Aliasing occurs when?

Aliasing occurs when the field of view (FOV) used in imaging is smaller than the actual area being excited or imaged. This situation leads to a misrepresentation of the spatial frequency information, causing structures that extend beyond the FOV to appear wrapped around or duplicated within the image. This visual artifact is particularly common in sequences where sampling occurs over a finite period, and if the sampling frequency is not adequate to capture all the frequency information present, the result is a misinterpretation of location.

In terms of imaging perspectives, when the FOV is truncated while the object or area being studied extends beyond it, not all data points are correctly captured, leading to aliasing artifacts. Recognizing the relationship between spatial resolution, field of view, and sampling frequency is essential in order to avoid misrepresentations in diagnostic imaging, which can affect clinical decision-making.

The other factors listed, while they may introduce various imaging issues, do not specifically cause aliasing. A thick imaging slice can result in reduced detail or partial volume artifacts but does not necessarily relate to aliasing. Inconsistent timing of RF pulses can cause timing issues or image blurring, and a faulty receiver coil could lead to noise or signal loss, rather than aliasing.