Chapter 13: Diagnostic tests
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Magnetic resonance imaging (MRI)
Definition
Magnetic resonance imaging is a non‐invasive diagnostic scanning technique that provides cross‐sectional images of the body. The patient lies inside the bore of a very strong magnet, typically 1.5 tesla, although 3 tesla scanners are becoming increasingly prevalent. Protons in the body's water molecules spin or ‘precess’ when exposed to such a strong magnetic field. Radio waves are transmitted into the patient at the same frequency at which the protons are precessing and the patient transmits a signal, which is detected by a receiver coil (Chernecky and Berger [32], Pagana and Pagana [177]).
