American Registry of Radiologic Technologists (ARRT) Practice Exam

When lower sampling frequencies are used, aliasing artifacts indeed become more pronounced. Aliasing occurs when the sampling frequency is insufficient to capture the changes in the signal accurately. Lower sampling frequencies can result in the misrepresentation of higher frequency signals as lower frequency signals, leading to these artifacts.

In this context, aliasing artifacts do not disappear completely; rather, they can create confusion in how the image represents the actual anatomy or structure being examined. The lower the sampling rate, the more likely the artifacts will distort the true representation, making them more recognizable and problematic.

The factors that contribute to aliasing include the Nyquist theorem, which states that to accurately reproduce a signal, the sampling frequency must be at least twice the highest frequency present in the signal. Therefore, using a frequency that is lower than this threshold directly exacerbates the aliasing effect, leading to more pronounced artifacts.

Recognizing the influence of sampling frequency on image quality is essential for radiologic technologists to ensure optimal imaging and reduce diagnostic errors.