An MRI (magnetic resonance imaging ) is a medical technique used in radiology to form pictures of the the biological process and the organs inside the body during both health and disease. MRIs do not use any type of radiation to take images, instead they use magnetic resonance which is safer and more accurate than other types of scanning.
MRIs are considered the safest and the best choice for patients, they are also widely used in hospitals and clinics for medical diagnosis, staging of disease and avoids the potential risks of radiation from serial multiphasic CT (computerized tomography) exams. MRI scans are usually compared to CT scans, which is a combination of a series of X-ray images taken at different angles; the CT uses a computer to create images from these X-rays. (Davis, C. 2018). MRIs provide more detailed information about the inner organs (soft tissues) such as the brain, skeletal system, reproductive system and other organ systems than is provided by a CT scan. CT scans are quick and painless, while MRI scans usually take longer time and produce loud noises for both the patient and the examiner. Almost anyone can have a CT scan without prior preparation, while some people with medical conditions cannot have an MRI scanning, such as those who have permanent metal implants inside their bodies. A CT scan is limited in detail when used for diagnosing soft tissue problems. In example, A physician will probably order a CT scan to check for bone fracture. If there’s no fracture found, the patient will most likely get an MRI to further check for any damage in tissues in the injured area for a more detailed picture and determine the best treatment for the patient.(Davis, C. 2018)
The major components of an MRI scanner are the main magnet, the gradient coils, the radio frequency coil and of course the computer which is usually placed outside of the MRI room. The main magnet is the most expensive part of the scanner. It creates a magnetic field ( An oscillating intensity of magnetic current) by passing a a very strong current through multiple coils that are inside the magnet. These coils are made of a very special kind of copper that pass magnetic currents which makes it very expensive. The gradient coils are located inside the main magnet. They create different magnetic fields around the three dimensions of the tested organ, These magnetic frequencies can oscillate in intensity to allow for the tissues to be scanned. scanned. The radio frequency (RF) coils transmit radio frequency (an oscillating rate of intensity of a current) waves on the body part whose image is being produced. The radio waves can be also focused on a specific part to produce a better image. Finally the scanner then sends the RF signals to a computer whose main function is to record and analyze the data, then translating it into understandable images of the patient’s body (Rashid, n.d.).
Anatomy of a closed MRI machine, (Rashid, 2018)
When an MRI is administered , the subject sits inside the machine, which creates strong magnetic field around the area to be imaged. The human body consists mainly of water. Water molecules (H2O) which contain whose hydrogen atoms consist of protons. The MRI machine applies a strong magnetic field,which makes the hydrogen atoms align and start spinning. The scanner also produces a radio frequency that creates a varying magnetic field. When the field is turned off, the protons of hydrogen atoms gradually return to their normal non excited state; this process is called precession. The contrast between several healthy and unhealthy tissues within an organ is determined by how fast the excited atoms return to their normal state. The change in radio frequencies is then sent to a computer that arranges the data and creates images of the patient’s tissues.
A picture from an MRI Report showing a liver tumor (shown by the arrow).(Tiferes, 2008).
In example, the below picture shows an MRI scan of a liver. The picture shows a mass on the left side of the liver indicated by the arrow. The physician later on can test this mass if it is cancerous. An MRI scan shows the different contrast of color in tissues due to the alignment of hydrogen atoms, allowing for a more detailed examination of each of the organ’s internal characteristics as well as secondary features. These features can be an abnormality of the blood flow into or out of the liver itself, such characteristics can confirm malignancy (the state or presence of a malignant tumor; cancer.). For patients undergoing frequent surveillance for lesions (An abnormal area of tissue inside or outside the body). MRIs taken over a period of time can show how the lesions change in shape. These lesions which get bigger or change their appearance may be also cancerous.(Alexander L. 2017). MRIs detect the appearance of primary hepatic malignancies in patients with and without a chronic liver disease to facilitate recognition of these tumors and to narrow the differential diagnosis when liver masses are encountered on abdominal imaging similar to the one shown in the picture.(Hornack, J. n.d.)
MRI is a noninvasive way for your doctor to examine your organs, tissues and skeletal system. It produces high-resolution images of the inside of the body that help diagnose a variety of problems. It is also the best procedure to examine the body without any cuts or surgical actions. Although it may come with some certain discomforts, it is a big help for a lot of patients worldwide.
References
Alexander, L. F., Harri, P., Little, B., Moreno, C. C., & Mittal, P. K. (2017, August 04). Magnetic Resonance Imaging of Primary Hepatic Malignancies in Patients With and Without Chronic Liver Disease: A Pictorial Review. National Center for Biotechnology Information. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5628780/
Davis, C. P. (2018, October 2). CT Scan vs. MRI Differences between Safety, Cost, and Uses. Retrieved from https://www.medicinenet.com/ct_scan_vs_mri/article.htm
Hornack, J. (n.d.). The Basics of MRI. Retrieved from http://www.cis.rit.edu/htbooks/mri/inside.htm
Lewis, T. (2017, August 11). What is an MRI (Magnetic Resonance Imaging)? Live Science. Retrieved from https://www.livescience.com/39074-what-is-an-mri.html
Magnetic Resonance Imaging (MRI). National Institute for Biomedical Imaging and Bioengineering.(n.d.). Retrieved from https://www.nibib.nih.gov/science-education/science-topics/magnetic-resonance-imaging-mri
Rashid, M. (n.d.). Components and functions of MRI. Retrieved from https://snc2dmri.weebly.com/components–functions.html
Tiferes, D. (2008, April). Liver neoplasms: Imaging characterization. Retrieved from http://www.scielo.br/scielo.php?pid=S0100-39842008000200012&script=sci_arttext&tlng=en
