MRI (Magnetic Resonance Imaging) Muscle, tendons, nerves, brain. Some Pros: Creates an excellent picture, no radiation exposure. Some Cons: Takes a longer time (e.g. up to 40 mins), expensive, may not be accessible to people in the country.
MRI provides better soft tissue contrast than CT and can differentiate better between fat, water, muscle, and other soft tissue than CT (CT is usually better at imaging bones). These images provide information to physicians and can be useful in diagnosing a wide variety of diseases and conditions.
An MRI scan can produce more detailed images of tissues and organs than a CT scan. An MRI scan may be used to diagnose issues with soft tissue, joints, organs, the brain and the heart. MRI scans are more expensive than CT scans as the equipment is more costly and the process takes longer.
CT scans are far quieter and do not cause hearing problems compared with MRIs. CT scans are also preferable among those who are claustrophobic or anxious because the machine is more open and the X-ray device circles around the patient. The main disadvantage to having a CT scan is that it exposes your body to radiation.
The exact time required depends on whether you need a contrast dye for the procedure, but MRIs always require more time for the scan. A typical CT scan lasts 10 minutes whereas MRIs can take up to an hour or longer.
Generally, CT scans are better at spatial resolution, while MRIs are better at contrast resolution.
MRI contrast may also have an effect on other conditions such as allergies, asthma, anemia, hypotension (low blood pressure), and sickle cell disease. There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.
Unlike X-rays and CT scans, MRIs don't use any radiation. At Johns Hopkins, we've developed very fast, high-resolution MRIs that can be done in 10 minutes or less. An MRI scanner is a highly specialized machine and may not be available in some imaging facilities or emergency rooms at other hospitals.
A whole body MRI screening can help detect possible cancer lesions, aneurysms (blood vessel blockages), bone and joint issues, and spine problems inside your body. An MRI scan of the head and a spine MRI may help detect: Brain injuries. Blood vessel damage.
Sometimes the contrast agent can cause side effects, such as: feeling or being sick. a skin rash. a headache.
MRI scanners are particularly well suited to image the non-bony parts or soft tissues of the body. They differ from computed tomography (CT), in that they do not use the damaging ionizing radiation of x-rays.
MRIs are more versatile, and doctors use them for examining many medical conditions. For example, x-rays are used more for examining broken bones, but they can also help detect diseased tissue. MRIs are better for evaluating soft tissues such as tendon and ligament injuries, brain tumors or spinal cord injuries.
An MRI machine uses powerful magnets that can attract any metal in your body. If this happens, you could get hurt. It can also damage equipment that's implanted in your body -- a pacemaker or cochlear implant, for instance. Also, metal can reduce the quality of the MRI image.
Concerns about CT scans include the risks from exposure to ionizing radiation and possible reactions to the intravenous contrast agent, or dye, which may be used to improve visualization. The exposure to ionizing radiation may cause a small increase in a person's lifetime risk of developing cancer.
An MRI does not use radiation, and a CT Scan does not use a magnet. Meaning, one is safer than the other for some patients. Anyone with metal in their body (pacemaker, stent, implant etc.) need to ensure the material is MRI safe, for those sensitive to radiation, a CT scan is not a good option.
Many studies have concluded that MRI is one of the safest technologies for imaging the body. The examination causes no pain, and the magnetic field produces no known tissue damage of any kind. When proper safety guidelines are followed, people of all ages can undergo an exam.
Since the MRI machines are magnets, it is best to not apply deodorants, antiperspirants, perfumes, or body lotions before the examination. These items contain metals that might interfere with the magnetic field inside the MRI machine and cause you to have distorted images and wrong results.
How long is my MRI exam? The length of your exam will depend on what is ordered by your doctor, or the body part of interest. In general exams will take 45-60 minutes and up to 2 hours for specialty exams. On average, brain and spine exams may last about 45 minutes.
Allergy-like reactions
It usually settles down by itself within an hour or so, but rarely it might be a warning sign of a more serious allergic reaction developing. Severe allergic (anaphylactic) reactions to gadolinium contrast medium have occurred, but are extremely rare.
There aren't any side-effects from the MRI scan itself. However, if you've had an injection of contrast medium (dye) as part of the investigation, you may have some side-effects which might include a skin rash, dizziness, a headache, and nausea.
The EAONO proposal is that after the initial diagnosis by MRI, a first new MRI would take place after 6 months, annually for 5 years, and then every other year for 4 years, followed by a lifelong MRI follow-up every 5 years.
Where MRI really excels is showing certain diseases that a CT scan cannot detect. Some cancers, such as prostate cancer, uterine cancer, and certain liver cancers, are pretty much invisible or very hard to detect on a CT scan. Metastases to the bone and brain also show up better on an MRI.
MRI is very good at zeroing in on some kinds of cancers. By looking at your body with MRI, doctors may be able to see if a tumor is benign or cancerous.
An MRI can also detect old strokes for decades after they happen. The fastest type of MRI is diffusion-weighted imaging (DWI). It measures shifts in fluid in the brain and can detect a stroke soon after its onset. An MRI can also detect evidence of past strokes.