MRIs and MRAs pose extremely little health hazards. Out of the millions of MRI scans conducted each year, the FDA gets around 300 reports. This is compared to the thousands of cases of leukemia, cancer of the brain, and other severe diseases that result from exposure to magnetic fields in other areas of the environment. The only significant hazard associated with an MRI scan is if you are a patient or staff member who can be exposed to excessive radiofrequency (RF) radiation.
An MRI scanner uses strong magnets and a pulse of radiofieid to create detailed images of your body. The image results from variations in the strength of hydrogen atoms in different parts of your body. These variations in turn result from differences in the chemical composition of these parts. The pulse of RF radiation used by the scanner to detect these variations causes no harm to living tissue.
However, it has been suggested that repeated exposures to high levels of RF radiation may cause cancer. There is some evidence that individuals who receive many MRI scans are at increased risk of developing tumors elsewhere in their bodies. However, there is also evidence that this risk decreases over time as people age. It is not known whether a similar risk applies to people who are already diagnosed with cancer.
Every year, millions of MRI scans are done in the United States, and the FDA receives around 300 adverse event reports for MRI scanners and coils from manufacturers, distributors, user facilities, and patients. The vast majority of these complaints mention warmth and/or burns (thermal injuries). However, a small but significant number of complaints involve fractures or other serious injuries caused by loose parts inside the MRI scanner.
About 30,000 people per year receive an implantable cardiac device such as a pacemaker or defibrillator. These devices can be damaged by high magnetic fields such as those used in MRI examinations. Patients with implanted cardiac devices should tell their physicians about any plans to have an MRI examination.
MRI scans are useful in diagnosing diseases and anomalies of the brain and spinal cord. They are also helpful in monitoring treatment responses and preventing recurrence. In addition, they provide valuable information on muscular conditions and organ systems outside of the brain and spine. MRI scans are particularly useful when X-rays cannot be applied because of the risk of radiation damage or if multiple views are needed to make a complete picture of an injury or condition.
The safety of MRI scanning has been established through numerous studies. Individuals who undergo MRI scans are usually given special instructions to avoid certain behaviors that could affect the test results. These include not drinking alcohol or taking medications that contain caffeine or acetazolamide (Diamox), which can cause dehydration.
While there are few hazards associated with MRI as it is to be conducted, and MRI scanning is pleasant, participation may cause some discomfort. The most common problem is hearing loss, which may occur due to noise produced by the magnets. Other problems include feeling faint when lying in the supine position for long periods of time, having your skin tingle or feel warm, and having heartburn or indigestion.
There are two types of magnetic resonance imaging (MRI): whole-body and local. Whole-body MRI uses strong magnets to create detailed images of the body's organs and tissues without cutting them out of their natural setting. This type of scan is used to diagnose disease or trauma such as cancer or stroke. Local MRI uses a magnet that is strong enough to detect individual organs and tissues within the body. It is used to look at the brain, spine, chest, abdomen, and pelvis. There are also diagnostic scans called MR angiograms and functional MRI studies that show brain activity during cognitive tasks or while patients watch moving pictures. These tests are useful in diagnosing diseases such as vascular dementia, multiple sclerosis, and brain tumors.
Whole-body MRI requires you to wear a gown to protect you from any metal in your body.
MRI equipment allow physicians to look inside your body and detect what's wrong, but errors may injure or even kill you. According to Tobias Gilk, an MRI safety advocate, if performed properly, it is one of the safest tests ever devised. Accidents do, however, occur. In this article we'll review the most common dangers associated with MRI exams and suggest ways to avoid them.
The main danger from modern MRI scanners is actually not from the machine itself but rather from human error. While many people are concerned about being hit by a moving magnet, the real danger comes from procedures that users may not follow correctly or might try to cheat by using tools or substances that can damage the scanner or harm them if they are exposed to intense magnetic fields.
Some examples of user errors that can lead to accidents include:
Not wearing a set of headphones when in a strong magnetic field. The sound of voices or music inside the scanner can attract metal objects inside the body such as rings or jewelry. These objects can be driven into vital organs such as the brain or heart causing serious injury or death.
Taking pills or eating products that contain metals. Any substance that contains iron or copper, such as blood, will become magnetized during an MRI scan.
According to the Food and Drug Administration, the increased risk of any one individual having a deadly cancer as a result of a standard CT scan is roughly one in 2,000. Because MRIs do not employ ionizing radiation, there is no chance of cancer being increased. However, they take substantially longer to complete than CT scans. So if you have multiple images taken over time, then you are absorbing more radiation over time.
The most effective way to minimize your exposure to radiation is through careful choice of imaging tests. For example, instead of using CT for full body scans, clinicians may choose to use magnetic resonance imaging (MRI) because it is more sensitive to soft tissue abnormalities. Also, patients who are considered at high risk for developing cancer can have periodic scans with radiopharmaceuticals that are administered into certain tissues or organs. These scans are called positron emission tomography (PET) scans.
An average chest x-ray has a dose level of about 0.5 mSv. An average mammogram has a dose level of about 10 mSv. An average head CT scan has a dose level of about 5 mSv. An average abdominal CT scan has a dose level of about 15 mSv. An average pelvic CT scan has a dose level of about 20 mSv.
An average MRI has a dose level of about 1 mSv. A PET scan has a dose level of about 5 mSv.