Where are chemical shift cancellation artefacts most commonly observed?

Chemical shift cancellation artifacts occur primarily at interfaces where fat and water coexist, which is most commonly observed in cellular bone marrow and tissue-adipose interfaces. This phenomenon arises due to the difference in resonant frequencies between fat (lipid) and water molecules in an MRI environment. When images are obtained with specific echo times, areas where fat and water are present can cancel each other out due to phase differences, leading to distorted appearances or signal loss in those specific regions.

In cellular bone marrow, where fat-rich marrow is frequently adjacent to water-containing tissues, this interaction becomes pronounced, leading to noticeable artifacts. This cancellation effect is less prominent in major organs like the liver, which have a more uniform water content, and in vascular structures, where the rapid flow of blood typically minimizes such cancellation. Although areas with high water content can show artifacts at interfaces, the most significant effects are seen at fat-water boundaries, pinpointing why the option related to bone marrow and tissue-adipose interfaces is the most accurate choice.