Henze Bancroft, Leah C. (The University of Wisconsin - Madison) “High Resolution Magnetic Resonance Imaging of the Bilateral Breasts Using an Accelerated 3D Radial Trajectory” (2014)

Henze Bancroft, Leah C. (The University of Wisconsin - Madison) “High Resolution Magnetic Resonance Imaging of the Bilateral Breasts Using an Accelerated 3D Radial Trajectory”, Advisor: Block, Walter F. (2014)

Breast cancer is the most commonly diagnosed cancer in women in the United States after skin cancer. MRI has been proven to be highly sensitive to breast cancer however it suffers from moderate specificity, resulting in an increased number of false positive. There is the potential to improve the differential diagnosis of breast lesions through better depiction of the morphologic features of interest as well as improving the depiction of contrast kinetics through improved temporal resolution in the DCE scan.

This work utilizes the rapid and efficient 3D-radial VIPR pulse sequence to speed the acquisition of MR breast images, allowing for higher spatial and temporal resolution. A Balanced Steady State Free Precession (bSSFP) signal model is developed to combine bSSFP imaging with chemical shift based decomposition, producing robust fat suppression despite large field inhomogeneities in short acquisition times. This model is designed to handle the complex signal behavior expected when a multiple peak spectral fat model is modulated by the frequency response of a bSSFP acquisition. The ability of this model to accurately decompose fat and water is demonstrated in a phantom as well as in vivo imaging at 1.5 T.

This signal model is used in conjunction with a bSSFP implementation of VIPR to provide images with T2-like contrast and high 0.63 mm isotropic resolution with robust fat suppression across both breasts in a six minute scan time at 1.5 T. The VIPR pulse sequence is modified to provide bilateral coverage and accommodate the collection of four half echoes for use in chemical shift based fat/water decomposition using an iterative graph cuts algorithm. Results are demonstrated in normal breast volunteers.

Finally, VIPR is used to provide high temporal and isotropic spatial resolution during DCE breast imaging. A previously developed version of VIPR was used to obtain promising high spatial and temporal resolution results. Sensitivity to motion and low SNR when using this method provided motivation for the development of bilateral VIPR IDEAL described in this work. While a more thorough analysis of the temporal settings remains to be done, initial results from an ongoing post-contrast study are presented here.