Side of contrast injection and breast size correlate with motion artifacts grade and image quality on breast MRI

Background: Motion is a relevant cause of artifacts in breast magnetic resonance imaging (MRI), potentially degrading image quality, even with optimized protocols. Purpose: To investigate the causes of motion artifacts (MA) impacting on image quality (IQ) of contrast-enhanced breast MRI. Material and Methods: Retrospective two-center study on consecutive 1.5-T contrast-enhanced breast MRI, independently reviewed by two radiologists on first subtracted and maximum intensity projection images to define the side most affected by MA. IQ was scored as 1 (optimal), 2 (reduced, but without reduction of diagnostic power), or 3 (reduced, with reduced diagnostic power). Correlations with injection side, breast size (A/B vs. C/D cups), patient age, clinical indication, and MRI scanner/protocol were assessed using χ2 and Fisher’s exact statistics. Results: In total, 237 examinations were included, with right injection performed in 124 (52%) and left in 113 (48%). MA were more frequent on the side ipsilateral to the injection (144/237, 61%, 95% confidence interval [CI] 54–67%) than on the contralateral (93/237, 95% CI 33–46%) (P < 0.001); IQ was scored 1 in 154/237 (65%), 2 in 63/237 (27%), and 3 in 20/237 (8%) examinations; patients with A/B cups showed higher IQ score than patients with C/D cups (scores 1, 2, and 3: 54% vs. 70%; 29% vs. 25%; 17% vs. 5%, respectively, P = 0.002). No significant correlations were found for MA (P≥0.106) or IQ (P ≥ 0.318) between ipsi- or contralateral injection and right/left injection, breast size, age, indication, or scanner/protocol. Conclusion: MA were more frequent in breasts ipsilateral to contrast injection and showed a reduced IQ for small breasts.