessments that lesion conspicuity on DWI was not inferior to STIR, 586 (96.9%, p < 0.001) received assessments that DWI followed the lesion signal characteristics on STIR, and 595 (98.3%, p < 0.001) received assessments that there were no or mild artifacts on DWI. Inter-reader agreement was substantial for similar lesion conspicuity (89.9%, к = 0.790, 95% CI: 0.76-0.82) and similar lesion signal characteristics (95.7%, к = 0.733, CI 0.69-0.77) on DWI and STIR, and moderate for whether there was mild/no artifact vs. moderate/substantial artifact on DWI (97.2%, к = 0.515, CI: 0.29-0.75).

CONCLUSION

Low b-value DWI provides similar diagnostic capabilities as T2-weighted/fluid-sensitive STIR, with comparable lesion conspicuity and lesion signal characteristics and without significant artifacts.

KEY POINTS

Question Can diffusion-weighted imaging (DWI) be incorporated into clinical 1.5-T and 3-T breast MRI protocols without adding acquisition time? Findings The signal characteristics and conspicuity of breast lesions on low b-value (b0) DWI were not inferior compared with that on standard T2-weighted/fluid-sensitive imaging. Clinical relevance The incorporation of low b-value DWI can translate to improved cost-effectiveness and patient experience of breast MRI by reducing false-positives and reducing overall scan time.