Emergency abdominal MRI: current uses and trends.

When evaluating the abdomen in the emergency setting, CT and ultrasound are the imaging modalities of choice, mainly because of accessibility, speed and lower relative cost. CT has the added benefit of assessing the whole abdomen for a wide spectrum of gastrointestinal disease, whereas ultrasound has the benefit of avoiding ionizing radiation. MRI is another tool that has demonstrated increasing utility in the emergency setting and also avoids the use of ionizing radiation. MRI also has the additional advantage of excellent soft-tissue contrast. However, widespread use of MRI in the emergency setting is limited by availability and relative cost. Despite such limitations, advances in MRI technology, including improved pulse sequences and coil technology and increasing clinician awareness of MRI, have led to an increased demand in abdominal MRI in the emergency setting. This is particularly true in the evaluation of acute pancreatitis; choledocholithiasis with or without cholecystitis; acute appendicitis, particularly in pregnant patients; and, in some cases, Crohn's disease. In cases of pancreatitis and Crohn's disease, MRI also plays a role in subsequent follow-up examinations.