Radiology Practice Test

Which imaging method is least likely to be affected by patient movement?

1. X-ray

2. MRI

3. CT scan

4. Ultrasound

The correct answer is: CT scan

The imaging method that is least likely to be affected by patient movement is the CT scan. This can be attributed to the rapid acquisition of images that CT technology utilizes. During a CT scan, a series of X-rays are taken in quick succession as the patient moves through a rotating gantry. The entire image can often be captured in a matter of seconds, allowing the system to minimize the impact of minor patient movements. In contrast, MRI is particularly sensitive to patient movement because it relies on magnetic fields and radio waves to produce images; any movement during the scan can lead to motion artifacts that degrade the image quality. X-rays, while relatively quick, can still suffer from motion blur if the patient is unable to remain still. Ultrasound is also affected by movement, as the operator needs to maintain proper positioning of the transducer, and patient movement can disrupt the imaging process. Consequently, the rapid data acquisition and inherent technological capabilities of CT scans provide better resilience against patient movement, making it the imaging modality least likely to be affected in such circumstances.