Improved B1 homogeneity of 3 tesla breast MRI using dual-source parallel radiofrequency excitation.

Purpose: To compare breast MRI B₁ homogeneity at 3 Tesla (T) with and without dual-source parallel radiofrequency (RF) excitation. Materials and Methods: After institutional review board approval, we evaluated 14 consecutive breast MR examinations performed at 3T that included three-dimensional B₁ maps created separately with conventional single-source and dual-source parallel RF excitation techniques. We measured B₁ values (expressed as % of intended B₁) on each B₁ map at nipple level in multiple bilateral locations: anterior, lateral, central, medial, and posterior. Mean whole breast and location specific B₁ values were calculated and compared between right and left breasts using paired t-test. Results: Mean whole breast B₁ values differed significantly between right and left breasts with standard single-source RF excitation (difference L-R, Δ = 9.2%; P < 0.001) but not with dual-source parallel RF excitation (Δ = 2.3%; P = 0.085). Location specific B₁ values differed significantly between right and left on single-source in the lateral ( P = 0.014), central ( P = 0.0001), medial ( P = 0.0013), and posterior ( P < 0.0001) locations. Conversely, mean B₁ values differed significantly on dual-source parallel RF excitation for only the anterior ( P = 0.030) and lateral ( P = 0.0003) locations. Conclusion: B₁ homogeneity is improved with dual-source parallel RF excitation on 3T breast MRI when compared with standard single-source RF excitation technique. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]