Prostate Cancer Characterization at Ultra-high Field MRI

Although the potential benefit of prostate examinations at 7 T including R2* mapping, 31P and 1H MRSI needs to be shown in clinical trials, our studies have exposed much more characteristics of prostate tissue in vivo. Using R2* mapping, chapter 3, it was shown that by diminishing potential artifacts and by higher spatial resolutions at 7T the measured R2* was closer to the intrinsic R2* than measured at 3T. The benefits of the higher spectral resolution were of importance while acquiring 1H MRSI of prostate cancer patients, here the separate detection of total choline and polyamines opened up the possibility for calculating the tCho/Cit ratio. Furthermore, the short echo time used at 7T revealed a total of 7 distinctive metabolites that could be detected and quantified in prostate tissue in vivo. In chapter 5, the combination of 1H and 31P MRSI in a single patient exam was shown for the first time. Lower levels of phosphoethanolamine (PE) in tumor areas compared to healthy tissue were detected, which particularly when combined with all of the newly obtained parameters might potentially give more information on tumor aggressiveness.