What is MRI? Magnetic resonance imaging, aka MRI, is a scanning technique to produce detailed 3 dimensional anatomical images of the human body in any direction by using a magnetic field and radio waves. The pictures provide information that can be useful in diagnosing a wide variety of diseases and conditions. Radio waves cause the molecules to create faint signals that are used to view the body in narrow, axial slices. How does MRI Work?An MRI scanner has a large magnet with a tube shaped tunnel through the middle. The MRI machine picks up signals from the nuclei of the hydrogen atoms in the body.
A computer converts these signals them into a black and white picture. The magnets from the MRIs develops a strong magnetic field that makes the protons to align with the field. When the radiofrequency pulses are sent in, the protons are stimulated and makes them non-equilibrium, a state of the chemical reaction in which the opposing forces are not balanced. When the pulses are off, the particles produce electrical signals that are picked up by the MRI sensors which can identify the energy released.
When the body is placed in the magnetic field of the magnetic resonance imaging machine, it realigns hydrogen molecules which is magnetic. The radio wave disrupts the atoms’ polarity. The MRI sensors detects the time span for the atoms to align to the original alignment.
How long it takes for the protons to realign with the magnetic field and the amount of energy released, depends on the surroundings and the chemical nature of the molecules. What Does an MRI Show? Detailed photos of soft tissues are given by an MRI. Hard bone, air, muscles, and fat appear black in the MRI images because they have different densities and water content, creating different levels of signal. Soft tissues alter in intensity from black to white from the amount of fat and water present in the tissue. Comparing the size and distributions of the bright and dark areas from the MRI image can help the radiologist figure out whether the tissue is healthy or not. The photo above demonstrates a patient with a brain tumor. MRIs are the best imaging method to use when it comes to the investigation of the brain or spinal cord. Doctors can determine what type of tumor it might be, based on how it looks on the scan and the location of the tumor in the brain using the MRI scans.
It can even measure the size of the tumor. MRIs are the best way to diagnose a brain tumor because they provide a high resolution image of the conditions from the contrast agent.To receive a clear MRI image, the patient must remain still during the process when placed inside the magnet.
MRI contrast agents are chemical substances used in MRI scans and often contains the element gadolinium which has magnetic properties that can be used to enhance certain tissues by injecting into the bloodstream. The computer have the ability to see the arteries and veins by the gadolinium absorbing in certain tissues. A computer is able to produce a black and white image from the measurement of the water content of different soft tissues. In order to increase the speed of the protons realign with the magnetic field, contrast agents may be given to the patient before or during the procedure. If the protons realign rapidly, the MRI photos will turn out brighter. Why It’s Done An MRI scan may provide more information about the problem than X-Rays, CAT scan, or ultrasound. It is probably the best method to finding tumors or examining the joints, spine, and the soft parts like the liver and kidneys.
MRI’s ability to highlight contrasts in soft tissues enables the information about the problem with joints, cartilage, ligaments, and tendons. It can be used to detect infections and inflammatory issues. MRIs can help doctors look out for symptoms of the possibility of cancer spreading to another part of the patient’s body.
MRIs are useful for imaging organs and soft tissues without radiation and showing the tissue difference between normal and abnormal. The smallest abnormalities show up on these MRI scans. Due to the fact that abnormal tissues will differ from normal, healthy tissues, the abnormal tissues will appear darker or brighter than the normal tissue on the scan.
MRI Risks The magnetic field is completely safe, but in some cases, it may cause some medical devices that contain metal to malfunction or cause problems during the exam. On the other hand, when the appropriate safety guidelines told by the technologist are followed, the examination will not harm the patient in any way. Just to be safe, the patient should tell the technologist if there are any metal or devices in their body and any health problems, surgeries they had recently and whether they may be pregnant. In other words, the patient should not wear any jewelry during the MRI procedure and may be asked to wear a gown. There may be guidelines about eating and drinking before the exam.
The patient should ask the doctor for a sedative, a drug taken for its calming or sleep-inducing effect, before the same if they have claustrophobia or anxiety. The technologist will monitor any signs to minimize the risk of excessive sedation. Those with poor kidney function may have nephrogenic systemic fibrosis, a rare but serious disease in which the exposure to gadolinium-based contrast agents used in magnetic resonance imaging that resemble thickening and darkening forming on large areas of the skin. Patients may experience an allergic reaction if the contrast material is injected into their bloodstream. However, the allergic reaction are be prevented by simply taking medicine.
Benefits There are many reasons that MRIs are the best technique than others such as X-rays, CAT/ CT scan, and etc. To assess injury or disease, X-rays passes through the body to capture one picture by using radiation. Computed tomographies are able to image bone, soft tissue, and blood vessels at once. It displays the issues with body structure and detects cancers. Unlike X-rays and computed tomography, MRI does not use radiation, making it noninvasive. Magnetic resonance imaging is more likely to detect diseases accurately than other imaging methods.
MRI are helpful in diagnosing a variety of conditions, like cancer, heart and vascular disease, and muscular and bone abnormalities. MRI enables the physicians to assess the biliary system safely without the contrast agent with gadolinium injection (this contrast material used in MRI exams are less likely to produce an allergic reaction than those that are iodine-based used for X-rays and computed tomography scanning. Applications of MRIDoctors have the ability to see how much light has been absorbed in dissimilar directions by looking through the sides. The object is divided into multiple small squares where each matches to a pixel in the image since we don’t know what’s inside. Afterwards, doctors take x-rays to solve for the attenuation coefficients of each square. The highest attenuation coefficients shows white while the lowest shows as black. Those in between show as shades of the color gray. The lighter the color, the denser the material and vice versa.
Tomography is trying to determine the internal structure. The attempt to find a tumor in one’s body is almost like finding a bottle of milk or a checker. Magnetic resonance imaging is an application of nuclear magnetic resonance (NMR), an analytical chemical technique used in laboratories all over the world to determine the content and purity of a sample. The nucleus of the atom generates a magnetic field and is a spinning charged particle. If there is no applied magnetic field, its’ spins are completely unpredictable and spins in different directions.
Yet, when there is one, the nuclei align themselves with or against the magnetic field.