Aliasing artifacts are caused by which of the following?

• A. Low receiver bandwidth
• B. FOV being smaller than area of excitation
• C. Improper trigger delay
• D. Patient metal implants

Answer: (B)

Aliasing artifacts occur when the field of view (FOV) is smaller than the area of excitation. This situation leads to the misrepresentation of data, where structures outside the FOV are incorrectly displayed within the image. Essentially, any anatomy that falls outside of the specified FOV can be "wrapped around" onto the image, creating the misleading appearance of additional structures or repeating patterns.

When the FOV does not adequately encompass the area being imaged, the information about those external structures isn’t fully captured. Instead, the system interprets the limited data available and projects it onto the FOV, leading to those characteristic aliasing effects, often seen as lines or patterns at the edges of the image, or even causing the same image to appear in multiple areas.

A low receiver bandwidth influences image quality by affecting noise levels but does not directly cause aliasing. Improper trigger delay relates to timing issues in capturing the image but is not associated with the fundamental issue of FOV and excitation area. Patient metal implants can create other types of artifacts, like distortion, but they do not inherently cause aliasing unless they somehow contribute to a misinterpretation related to the FOV’s coverage. Thus, the relationship between FOV size and area of excitation is