Which type of artefact occurs due to anatomy extending beyond the Field of View in MRI?

The correct choice relates to the phenomenon known as phase wrap artefact, which occurs when anatomical structures or signals extend beyond the Field of View (FOV) of the MRI scan. In MRI, the FOV defines the area in which data is collected and reconstructed. When anatomy extends beyond this defined area, the signals from those regions that lie outside can result in incorrect phase encoding, leading to wrap-around effects. As a result, structures that are actually located outside the FOV may appear within the image, causing confusing distortions and misrepresentations of anatomy.

Understanding this concept is critical in the practice of MRI because it highlights the need for appropriate selection of FOV based on the region of interest and the expected anatomy being imaged. Utilizing techniques such as increasing the FOV or adjusting the positioning of the patient can help to mitigate this artefact and ensure more accurate imaging results.