Chapter 91 Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is an imaging method that provides a clear anatomic display of the body. This display provides excellent tissue discrimination, and the study may be done in any plane without the use of radiation. The MRI scan is found to be superior to the computed tomographic (CT) scan because MRI uses no radiation, and it depicts subtle contrasts between body tissues. Magnetic resonance images are created by sending radio waves to the child, who is lying in an external magnetic field. The image is created from interaction of the body tissue with the radio waves in the magnetic field. To prevent artifacts caused by movement, children are frequently sedated with either chloral hydrate or pentobarbital (Nembutal).
Client and environmental safety issues are paramount in the MRI room because the magnet is always on. The resulting magnetic field will attract any ferrous object (e.g., beepers, watches, infusion pumps, and oxygen tanks) into the scanner. Individuals are screened before entry for internal and external objects that may retain heat from the radio waves and cause burns.
NURSING ASSESSMENT
1. Screen child for pregnancy or implanted metal devices before scanning (metal devices may include, but are not limited to, metal pins or screws in bones, joints, or soft tissues; Harrington rod; pacemaker; and artificial heart valve).
2. Assess for adequate oxygenation during procedure if sedated.
