ABSTRACT
PET and MRI provide complementary data that are routinely analyzed concurrently in research and clinical applications. Recognizing the potential to combine the strengths of the two modalities while mitigating some of their limitations, approaches to combine PET and MRI in a single scanner have been proposed even before the first integrated PET-computed tomography (CT) scanners were developed. In recent years, there has been renewed and sustained interest in combining PET with MRI, perhaps as a result of the success and widespread clinical adoption of PET/CT. Given the completely different physical principles underlying these two imaging modalities, development of PET/MRI has faced even bigger technological and methodological hurdles than those PET/CT had to overcome in the first years after it was introduced. Just to give two examples, avoiding the mutual electromagnetic interference and the need for developing MR-based attenuation correction methods have been particularly difficult to address.
