Which method requires the patient to be kept still during the procedure?

Magnetic Resonance Imaging (MRI) requires the patient to remain still during the procedure because the imaging relies on the alignment of hydrogen atoms in the body’s tissues under a strong magnetic field. Movement can blur the images and lead to inaccurate or unusable results. The duration of an MRI scan can vary from 15 minutes to over an hour, depending on the area being examined, which makes it essential for patients to remain as motionless as possible for clear imaging.

Other methods mentioned may involve some degree of movement from the patient. Ultrasound, for instance, can often accommodate slight movement since it retrieves images in real-time using sound waves, allowing for adjustments during the procedure. Endoscopy typically requires the patient to be relatively still, but some procedures might allow for brief movements alongside the scope. A biopsy can be performed with varying degrees of patient movement depending on the method used and the area of the body being sampled. However, the critical aspect of the MRI is the necessity for complete stillness to obtain high-quality diagnostic images.