Assessing breast MRI image quality: the bMRI-QUAL scoring system.

Abstract

The performance of breast MRI (bMRI) depends on image quality, varying due to patient-related or technical/protocol factors. The resulting artifacts can heavily reduce sensitivity and specificity. We developed a bMRI quality scoring system (bMRI-QUAL) for the bMRI standard protocol. Two independent readers with 3 years of experience evaluated 133 consecutive 1.5-T examinations (sample size calculated to ensure reproducibility). Each sequence was rated on a 4-point scale: 0 = not diagnostic; 1 = relevant artifacts with conserved diagnostic value; 2 = slight artifacts with conserved diagnostic value; 3 = excellent image quality. Each score was weighted in the following formula: (T2-weighted * 1) + (diffusion weighted imaging with b = 0 * 0.5) + (apparent diffusion coefficient maps * 0.5) + (T1-weighted-precontrast * 1) + (T1-weighted-postcontrast * 2) + (T1-weighted-subtracted * 3). This sum was divided by 2.4, obtaining a 0-to-10 global score (GS), with < 6 considered insufficient. The average GS between the two readers was 8.3 ± 1.0, with 102/133 examinations (76.7%) receiving a score ≥ 7 from both readers. Only one case (0.8%) was scored < 6 by both readers. The Bland-Altman analysis showed bias of -0.12, with limits of agreement ranging from -2.52 to +2.29. The difference in GS between the two readers (coverage probability) was 72/133 (54.1%) within ±1 and 123/133 (92.5%) within ±2. Coverage probability within ±1 point ranged from 94.0% to 99.2% across sequences. Average evaluation time/examination was 3 min. bMRI-QUAL is a reproducible quality scoring system. Breast MRI image quality at a tertiary cancer center was good to excellent in approximately 80% of cases. QuestionBreast MRI image quality varies widely and can compromise diagnostic accuracy. A standardized, clinically weighted scoring system is needed to guide repeat-scan decisions and facilitate quality assurance. FindingsIn 133 breast MRIs, the bMRI-QUAL 0-to-10 scoring system proved to be reproducible. Readers assigned a good-to-excellent mean score (8.3) with a 3-min evaluation time. Clinical relevancebMRI-QUAL provides a relatively fast and reproducible evaluation of breast MRI image quality, with each sequence weighted according to its clinical relevance for lesion detection/characterization. It can support decision-making regarding insufficient image quality and facilitate quality assurance protocols.