Background: Breast MRI protocols have been improved by using a combination of dynamic scans for bilateral breasts and high-resolution imaging for a single breast which can be obtained during dynamic scans by recent technological advances. The purpose of this study was to compare high-resolution imaging during dynamic scans (HR-intra) with high-resolution imaging obtained post dynamic scans (HR-post).
Methods: Fifty-five women with pathologically proven breast cancer who underwent breast dynamic scans at 3-T MRI from February to September 2009 were enrolled in this study. Tumoral contrasts to the background breast tissue were compared by three radiologists independently in a blinded fashion. Results of visual assessment were categorized into three groups as follows: HR-intra being better (IB), equal (E), and HR-post being better (PB). The contrast to noise ratio (CNR) of the tumor and the signal to noise ratio of the normal breast gland (SNR) were compared between HR-intra and HR-post.
Results: Two patients were excluded because of poor MR imaging quality. Three radiologists separately categorized 64.2, 79.2, and 77.4 % of lesions as IB. The CNR of the tumor of HR-intra (mean ± SD = 6.9 ± 4.0) was significantly higher than that of HR-post (6.0 ± 3.7, p < 0.0001). The SNR of the normal breast gland of HR-intra (9.5 ± 1.7) was significantly lower than that of HR-post (10.0 ± 1.9, p < 0.0001).
Conclusion: HR-intra during dynamic MRI provided earlier and better tumor to normal breast gland contrast than HR-post.