Achieving Consistent, Homogeneous, Dark Fat Suppression on BilateralBreast MRI at 3.0 Tesla in the Clinical Setting

Abstract

Purpose: Effective fat suppression is a fundamental aspect of diagnostic quality breast MR for cancer screening but is challenging at 3T due to higher B0 and B1 magnetic field inhomogeneities compared with 1.5T. The purpose of this study is to describe a technique to achieve consistent homogeneous, dark fat suppression for T1 breast MR imaging at 3T for clinical breast cancer screening and evaluation. Methods: This was an IRB approved, HIPAA compliant study. Over 100 clinical breast MRI patients were scanned from May 2010 through October 2010, as part of routine clinical care, on a wide-bore 3T Magnetom Verio (Siemens Medical Solutions), One pre-contrast and two post-contrast axial VIBE scans were acquired for dynamic T1 imaging of the bilateral breasts. A longer TE of 4.9 ms was chosen empirically for optimal fat saturation. Two MQSA-certified breast radiologists, independently reviewed 20 consecutive MR studies. MR images were assessed for homogeneity of fat suppression and degree of fat suppression, both on a 5-point scale. A kappa coefficient was calculated for inter-reader agreement for both homogeneity of fat suppression and degree of fat suppression. Results: Overall, we found minimal unsuppressed fat and overall dark gray fat, indicating a high degree of fat suppression on 3T MR. Readers rated 3T fat suppression homogeneity as having minimal to no inhomogeneity in 80-90% of the examinations, with moderate agreement, (K=0.62, p<0.003), and fat suppression degree was rated having dark to very dark fat for all examinations with perfect agreement (K=1.0, p<0.001). Conclusion: Homogeneous, dark fat suppression on bilateral axial breast MRI can be obtained at 3.0T consistently in the clinical setting with minimal unsuppressed fat.