Which imaging modality uses radio waves and magnets to create detailed images of the brain and spine?

• A. Skull X-Ray
• B. PET Scan
• C. Magnetic Resonance Imaging (MRI)
• D. Myelography

Answer: (C)

Magnetic resonance imaging uses magnets and radio waves to create detailed images of the brain and spine. In MRI, a strong magnetic field aligns the body's hydrogen protons. A short burst of radiofrequency energy then perturbs this alignment, and as the protons realign, they emit signals that are captured to form images. Different tissues return to alignment at different rates, which gives MRI its excellent soft-tissue contrast—perfect for detailing brain structures, spinal cord, discs, ligaments, and other supporting tissues. It doesn’t use ionizing radiation, which is another advantage for repeatedly imaging delicate areas like the brain and spine. By contrast, skull X-rays mainly show bones, PET scans map metabolic activity with radioactive tracers, and myelography uses injected contrast with X-ray or CT to visualize the spinal canal—less ideal for soft-tissue detail. So the described modality is MRI.