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What is an MRI?

Magnetic resonance imaging (MRI) is a diagnostic technique that uses a magnetic field to produce pictures of structures inside the body.

During an MRI, your body is in a very strong magnetic field. The MRI machine also uses pulses of radio waves. The machine creates an image based on the way hydrogen atoms in your body react to the magnetic field and the radio waves. MRI signals can give an image of a single slice of any part of the body, much like a slice of bread in a loaf. Usually, images are created of several "slices" of an organ or part of the body. The MRI's computer also can combine these slices into three-dimensional (3-D) images.

Brain MRI and CT scans of two patients of the family.

Recommended MRI Textbooks

Image credit: Yang, Yang et al. “Genetic Identification Is Critical for the Diagnosis of Parkinsonism: A Chinese Pedigree with Early Onset of Parkinsonism.” PloS one vol. 10,8 e0136245. 21 Aug. 2015, doi:10.1371/journal.pone.0136245