The History of MRI: How Magnetic Resonance Imaging Evolved
Updated: 4 days ago
MRI grew out of decades of physics research before it ever reached a hospital. The key science, called nuclear magnetic resonance (NMR), was discovered in the 1930s and 1940s. Scientists learned how to turn it into pictures of the body in the 1970s, and MRI scanners came into clinical use in the 1980s.
Here is a plain-language look at how MRI went from a physics lab to one of the most useful imaging tools in medicine.
The physics behind MRI
MRI is built on a simple idea. Some atoms, especially the hydrogen atoms found in water and fat, act like tiny magnets. When they are placed in a strong magnetic field and hit with the right radio waves, they absorb energy and then give off a signal. That signal can be measured.
Your body is full of water, so it is full of hydrogen. That is why MRI is so good at showing soft tissue. If you want to know more about the science, read our guide on how an MRI works.
1930s: Isidor Rabi and magnetic resonance
In the late 1930s, physicist Isidor Rabi at Columbia University measured magnetic resonance in beams of molecules. He showed that atomic nuclei in a magnetic field respond to radio waves at specific frequencies. Rabi received the Nobel Prize in Physics in 1944 for this work.
1940s: Bloch, Purcell, and NMR
In 1946, Felix Bloch and Edward Purcell, working separately, showed that nuclear magnetic resonance could be measured in liquids and solids, not just in molecular beams. They shared the Nobel Prize in Physics in 1952.
For the next few decades, NMR was mainly a tool for chemists. It helped scientists study the structure of molecules. It was not yet used to make pictures.
1970s: from signals to images
The 1970s were the turning point.
Raymond Damadian
In 1971, physician and researcher Raymond Damadian published a paper showing that NMR signals from tumor tissue were different from those of normal tissue in lab samples. This suggested NMR could help tell healthy tissue from diseased tissue. Damadian later patented an NMR-based method for scanning the body, and his team performed an early full-body scan of a person in 1977.
Paul Lauterbur
In 1973, chemist Paul Lauterbur published a method for making images with NMR. His key idea was to add magnetic field gradients, which vary the field strength across the sample. That way, signals from different locations could be told apart and turned into a picture.
Peter Mansfield
Physicist Peter Mansfield, in England, developed mathematical methods to analyze the signals and to make imaging much faster. His work led to a fast technique called echo-planar imaging, which is still important today.
Lauterbur and Mansfield shared the 2003 Nobel Prize in Physiology or Medicine for their discoveries about magnetic resonance imaging.
1980s: MRI enters hospitals
Commercial MRI scanners became available in the early 1980s, and hospitals began using them to image patients. Over time, the technique became known simply as MRI, or magnetic resonance imaging. The word "nuclear" was dropped, in part because people linked it with radiation, which MRI does not use.
Throughout the 1980s and 1990s, scanners improved in image quality and speed. Contrast agents were introduced to help certain tissues and blood vessels stand out more clearly.
1990s: functional MRI
In the early 1990s, researchers developed functional MRI, or fMRI. It detects changes in blood oxygen levels in the brain, which shift as different areas become active. This gave scientists a new way to study how the brain works without surgery or radiation.
Newer MRI techniques
MRI has kept evolving. Some newer methods include:
Diffusion imaging: tracks how water moves through tissue. One form, diffusion tensor imaging, helps map nerve pathways in the brain.
Susceptibility-weighted imaging: helps show small amounts of blood and certain minerals in tissue. Learn more about susceptibility-weighted imaging.
Brain volume analysis: software can measure the size of brain structures from an MRI.
Faster scans with computer help: new software, including artificial intelligence, is being used to speed up scans and improve image quality. Read more in the rise of AI in MRI.
A fun fact: the "tesla"
You may hear that an MRI machine is "1.5 tesla" or "3 tesla." The tesla is the unit used to measure magnetic field strength. It is named after inventor Nikola Tesla, who worked on electricity and magnetism. Tesla did not discover magnetic resonance, but his name lives on in every MRI magnet rating.
Why MRI's history matters to patients
MRI's story is one of many scientists building on each other's work over decades. The result is a test that can show the brain, spine, joints, and organs in detail without ionizing radiation. Today, doctors use MRI to look at injuries, nerve problems, tumors, and much more.
Frequently asked questions
Who invented the MRI?
No single person invented MRI. Rabi, Bloch, and Purcell discovered the physics. Damadian showed it could tell tissues apart. Lauterbur and Mansfield developed the methods for making images, and they won the 2003 Nobel Prize for that work.
When was the first MRI scan of a person?
An early full-body MRI scan of a human was performed in 1977. MRI scanners came into regular clinical use in the early 1980s.
Why is it called MRI and not NMR?
The technology is based on nuclear magnetic resonance. The word "nuclear" was dropped for medical imaging, in part because people linked it with radiation, which MRI does not use.
Does MRI use radiation?
No. MRI uses a magnetic field and radio waves, not ionizing radiation like X-rays or CT scans.
What is functional MRI?
Functional MRI, or fMRI, tracks changes in blood oxygen in the brain to show which areas are active. It is widely used in brain research.
Related reading
Schedule an MRI at Millenium MRI
Millenium MRI has centers in Ocala, Largo, and Tamarac, Florida, and in North Little Rock, Springdale, Jonesboro, and Marion, Arkansas. Our board-certified radiologists read every scan, and our ARRT-certified technologists will guide you through your visit. Same-day appointments are often available, and we accept most insurance plans, workers' compensation, personal injury cases, and self-pay.
This article is for general information and is not medical advice. Talk with your doctor about your specific situation.
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