Magnetic resonance imaging in the critical care setting.

Magnetic resonance imaging (MRI) permits noninvasive multiplanar imaging with a large field of view, better soft tissue differentiation than is possible with CT, and assessment of both vascular lumen and wall without administration of contrast media or exposure to x-rays. Patients with renal or cardiac failure or allergy to radiographic contrast agents can be imaged safely. In the critical care setting, MRI is particularly useful in evaluating the major arteries and veins of the trunk, detecting and differentiating masses within skeletal muscle, detecting and characterizing subacute and chronic stroke or intracranial trauma, evaluating the spinal cord, and evaluating suspected CNS infection and CNS complications of AIDS. Limitations of MRI relate to bore size, examination time, and, above all, constraints of a high magnetic field environment.