Quantitative H MRS of the Normal Human Breast

Introduction: The clinical utility of H MRS measurements in breast cancer is well-established: cancers are more likely to have a detectable total choline (tCho) resonance than benign lesions. Quantitative MRS methods have also found higher concentrations of tCho in cancers than in benign lesions. The question of whether tCho can be detected in normal (non-lactating) fibroglandular tissue has not been answered consistently in the literature. It has been reported that normal glandular parenchyma does not consistently show a tCho resonance at 1.5T (1), whereas at 3T, a broad 3.2ppm resonance can be measured in some normal fibroglandular tissues (2). Understanding the detectability and concentration of tCho in normal breast tissue is important, as this impacts measurements in lesions due to the unavoidable inclusion of some fibroglandular tissues in most MRS voxels. Furthermore, if tCho can be measured in normal subjects, they can be used as model subjects for developing new MRS acquisition and analysis techniques. In this work we aimed to measure tCho in normal fibroglandular tissues, quantity the tCho levels, and determine what factors impact the tCho detectability. Furthermore, we used these normal subjects to compare the performance of two single voxel spectral editing methods, TE averaging (3) and MEGA lipid suppression (4).