Abstract
Hybrid PET/MR scanners are innovative imaging devices that acquire and fuse anatomical and functional data from magnetic resonance (MR), with metabolic information from positron emission tomography (PET). Integrated PET/MR scanners have the potential to greatly impact on medical research and patient management posing the most solid bases for a truly personalized imaging and then push forward the personalized medicine.
PET/MR performance is hampered by several factors and especially by motion artifacts and magnetic susceptibility artifacts that can degrade the quality of the images. In our clinical PET/MR practice, the PET/MR protocols were aimed to produce consistently high quality studies, to easy comparison at follow ups, and to reduce inter-operator variability in protocol scheduling in the case of difficult clinical questions. Fluoro 18- FDG is our main radioisotope for all body applications except for prostate adenocarcinomas where we prefer Fluoro-Choline (FCh) or PSMA; and Glutamate for pancreatic cancer.
PET/MR couples the advantages and PET/MR is not just another version of PET/CT; not only differences from the attenuation correction (AC) of PET would be different from CT (CT AC) and MR (MR AC); but also the total difference characters of MR. The non-contrast CT derived from PET/CT was usually used for co-registration only; but the non-contrast MR could provide many different data by using different pulse sequences, such as diffusion weighted image, ADC value (diffusion coefficient), MR spectroscope, T1 and T2 values and maps, texture analysis from both PET and MRI.
Furthermore, the role pf PET/MR would be more important in the near future. Not only the image hybrid, but also the “Hybrid Biomarker” from PET/MRI, such as MTV/ADCmin and/or SUVmax/Ktrans ratio, could play an important role as imaging biomarker of Precision Imaging. When we face the coming geriatric society and up-rising neurodegenerative and oncological population, we do need a precise image modality to examine human body; it is important for better compliance and one –stop examination, but also for “Precision Imaging” leading to ear of “Precision Medicine”.