Magnetic Resonance Imaging (MRI) scan is a painless medical imaging technique that uses strong magnetic fields and radio waves to generate detailed images of the internal structures of the human body. Unlike Positron Emission Tomography (PET) scans and Computed Tomography (CT) scans, MRI does not involve radiation, providing patients with a relatively safe examination method.

MRI scans are typically performed by laboratory technicians. After completion, radiologists, who are doctors specialized in medical imaging, interpret the results and send a report to the referring healthcare provider who arranged the scan for the patient.

MRI can produce clear images of soft tissues, such as the brain, muscles, and ligaments. Moreover, it is excellent at distinguishing between diseased and normal tissues, enabling healthcare providers to diagnose and monitor various medical conditions. It can also be used to monitor the fetus in pregnant women.

Healthcare providers often use MRI to evaluate the condition of organs, blood vessels, or lymph nodes, and to diagnose and monitor diseases such as abdominal or pelvic tumors, intestinal inflammation caused by diseases like appendicitis (inflammation of the appendix) or Crohn's disease (an inflammatory bowel disease [IBD] that causes inflammation in the gastrointestinal tract), liver diseases such as cirrhosis (a disease that causes severe scarring and damage to the liver) or biliary tract abnormalities (the ducts connecting the digestive organs), and vasculitis, a disease in which the body's immune system attacks blood vessels.

In addition, MRI is of great significance for examining the brain and spinal cord. For example, it can distinguish between white matter (WM) and gray matter (GM) in the brain. GM consists of cells that contribute to functions such as cognition and movement, while WM is composed of nerve fibers that help GM regions communicate. Some diseases affect one substance more than the other. For instance, people with Parkinson's disease (PD) and Alzheimer's disease (AD) have less gray matter. MRI can also detect aneurysms and tumors.

Meanwhile, for pregnant women with symptoms or test results that require further examination before childbirth, MRI scan is a safe option as it does not involve exposure to ionizing radiation, which can be harmful to the developing fetus.

Common MRI scan sites include the skull (head), cervical spine (the part of the spine in the neck), chest, heart, abdomen, lumbar spine (the lower part of the spine), and pelvis (the area between the hip bones).

Magnetic Resonance Angiography (MRA) is used to examine blood vessels, and Magnetic Resonance Venography (MRV) is used to examine veins.

Functional Magnetic Resonance Imaging (fMRI) can evaluate how much blood flows to the brain when performing certain tasks. fMRI scans allow healthcare providers to determine which areas of the brain are most active and whether there is brain damage.

MRI machines resemble CT or PET scan machines, with a large machine and a circular hole in the middle where patients lie during the examination. There are also open - type MRI machines with open sides. In most MRI machines, an electric current passes through the coils in the machine. Coils may also be placed around the body part being examined. The coils generate a magnetic field. They send and receive radio waves through the coils to produce signals, which then generate images.

The core principle is to use a high - power magnet to temporarily change the direction of hydrogen atoms in the body. When hydrogen atoms return to their original positions or realign, they generate energy. Different types of body tissues produce different amounts of energy, and the time required for hydrogen atoms to realign also varies depending on the tissue type. This helps medical staff distinguish between different types of tissues, such as bones and muscles. Some MRI examinations use a special dye called a contrast agent, which is usually injected into a vein (intravenous injection, IV) to make the images clearer.

The healthcare provider needs to confirm whether MRI is safe for the patient. If the patient has an implanted device, such as a pacemaker (a device that controls the heartbeat), they should inform the person arranging the MRI scan and bring the device's brochure on the day of the scan.

The patient needs to fill out a questionnaire to inform about potential risk factors such as pregnancy. Since the impact of fetal exposure to the contrast agent is unclear, the contrast agent is usually not used during pregnancy.

If the patient has claustrophobia or an extreme fear of confined spaces, they can choose an open - type MRI machine or take a mild sedative. At the same time, the patient should inform the technician about the presence of foreign objects in the body, such as residual bullets or shrapnel, as well as any jewelry, hearing aids, removable dental accessories, or body piercings.

Upon arrival at the examination site, the patient needs to remove all metal or electronic items, including mobile phones, electronic watches, glasses, and hairpins. The MRI magnet is very powerful and may attract these items, causing harm to the patient or the MRI technician. Also, certain types of metal can blur the images. The duration of an MRI scan varies depending on what is being scanned, usually ranging from 20 to 90 minutes.

During the MRI scan, the patient lies on a movable examination table. The technician may place small coils around the body part being examined to obtain clearer images. If the test includes a contrast agent, the service provider will connect an intravenous tube to the patient's hand or arm.

When the test starts, the table is moved into the machine. The patient will hear loud thumping and clicking noises. The MRI scanner can be very noisy, so the technician usually provides earplugs or headphones for the patient to wear during the scan. If the examination involves a contrast agent, after several initial scans, the patient will receive the contrast agent through the intravenous tube. It is normal to feel a warm sensation in the mouth or have an unusual taste. After the injection, the technician may ask the patient to hold their breath for a few seconds to obtain clear images. Although the MRI examination is not a painful process, the patient needs to remain still during the examination. The patient may feel anxious, especially if they dislike loud noises or small spaces. They may also feel a warm sensation in the imaging area, which is normal. The technician may sit in an adjacent room with a window so that they can see the patient. Most MRI machines are equipped with an intercom, allowing communication between the patient and the technician throughout the process. If the patient needs immediate attention, they may also have a "squeeze ball."

If no sedative was used during the MRI scan, the patient can usually leave and resume all daily activities immediately after the scan. If sedative medication was taken, the patient will need someone to drive them home. Also, due to the sedative effect, the patient may be advised not to do certain things, such as operating heavy machinery, for a short period after the MRI scan.

MRI is safe for most people. However, there are some potential risks. For example, some people may have an allergic reaction to the contrast agent. The symptoms are usually mild and can resolve on their own. Nephrogenic systemic fibrosis is a very rare but serious complication that may be associated with contrast agents containing gadolinium. The healthcare provider will assess the patient's kidney function before the MRI examination because this is usually a complication in patients with severe kidney failure who require dialysis. More research is needed to determine if there is a causal relationship.

Patients with certain implanted devices should avoid MRI examinations. The magnetic field may affect some implanted medical devices or pose potential risks. These implants include capsule endoscopy capsules (pills taken before endoscopy, a procedure that uses a miniature camera to take images of the digestive tract), cochlear implants (devices that improve hearing), insulin pumps (devices that deliver the hormone insulin through a catheter, a small tube placed in the body), loop recorders (devices that record heart activity), old - fashioned pacemakers containing iron (devices that help control the heartbeat), and vagus nerve stimulators (devices that stimulate the vagus nerve, which helps regulate heart rate, digestion, and blood pressure).

Although MRI is safe for children, very young children often have difficulty staying still or holding their breath to complete the examination. Therefore, they may need sedatives or anesthetics. Pregnant women can also undergo MRI examinations. However, for extra caution, the healthcare provider may recommend waiting until after the first trimester of pregnancy to have an MRI scan.

Generally, there is no need to adjust the diet before the scan, and the patient can usually take medications as prescribed, unless the healthcare provider instructs otherwise.

The patient should prepare comfortable clothes that are easy to take off and put on. They may be required to change into a gown for the examination. Bring identification and medical cards, such as insurance cards, to present before the procedure. If there is a metal implant, bring a card indicating its MRI compatibility. Also, bring the order form provided by the healthcare provider, which describes the imaging examination being performed. They may also send the order in advance. The patient can bring an accompanying person. Inquire whether this is allowed when making the appointment. If the patient receives intravenous sedation, someone must drive them.

The patient may have questions about the cost of the MRI examination and whether their insurance covers it. If the MRI scan is medically necessary, the insurance company may cover part of the cost. Contact the insurance company before the examination to find out what costs are covered and if there are any payment plan options.

After the MRI scan, the radiologist examines the images for any abnormalities or changes compared to previous scans (if any). Then, the radiologist sends a report to the referring healthcare provider. The report usually includes the following information: the type of examination (MRI), the reason for the examination, a comparison with previous imaging examinations (if applicable), the technique, including whether the examination included contrast, the findings, including normal or abnormal results, and the impression, including the most important findings and possible causes.

The time required to receive this report depends on whether there are any immediate findings that may be life - threatening or require quick treatment decisions. The patient will most likely be able to view the report in the electronic health record system. They may also receive the MRI results at their next visit. If the MRI results are inconclusive, the healthcare provider may recommend other examinations, such as other imaging or blood tests, to assist in making a diagnosis.

In conclusion, as an important medical imaging technique, MRI scans play a crucial role in disease diagnosis and monitoring. Before undergoing an examination, patients should communicate fully with their healthcare providers to understand the examination procedures and precautions to ensure the smooth progress of the examination.