chemical shift artifact
MRI artifact causing spatial misregistration between fat and water signals, particularly visible at tissue interfaces.
Full Definition
Chemical shift artifact occurs in MRI due to the different resonance frequencies of fat and water protons, resulting in spatial misregistration between fat and water signals along the frequency-encoding direction. This artifact appears as a bright or dark rim at interfaces between fat-containing and water-containing tissues. The severity depends on field strength, bandwidth, and sequence parameters. While often considered an artifact, chemical shift can also be exploited diagnostically, such as in chemical shift imaging for adrenal adenoma characterization or in detecting microscopic fat in lesions.
Usage
Usage note: Distinguish from pathologic enhancement; explain when artifact may mimic disease.
In Context
- "Chemical shift artifact at the kidney-fat interface created apparent rim enhancement." — MRI artifact explanation
- "The apparent hyperintense rim was attributed to chemical shift artifact rather than pathologic enhancement." — Image interpretation clarification