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MRI

MRI stands for magnetic resonance imaging. It is a particularly useful scan for neurology, cardiology and oncology patients. Questions on how they work, their development and uses can go in this category.

800 Questions

Any suggestions on how to get through an MRI when you're clostraphobic?

Ive had a MRI and iam claustrophobic and it was not all that bad if its on your foot then that's best.

What are similarities between MRI and CAT scans?

Other than the fact that it creates an image of your body for medical purposes...absolutely nothing.

Xray uses ionizing radiation (the potentially harmful kind) which passes through your body. Some of it comes out the other side and reacts with a detector that is behind your body. This creates an image by reflecting how much of the radiation passes through. This is dependent upon what type of tissue it is passing through. Bone, for example, will not allow as much to pass through as soft tissue such as fat or muscle.

MRI is very different and quite complicated. It creates images by measuring the way hydrogen molecules in your body react to a magnet. One of the magnets is switched on and off rapidly and the reactions of the hydrogen molecules will depend upon what type of tissue is there. Hydrogen molecules in fat, for example, are attracted to the magnet very quickly, while hydrogen in water will move more slowly. This is the concept used to get images. It does not use the harmful type of radiation like Xray.

Can you have an MRI of neck with screws and plate in ankle?

Depends on the type of mental the screw is made of, some metals are MRI safe whilst older ones are not. Details of this will be in your medical records (the operation report) at the hospital where you had the screw put in your knee. Some people are given a piece of paper to carry after an operation where metal is placed in them detailing exactly what was used if you have one of these show it to the doctor treating your knee.

Can you have an MRI if you have metals in your body?

The attendant will ask about what you have in your body--piercings, hip replacements, medicine patches with metal backing--and then will tell you what you have to do. They do not want the metal to shift during the scan.

How often can an MRI be performed on the same person safely?

MRI uses high magnetic fields and radio frequency and not x-ray. The procedure is generally safe and typically repeated examinations do not cause any problems.

However, some MRI scans use a Gadolinium-based contrast agent, so repeating MRI scans within a few days may expose a patient to higher-than-expected levels of the contrast agent in the blood, which can be affected by kidney function. Patients should check with their doctor before having a repeat contrast MRI scan within a few days.

How MRI works?

As the patient enters an MRI scanner a large magnet surrounds the patient. The scanner subjects nuclei of the body's atoms to a radio signal, temporarily knocking select ones out of alignment. When the signal stops, the nuclei return to the aligned position, releasing their own faint radio frequencies, which are sent to a computer to build up detailed images of the patient's anatomy.

What does an MRI scan do?

An MRI machine uses radio waves and a very, very strong magnetic field to take pictures of the soft body tissues. The radio waves and magnet align the spin of protons and these allow images to be taken.

How does MRI use electromagnets?

  • An MRI uses electromagnets to produce an super strong magnetic field. This field causes changes in the behavior of cells and when the magnet is off those cells emit a detectable wave that is picked up by sensors. A computer then interprets those signals and creates a picture of the tissue. The picture is then looked at by specialists to find things that are not normal compared to surrounding tissue.

What does essentially normal mean?

Normal is a hard thing to define. If the "normal" height for a woman is 66 inches, is a woman of 64 inches abnormal? No, she's "essentially normal." While it's not a very descriptive phrase, essentially normal means that it's within the range of normal human anatomy/physiology.

Are you free to approach an MRI machine if it has been turned off?

Yes, and even when MRI machines are in use, they are very safe if proper procedures are employed.

What advantage does the MRI scan have over the Pet scan for the subject?

A PET scan shows what level / stage (if any) the cancer is at. An MRI scan doesn't do this, the reader, looks for abnormalities on the scan which shows up everything in the body.

Do you have to fast before an MRI?

Eating Before Having An MRIFor certain kinds of MRI scan (e.g. an MRCP which looks at the biliary system) it's very important that you don't eat or drink for 4-6 hours before the scan. If you're having a scan of your pelvis it's often best not to eat beforehand so that artefact from bowel motion is reduced. The radiographers or technologists at the MRI Unit will advise you on the specific requirements for your scan though.

Is MRI safe with titanium dental implants in jaw?

Yes, it is generally safe to have an MRI (Magnetic Resonance Imaging) if you have titanium dental implants. Titanium is a non-magnetic material that is commonly used for dental implants precisely because it is compatible with medical imaging techniques like MRI.

Titanium is not affected by the magnetic field of an MRI machine, so it does not pose a risk of movement or displacement during the imaging process. However, it's always important to inform the MRI technician or radiologist about any implants or metal objects in your body before undergoing an MRI. They can provide specific instructions and ensure that appropriate precautions are taken to ensure your safety and the quality of the imaging.

In some cases, the presence of dental implants may cause artifacts on the MRI images, which can make it slightly more challenging to interpret the results. However, modern MRI machines are equipped with advanced imaging techniques that can minimize or compensate for these artifacts, allowing for a clear visualization of the area of interest.

It's worth noting that if you have any other metal implants or devices in your body, such as certain types of joint replacements or pacemakers, there may be additional considerations or precautions to take before undergoing an MRI. Therefore, it's crucial to provide a comprehensive list of any implants, devices, or metal objects to the medical staff prior to the MRI.

In summary, having titanium dental implants should not prevent you from safely undergoing an MRI. However, it's important to inform the MRI technician about your dental implants and any other metal objects in your body to ensure appropriate safety measures are taken and to obtain the most accurate imaging results.

How are MRI images formed?

The magnetic and radio wave bursts stimulate signals from hydrogen atoms in the patient's tissues that, when subjected to computer analysis, create a cross-sectional image of internal structures and organs

Can you have MRI scan with titanium implant?

No, Titanium is not magnetic so the MRI won't bother the implants. The implants don't show up very well on the scans either but they will on an x-ray. My wife had brain surgery and they used a titaniun plate to cover the hole in her head and she gets required MRI scans of her head.

Are picc lines safe for an mri exam?

There are no indications whether a picc line is safe with a MRI. I would not see any reason why not.