Radiology Practice Test

Which imaging modality is less sensitive to motion artifacts than MRI?

1. X-ray

2. CT (Computed Tomography)

3. Ultrasound

4. Nuclear Imaging

The correct answer is: CT (Computed Tomography)

Computed Tomography (CT) is less sensitive to motion artifacts compared to Magnetic Resonance Imaging (MRI). This is primarily due to the mechanisms by which these two imaging modalities acquire images. CT imaging uses X-ray data collected around a patient from multiple angles and then reconstructs cross-sectional images through the body. This rapid acquisition provides a certain level of resilience to motion, as images are generated in a single sweep, thus minimizing the impact of any involuntary movements that may occur during the scan. In contrast, MRI relies on the alignment of hydrogen protons in a magnetic field and the subsequent collection of emitted signals. This process is more time-consuming and sensitive to movement, as even slight shifts can lead to significant artifacts in the final images. While X-ray, Ultrasound, and Nuclear Imaging also have some degree of resilience to motion artifacts, CT stands out for its combination of speed and the way in which it captures images, making it the preferred choice for patients who may have difficulty remaining still during imaging procedures.