Magnetic resonance imaging
Medical imaging technique using magnetic fields and radio waves.
Last updated
UCSF Health · CC BY-SA 4.0
Unlike CT and PET scans, MRI does not involve ionizing radiation.[1] It is a medical application of nuclear magnetic resonance (NMR).[1]
Quick Facts
- Field
- Radiology, Medical Imaging
- Key components
- Main magnet
- shim coils
- gradient system
- RF system
- Typical field strength
- 1.5 T to 7 T (clinical); up to 11.7 T (research)
- Contrast mechanisms
- T1 (spin-lattice) and T2 (spin-spin) relaxation
Facts from the source article.
Key facts and history
The technique relies on hydrogen atoms, which are abundant in water and fat, to generate a detectable signal.[2] In most medical applications, hydrogen nuclei create a signal processed to form an image based on their density in a specific region.[3] Exogenous contrast agents may be given to make the image clearer.[3] During a scan, an individual lies inside an MRI machine that generates a powerful magnetic field around the body region of interest.[3]
A temporary oscillating magnetic field delivers energy at the specific resonance frequency needed.[3] A radiofrequency pulse stimulates the atoms, and receiving coils then detect the resulting signal.[3] Differences in tissue contrast arise from how quickly excited atoms revert to their equilibrium state.[3] MRI emerged as a flexible imaging method during the 1970s and 1980s.[4]
What the cited sources add
A 2019 study led by Brian L. Edlow from Massachusetts General Hospital recorded an ultra-high resolution MRI dataset of an ex vivo human brain at 100 micron resolution.[5][6] The researchers hope to stimulate development of new ultra-high resolution imaging techniques for use in living subjects.[6] Another group at the University of Pittsburgh integrated the 100 micron MRI data with 3-dimensional tractography data to map human brain connectivity.[6]
References
- Wikipedia, "Magnetic resonance imaging" (CC BY-SA 4.0), which cites: Chang, "A new understanding on the development of MRI for cancer detection", Discover Physics, 2025; Rinck, "Magnetic Resonance in Medicine", www.magnetic-resonance.org, 2024 (we also read that source) en.wikipedia.org
- Wikipedia, "Magnetic resonance imaging" (CC BY-SA 4.0), which cites: "NMR Signal Reception: Virtual Photons and Coherent Spontaneous Emission", Concepts in Magnetic Resonance, 1998, p. 277–297 (original not read by us) en.wikipedia.org
- Wikipedia, "Magnetic resonance imaging" (CC BY-SA 4.0), which cites: "MRI from picture to proton", Cambridge University Press, 2007 (we also read that source) en.wikipedia.org
- Wikipedia, "Magnetic resonance imaging" (CC BY-SA 4.0), which cites: "Use of diagnostic imaging studies and associated radiation exposure for patients enrolled in large integrated health care systems, 1996-2010", JAMA, June 2012, p. 2400–9; "Health at a glance 2009 OECD indicators", 2009 (original not read by us) en.wikipedia.org
- "100-Hour-Long MRI of Human Brain Produces Most Detailed 3D Images Yet", 10 July 2019. facts only, no text reused. sciencealert.com
- "Team publishes on highest resolution brain MRI scan". facts only, no text reused. medicalxpress.com
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Magnetic resonance imaging (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Magnetic resonance imaging (CC BY-SA 4.0).
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