Phosphorus Magnetic Resonance Spectroscopy in Breast Cancer

At present, the risk of a woman developing invasive breast cancer during her life is about 1 in 8. This makes breast cancer the most prevalent type of cancer in women worldwide. As the risk of dying from breast cancer for a woman is about 1 in 36, early breast cancer detection and effective treatment are paramount in decreasing this risk. From preclinical studies and clinical studies in large tumors it is known that phospholipid- and energy metabolism are altered in cancer as compared to healthy fibro­glandular tissue. Phosphorus magnetic reson­ance spectroscopy (31P MRS) offers the possi­bility to measure a number of key metabolites involved in these processes in vivo. Unfortunately, the 31P MRS method is not very sensitive and requires that the magnetic field strength, the coil efficiency, the B1-field, and the pulse sequences used, are pushed to the limit, all to maximize the signal to noise ratio. The main theme of this thesis is pushing pulse sequences to the limit, to obtain the best signal to noise ratio possible in detecting phosphorus metabolites. To this end, direct detection, polarization transfer, multi-echo acquisitions and combinations of these methods are utilized. The work described in this thesis can possibly contribute to increasing the specificity of breast cancer detection and monitoring the efficacy of neoadjuvant therapy. A feasibility study of using 31P MRS in monitoring tumor metabolism during neoadjuvant chemotherapy forms part of this thesis.