Medical Imaging Explained: X-Ray, Ultrasound, CT and MRI

Medical imaging allows clinicians to examine structures inside the body without surgery. Different imaging methods use different technologies, so the most useful test depends on the clinical question.

X-ray

X-rays are commonly used for bones and certain chest examinations. The images are produced using ionizing radiation and are usually completed quickly.

Ultrasound

Ultrasound uses high-frequency sound waves. It can show movement in real time and is often used to examine soft tissues, organs and blood flow.

CT

Computed tomography combines many X-ray measurements to create detailed cross-sectional images. CT can provide more structural detail than a standard X-ray, but it also uses ionizing radiation.

MRI

Magnetic resonance imaging uses a strong magnetic field and radiofrequency signals rather than ionizing radiation. It can provide detailed views of many soft tissues.

Choosing the right test

There is no single imaging method that is best for every situation. The choice depends on the body area, the information needed, urgency and individual considerations.