Overview About MRI Paper Example

Introduction

In radiology, a medical imaging technique is used to form pictures of physiological processes of the body, and of the anatomy, both in disease and health called the Magnetic Resonance Imaging (MRI).In an overview of the scanners, MRI utilizes strong magnetic fields, radio waves, and magnetic field gradients to give rise to images of the body organs (Sato, Shirai, Taniguchi, Soutome & Bito, 2015). In differentiating it from CAT, PET scans or CT, for the MRI scans it does not involve the use of ionizing radiation or X-rays. Besides, Magnetic Resonance Imaging is regarded as a medical application that uses NMR for imaging in other forms like the NMR spectroscopy. MRI scan seems a better choice than going for CT scan despite having the X-rays hazards at some point in most medical contexts being well- controlled. For most medical diagnosis in clinics or hospitals, presenting of disease and follow-up with minimal exposure of radiation to the body then these MRI scans have widely been put to use. However, MRI scans seem to be connected to certain risks and discomfort as there is usually the need to be subjected to entering a narrow confining tube. It is also required to undergo a safety assessment before the process of MRI scans since persons with non-removable metals or medical implants in their bodies cannot safely undergo an MRI examination.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

The History of who invented the MRI lies on the foundation of the physics circumstances in the 1930s that lead to discoveries of NMR (nuclear magnetic resonance). For this technique, it had radio waves and magnetic fields that would result in atoms giving off tiny radio signals (Sato, Shirai, Taniguchi, Soutome & Bito, 2015). NMR was initially discovered by Felix Bloch and Edward Purcell which was later utilized as a procedure for studying chemical compounds composition. By 2003 Paul Lauterbur and Peter Mansfield got awarded for the discovery of Magnetic Resonance Imaging that evolved Science from the NMR spectroscopy of single dimension to spatial orientation of second dimension the MRI foundation. However, the first patent in the field of MRI was in 1970 by a medical doctor named Raymond Damadian who made discoveries concerning the use of Magnetic resonance imaging for medical diagnosis and gave it the nickname the indomitable. Damadian discoveries came after years of toiling to develop the MRI kind of machine that noninvasively scans an individual body while using magnets. The device constituted a superconducting magnet with a fashioned coil of antenna wires, and in a few decades, the use of these scanners proliferated.

In the medical field this Magnetic Resonance Imaging technology has since proven as the best choice because no radiation is used, but due to the strong magnetic field, it possesses some effects in the process. For instance, MRI is not an excellent choice to patients with cochlear implants, bone-growth stimulators, certain intrauterine contraceptive devices or any other types of implants that are iron-based as it puts the patients at high risks (Carlson, Neff, Link, Lane, Watson, McGee & Driscoll, 2015). It is also a technology with a presence of surgical clips as well as internal metallic objects thus likely to have adverse effects if used on a pregnant woman because the technique has the potential to increase on the amniotic fluid temperatures harmfully. Consequently, it is a technology with impact in the medical fields towards patients with epilepsy as well as allergens. In the case of allergens, there are impacts of a patient facing allergic reactions if contrast dye is used and other effects on patients suffering anemia, asthma, low blood pressure and sickle cell disease. Depending on an individual medical condition there are potential risks in the process; therefore there is the need before the procedure to discuss to your physician of any concerns.

Physiology of MRI

On the MRI physiology part on how it affects the cell is on the grounds of what it uses the radiofrequency and nuclear magnetic resonance that probes the structure and function of tissue with no ionizing radiation exposure. From clinical perceptive, the Magnetic Resonance Imaging has since developed in neuroscience to be the most significant diagnostic imaging modality. It has shown most benefits in the central nervous system with the radiofrequency signals penetrating the spinal column and skull to allow with it the tissues with minimal interference to become images. For the best visualization of the parenchymal abnormalities of the spinal cord or brain like tumors, infections, vascular lesions, and demyelinating lesions then MRI scans stand out. MRI techniques utilize signals from water constituting approximately two-thirds of the body weight of an individual thereby developing on brain structures and functions information.it is the positively charged particles the protons in the hydrogen molecules in water that give the signal due to the exposure to a strong magnetic field (Rooney, 2003)). After that, the structural MRI computes the nuclear magnetic resonance of water protons creating three-dimensional tissue images that appear computerized. Concretely, protons in the hydrogen atoms nuclei in water appear in motion amidst two points vibrating at the instance of exposure to a strong magnetic field. In the process, make absorption of energy in the radio waves frequency later remitting this particular energy in a similar radiofrequency when returning to their initial situation.

Physics of MRI

It concerns the primary physical MRI techniques considerations and technological characteristics of MRI devices. For the scanners to facilitate diagnosis and enhance the image then contrast agents intravenously or into a joint are injected. MRI has the ability to absorb specific atomic nuclei and when placed in an external magnetic field, emit radiofrequency energy. In close proximity to the anatomy being examined most often hydrogen atoms are used in generating a radiofrequency signal that is detectable and received by antennas. Specifically, in biological organisms like water and fat, hydrogen atoms appear abundant and also in human. It is with this reason that MRI scans primarily map in the body where to locate water and fat.

Radio waves pulses then awaken the nuclear spin energy transition together with magnetic field gradients localizing the signal. By differentiating the parameters of the pulse sequence, it generates different contrasts amidst tissues dependent on the hydrogen atoms relaxation properties. In the process magnetic moments of protons make alignment in two configurations parallel and towards the direction of the field; a radiofrequency pulse is then enforced exciting protons from parallel to anti-parallel alignment (Plewes & Kucharczyk, 2012). In reaction to the force, protons go through a precession under the influence of gravity, and later by the process of spin-lattice relaxation return to the low state of energy. It gives the impression of a magnetic flux yielding in the receiver coils a changing voltage giving the signal. The frequencies of protons resonating seem to rely on local magnetic fields strength whereby a stronger field correlates with higher frequency photons and a more significant energy difference. For the selection of specific slices to be imaged to be conducted an additional magnetic gradient is applied that vary linearly over space and after that, an image is acquired. Alternatively, because of magnetic Lorentz force, the gradient coils attempt to move creating loud knocking sounds and in this case requiring patients to wear hearing protection devices.

The Machine and its Principle of Work

MRI machine scans detailed images of the human body like cartilage, ligaments, tendons, muscles, and joints by using strong radio waves and magnetic fields thus detecting any injuries. In an examination with an MRI machine an individual is expected to lie on a movable table which slides into an opening like a tube while scanning the body part as various magnetic fields are introduced. The process with this machine is painless as a person cannot feel the radio waves or magnetic field being applied but in the process, the body reacts to the fields, and its relaxation after magnetic field removal is recorded and sent to a computer with information of where interactions happened. A multitude of these points undergoes sampling later computerized to create an image (Prince & Links, 2006). Nonetheless, during the scan, it produces much noise, so people use earplugs or music to block the noise. Some people who feel claustrophobic when in enclosed spaces are sedated to fall asleep and relax in the process of the machine scanning thereby avoiding movements that blur the images.

For this machine in its principle of how it works, it is not so complicated but on the idea that the human body is predominantly water. Human bodies are entirely made of water from the solid bones, lymph nodes and blood vessels tend to soak with water molecules. With water molecules are hydrogen nuclei that with magnetic field become aligned with each proton twisting its orientation. It is practical in the medical field wherein an instance when a health care provider turns the machine on the substantial forms of constant magnetic field remain intact for a period of measurement and when super strong fields are introduced the protons are lined up. From the aligning, it does not interfere with the chemical properties of the tissues; in this case, the reason being for a person's body to continue functioning as the doctor notes the measurement. The directions the protons align seem to have single and well-defined levels similarly to the manner in how the alignment of energy levels of electrons do in the nucleus of an atom. It is the thickness and hardness of a tissue that makes the time and amount of re-alignment changes where the water molecules sit. It also calls for careful monitoring of the arrival of photons re-emitted in the detectors of the MRI allowing identification of location and shapes of tissues. Since body parts have different levels of water, the MRI scan makes detection of the atoms electromagnetic fields in the molecules of water. It, therefore, uses that to recognize the disparities in tissues density and shapes in the entire body.

For this scanning technique, the MRI introduces about 0.2to 0.3 teslas of the strong magnetic field that aligns the proton spins. In the process, it also gives a radiofrequency current to create a different magnetic field as protons flip makes a spin upon absorption of energy. A process referred to as precession occurs when the field is turned off as protons gradually return to normal spin. In the process of returning it results in a radio signal measurable by receivers and in turn creates into an image. At very different rates protons on body tissues return to normal spins to enable the machine to determine various kinds of tissue. Usually, the settings of the scanner are adjustable to give contrasts allying different tissues on the body (Prince & Links, 2006). Besides, magnetic fields are utilized to provide 3-dimensional images giving the capability to view at all angles. In emphasizing on particular tissues or abnormalities then the use of multiple transmitted radiofrequency pulses is always applicable. However, an occurrence of a different emphasis happens since at different rates different tissues relax in the instance of switching off the transmitted radiofrequency pulse. At this juncture, the time for protons to fully relax is measurable in two ways initially is time taken for the return of magnetic vector to its resting condition called the T1 relaxation while the second is T2.

It is evident an MRI machine works under the principle of series of pulse sequences thus having tissues having different relaxation times separately identifia...