RESUMO
BACKGROUND: The 3D breast magnetic resonance fingerprinting (MRF) technique enables T1 and T2 mapping in breast tissues. Combined repeatability and reproducibility studies on breast T1 and T2 relaxometry are lacking. PURPOSE: To assess test-retest and two-visit repeatability and interscanner reproducibility of the 3D breast MRF technique in a single-institution setting. STUDY TYPE: Prospective. SUBJECTS: Eighteen women (median age 29 years, range, 22-33 years) underwent Visit 1 scans on scanner 1. Ten of these women underwent test-retest scan repositioning after a 10-minute interval. Thirteen women had Visit 2 scans within 7-15 days in same menstrual cycle. The remaining five women had Visit 2 scans in the same menstrual phase in next menstrual cycle. Five women were also scanned on scanner 2 at both visits for interscanner reproducibility. FIELD STRENGTH/SEQUENCE: Two 3T MR scanners with the 3D breast MRF technique. ASSESSMENT: T1 and T2 MRF maps of both breasts. STATISTICAL TESTS: Mean T1 and T2 values for normal fibroglandular tissues were quantified at all scans. For variability, between and within-subjects coefficients of variation (bCV and wCV, respectively) were assessed. Repeatability was assessed with Bland-Altman analysis and coefficient of repeatability (CR). Reproducibility was assessed with interscanner coefficient of variation (CoV) and Wilcoxon signed-rank test. RESULTS: The bCV at test-retest scans was 9-12% for T1 , 7-17% for T2 , wCV was <4% for T1 , and <7% for T2 . For two visits in same menstrual cycle, bCV was 10-15% for T1 , 13-17% for T2 , wCV was <7% for T1 and <5% for T2 . For two visits in the same menstrual phase, bCV was 6-14% for T1 , 15-18% for T2 , wCV was <7% for T1 , and <9% for T2 . For test-retest scans, CR for T1 and T2 were 130 msec and 11 msec. For two visit scans, CR was <290 msec for T1 and 10-14 msec for T2 . Interscanner CoV was 3.3-3.6% for T1 and 5.1-6.6% for T2 , with no differences between interscanner measurements (P = 1.00 for T1 , P = 0.344 for T2 ). DATA CONCLUSION: 3D breast MRF measurements are repeatable across scan timings and scanners and may be useful in clinical applications in breast imaging. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1133-1143.
