On July 11th, 2013, New York Yankees shortstop Derek Jeter played in his first baseball game since fracturing his left ankle in October 2012. Unfortunately for Yankees fans, the future Hall-of-Famer didn’t make it through a single game before injuring another part of his body. This time, Jeter was forced to leave the game due to feelings of tightness in his quadriceps, a group of four muscles located in the thigh area. To determine if the injury was serious, Jeter will undergo a scanning procedure performed on millions of Americans each year – a magnetic resonance imaging scan, commonly known as an MRI.
The History Behind MRI Scans
While MRIs can certainly be considered a marvel of modern technology, the roots of this device date back to the 1940s. Around this time, physicists discovered the phenomenon of nuclear magnetic resonance (NMR). In this process, atoms emit radio signals after interacting with magnetic fields and radio waves. Interestingly enough, the two scientists directly responsible for discovering NMR did so independently of one another; Felix Bloch did his research at Stanford University, whereas Edward Purcell worked across the country at Harvard University. Subsequent researchers eventually used Bloch and Purcell’s work to study the makeup of chemical compounds.
As monumental as the discovery of NMR was to the world of science, it would take decades for scientists to find a medicinal use for it. The next step in the development of MRI technology would occur in 1970, courtesy of a professor at SUNY (State University of New York) Downstate Medical Center. The professor, Raymond Damadian, found that he could detect cancer cells in rats by using an NMR machine. Encouraged by his breakthrough, Damadian wasted no time in constructing a prototype device fit for human use. The fruit of the professor’s labor was the world’s first MRI scanner, a machine completed in 1977 and named the “Indomitable” by its creator.
Beginning in the early 1980s, MRIs became a fixture of hospitals throughout the developed world. Each year, over 60 million MRI scans are administered to patients, with about 30 million occurring in the United States alone.
How MRIs Work
The first thing you’ll probably notice about a modern MRI scanner is its imposing size and shape. The main section of the MRI machine resembles a large circular tube, technically known as the bore. Patients are placed into the bore with the aid of a wheeled table. Each patient enters the machine lying on his or her back, and remains in this position throughout the duration of the procedure. The part of the body that is to be examined is covered with a device called a coil.
Inside the bore, the patient is completely surrounded by a large and powerful magnet. After the patient has been placed into the MRI scanner, this magnet begins to move from side to side, developing images of the patient’s body. Unfortunately, performing this task requires the machine to emit a barrage of banging, humming and bumping sounds. This noise can be so overwhelming that patients are sometimes offered earplugs prior to being scanned. The patient may also be injected with special dyes to allow for higher quality images.
The magnet surveying the patient’s body is filled with electrical wire. During the MRI scan, electrical currents pass through the magnet’s wiring, causing a magnetic field to emanate from the magnet. The activation of the magnet also impacts the body’s hydrogen atoms, causing their nuclei to spin in one of two directions. It is at this point that the coil emits a radiofrequency, forcing the nuclei to spin in the opposing direction.
This change in direction might seem trivial, but it is this action that allows doctors to determine the damage (or lack thereof) in the affected body part. When these hydrogen molecules do their about-face, they release a considerable amount of energy. Likewise, this burst of energy gives off a number of energy signals, which are read and recorded by the coil. All of this information is transmitted to a computer, which transforms this data into a clear and coherent image.
The length of MRI scans can vary wildly. Some last for well over an hour, while others are complete in as little as fifteen minutes.
Health Problems Diagnosed By MRIs
If you are any kind of a sports fan, you’ve probably heard about athletes undergoing MRIs for a variety of reasons. In addition to providing relatively quick and accurate diagnoses, MRI scans are also able to examine health-related problems throughout the body. The following injuries and diseases are frequently diagnosed following an MRI scan.
- Brain aneurysms
- Damage to heart and lungs
- Breast cancer
- Lung cancer
- Blocked blood vessels
- Torn ligaments and tendons
- Spinal stenosis, disc bulges and tumors on the spine
- Bone tumors