0.55 T Magnetic Resonance Imaging in the Abdomen and Pelvis: Opportunities and Challenges.

As applications of MRI in the abdomen and pelvis have increased, access to MRI scanners has become more crucial. 0.55 T MRI scanners can potentially improve access by reducing the costs of MR systems and simplifying their siting requirements. These savings come with important tradeoffs, most notably decreased SNR efficiency. Decreases in SNR can be ameliorated to some degree by shorter T1 (faster repetition time), longer T2* (reduced susceptibility artifacts), and higher gadolinium relaxivity, which are found at lower fields. Reduced frequency separation between fat and water presents a particular challenge in imaging the abdomen and pelvis. In this article, we review how MRI at 0.55 T affects abdominal and pelvic imaging and discuss clinical examples of the liver, kidney, bile ducts, uterus, and ovary. We illustrate how metal artifacts are reduced at 0.55 T and discuss how deep learning image reconstructions, combined with free-breathing techniques, can overcome some of the limitations imposed by reduced SNR. We discuss future challenges and opportunities in this field, leveraging technological advances from other fields to bring MRI to more people who need it.