When should abdominal magnetic resonance imaging be used?

When assessing the use of an imaging study, historically 2 criteria were used, diagnostic accuracy and cost of the study. However, as the awareness of risk for radiation-induced cancer in the general population increases as a direct result of more computed tomography (CT) studies being performed, reevaluation of the approach to imaging studies is necessary. The new imaging paradigm considers patient safety as an important aspect of assessing the role of an imaging modality. The primary goals of the new imaging paradigm should be diagnostic accuracy and patient safety, with the secondary goal being more affordable cost of study. in formulating a plan for when to use body magnetic resonance imaging (MRI), one has to consider all of these criteria and should also consider the question of when CT has unmatched diagnostic accuracy. The advantages of the spatial resolution of CT are mainly realized when there is great contrast between what is being looked for and background tissue; examples include small lung nodules and renal calculi. The greater intrinsic soft tissue contrast resolution and greater sensitivity for the presence or absence of intravenous contrast are appreciated in MRI studies, circumstances in which lesions occur within an organ without altering its exterior contour. This is well-shown for liver lesions. Adding patient safety into the equation, MRI should be indicated in exams in which there is no greater difference in diagnostic accuracy between CT and MRI, in patients with greater concern for radiation safety such as pediatric patients, and in cases of multiple or serial exams.