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MRI FINAL PRESENTATION
Transcript of MRI FINAL PRESENTATION
Images created during the Song Dynasty reflecting parts of the human body
An MRI Machine
An MRI is an internal imaging test used by physicians to help them diagnose patients. It is noninvasive and has increased in popularity in the recent years due to decreasing costs and fewer health risks than other imaging techniques. It employs powerful magnetic fields and uses varying radio frequencies to create an image of internal organs, which is rendered on a computer. However, the strong magnetic field makes it dangerous for patients to have any metal objects on them. If not careful, many can be seriously injured, if not killed. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121941/figure/FN0x9a27be8.0x99e4c80/
What Is An MRI?
Patient entering MRI scan
During an MRI scan, the patient lies down under the machine, and the exam generally takes 30-45 minutes. The patient is instructed not to move during the scan, as it messes with the quality of the images. Due to the strong magnetic field, anyone with a pacemaker has to have it set to a special mode compatible with the strong magnetic field. Generally, an MRI scan is conducted to look for soft tissue, such as a tumor, or internal bleeding of some sort.
How Does An MRI Work?
Components of An MRI
Unlike other forms of Medical Imaging, such as X-rays and CAT scans, MRI's do not use any high-energy electromagnetic waves, so they can be conducted more often and with less risk. It produces images much clearer than x-rays and ultrasounds, and comparable to CT scans. However, it is not the best option for producing images of softer tissues like the lungs. However, MRI's are much more expensive to conduct, as well as being more time consuming. Need more safety precautions due to magnetism.
MRI vs. Other Medical Imaging Devices
MRI FINAL PRESENTATION
By Jeremy Payano, Avery Lieber, Eloise Antoine, Filip Saulean and Rohan Kremer Guha
Historical Development (timeline)
Super Conductive Magnet
Roy M. Harrigan
Proton Nuclear Magnetic Resonance
The electromagnet, essential to the MRI machine. It is made of superconducting coils, which are cooled to -273 °C. These coils create larger magnetic fields than normal coils.
Founder of components of MRI in the work in magnetic levitation and electromagnetic energy coils. He tested the effects of magnetic levitation on the patients with arthritis.
Roy M. Harrigan patented the super conductive magnet in 1983. He was known for his work in magnetic levitation.
Electric Gradient Coils
Discovery of Magnetism
Magnetism was first observed in the form of a lodestone. Lodestone is a mineral magnetite which was first used by the Ancient Greeks in 600 BCE. They called the lodestone a magnet, and the discovery of magnetism has contributed to the development of scientific research. The magnetic field is what allows the MRI machine to work and the machine's parts are centered around it.
The lodestone, used by the Ancient Greeks
Hans Christian Oerstead
Paul Lauterbur and Sir Peter Mansfield
Damadian was the initial inventor of the MRI machine, by using a method know as potassium relaxation. This method, however, was quickly turned down because of the low quality of images.
These help to regulate the magnetic field produced by the superconductor magnet. This magnifies certain parts of the body.
Hans Christian Oerstead was a Danish physician and chemist who was instrumental in our current understanding of electromagnetism. He realized that magnetic fields could be created by electrical currents. Hans discovered this by using a copper wire (with a current running through it) to move a compass needle.
He earned his Ph.D in 1927 after he studied the magnetic properties of crystals. He worked on elaborating our understanding of the atomic nuclei's magnetic qualities during the 1930s and discovered the single states of the rotation of molecules and atoms. He also discovered both magnetic and mechanical moments of the atoms.
circa 600 BCE
Created Bloch equations, which calculate the nuclear magnetization as a function of time.
Bloch and Purcell found that when certain nuclei are placed in a magnetic field, they absorb energy in the electromagnetic spectrum, and re-emit this energy when the nuclei returned to their original state.
The strength of the magnetic field and the radio frequency matched each other according to the Larmor relationship.
Walter Gerlach and Otto Stern
Discovered "spin" of hydrogen atoms when exposed to a magnetic field.
Used Fourier transform to analyze radio-frequency emissions more precisely.
The two physicists were recognized and received the Nobel prize in 2002 for their work with the MRI. Paul Lauterbur came up
with the idea of the MRI while in a lecture. He wrote that shit on a napkin. The two were able to introduce gradients into magnetic waves. This allowed for the scientists to better understand how radio waves work relative to the nuclei. This was integral to the development of the MRI.
In the future, researchers are hoping to make machines autonomous, so that they are not controlled by technicians and are machine operated. In addition, researchers are looking to broaden the patients eligible for the exam, so in the near future, patients with pacemakers or other internal medical devices will be able to take the exam. These devices are also being designed so they can be MRI-safe, such as the Revo SureScan Pacemaker.
Schematic of experiment
Different types of MRI's
Monitors blood flow in the brain associated with neural activity. In doing so, it creates maps of brain activity, like pictured at right.
It was developed in the 1990's by Seiji Ogawa and Ken Kwong.
Diffusion MRI measures the diffusion of water through cell membranes
The Song Dynasty was a large influence in scientific research and analysis. They also advanced literature, and these two subjects seemed to influence each other. Imaging became more valued and began to be used in the medical field, and this advanced to become modern-day technologies like the PET scanner and the MRI machine.
Felix Bloch and Edward Mills Purcell
It is the main technique used in the MRI machines. It determines the framework of organic compounds by using an external magnetic field to line up the nuclei of atoms. The nuclei then return to their normal state and send out signals in a process called relaxation. The NMR spectrometer then read the signals.