What is a characteristic appearance of chemical shift artefact in MRI images?

The characteristic appearance of chemical shift artifact in MRI images is observed as a bright band of signal at the low frequency side and a void at the high frequency side. This phenomenon results from the differences in resonance frequency between fat and water due to their differing chemical environments. In essence, this discrepancy causes fat and water signals to be misaligned when they are adjacent to each other, leading to a misrepresentation of the boundaries between these two tissues.

The bright band indicates where the fat signal is enhanced, while the void represents the area where the signals interfere destructively, showcasing the alignment difference caused by frequency shifts. This artifact can significantly affect image interpretation, particularly in areas where fat and water are closely apposed, like the abdomen or musculoskeletal regions, highlighting the importance of recognizing and understanding its appearance in clinical practice. Understanding this artifact is crucial as it assists radiologists and technologists in identifying and potentially mitigating its effects during MRI examinations.