Information about MRI

1. Magnetic
Resonance
Imaging (MRI)

2. History of MRI
• MRI is based on a physics phenomenon discovered in the 1930’s called
nuclear magnetic resonance (NMR), in which magnetic fields and radio
waves cause atoms to give off tiny radio signals.
• Felix Bloch and Edward Purcell discovered NMR. NMR spectroscopy was
then used as means to study the composition of chemical compounds.

3. • In 1970, Raymond Damadian discovered the basis for using magnetic
resonance imaging as a tool for medical diagnosis. He found that different
kinds of animal tissue emit response signals that vary in length, and that
cancerous tissue emits response signals that last much longer than non-
cancerous tissue.
• In 1973, Paul Lauterbur produced the first NMR image. It was of a test
tube.
• By 1977, Dr. Damadian completed construction of the first whole-body
MRI scanner, which he dubbed the "Indomitable.“

4. • Peter Mansfield improves mathematics behind MRI and develops echo-
planar technique, which allows images to be produces in seconds and later
becomes the basis for fast MR imaging
• The most significant advancement in MRIs occurred in 2003, when the
Nobel Prize was won by Paul C. Lauterbur and Peter Mansfield for their
discoveries of using MRIs as a diagnostic tool.
• Many scientist over the next years developed MRI into the technology that
we now know today.

5. Magnetic Resonance Imaging (MRI)
• Magnetic resonance imaging (MRI) is a scanning procedure that uses two
powerful magnets, radiofrequency pulses and a computer to make
detailed pictures inside the body.
• The human body is largely made of water molecules, which are comprised
of hydrogen and oxygen atoms. At the center of each atom lies an even
smaller particle called a proton, which serves as a magnet and is sensitive
to any magnetic field.

6. • Normally, the water molecules in our bodies are randomly arranged, but
upon entering an MRI scanner, the first magnet causes the body's water
molecules to align in one direction, either north or south.

7. • The second magnetic field is then turned on and off in a series of quick
pulses, causing each hydrogen atom to alter its alignment and then quickly
switch back to its original relaxed state when switched off. The magnetic
field is created by passing electricity through gradient coils, which also
cause the coils to vibrate, resulting in a knocking sound inside the scanner.

8. • Although the patient cannot feel these changes, the scanner can detect
them and, in conjunction with a computer, can create a detailed cross-
sectional image for the radiologist to interpret.

9. Different Types
of
MRI Scanners

10. High-Field MRI Scanners
-usually closed or tunnel like due to their use of stronger magnets
ranging from at least 1.5T up to 3.0T. A 1.5T MRI scanner provides a really
great quality image. The 3.0T MRI scanner becomes great for visualizing
very fine detail such the vessels of the brain or heart. There is also an ultra-
high field scanner which has a strength of 7.0T but is not widely available
and is typically used for research.

11. Low-Field MRI Scanners
-usually open MRI scanners and have a magnet range of 0.23T-0.3T.
These scanners are useful for claustrophobic or obese individuals. Low-field
scanners are typically open on the sides rather than having the magnets
completely surrounding the patient. Low-field MRI scanners have decreased
image quality and require a longer scan times compared to high-field MRI
scanners.

12. Traditional Closed MRI Scans
-a large tube where patient lays in. This type of scanner produces
images that are of the highest quality. However, the small tube that a patient
must lay in can cause claustrophobic to panic and discomfort for a heavy or
obese patient.

13. Open MRI Scans
-allow claustrophobic patients more comfort and allow obese or
larger patients to be scanned. The technology in the magnets with these
machines have come very close to matching those seen in a closed MRI.
These open MRIs still require a patient to lie down, but do not completely
enclose the patient.

14. Standing or Sitting MRI Scans
-advanced MRI machines that allow patients to stand or sit while
having their exams done. It doesn’t provide the high levels of image quality
that close or even some open scanners provide but right now they are only
useful in very specific circumstances.

15. Different Kinds
of
MRI Scans

16. • Functional MRI (fMRI)
-maps brain activity. This test looks at blood flow in your brain to see
which areas become active when you do certain tasks
• Magnetic Resonance Angiography (MRA)
-examines heart and other soft tissues and to assess blood flow
• Magnetic Resonance Venography (MRV)
-visualize blood vessels
• Cardiac MRI
-produce detailed images of heart structures
• Head MRI
-can look at problems of the brain, eyes and optic nerves, and the ears
and auditory nerves.

17. • Chest MRI
-can look at the heart, the heart valves, and coronary blood vessels. It
can show if the heart or lungs are damaged. An MRI of the chest may
also be used to look for breast or lung cancer.
• Abdomen and Pelvic MRI
-can find problems in the organs and structures in the belly, such as
the liver, gallbladder, pancreas, kidneys, and bladder.
• Spine MRI
-check the discs and nerves of the spine
• Bone and Joint MRI

18. Uses of MRI scans
• An MRI scan can be used as an extremely accurate method of disease
detection throughout the body and is most often used after the other
testing fails to provide sufficient information to confirm a patient's
diagnosis. It is a non-invasive tool that can analyze body tissues.
• Detect problems of the
Brain and Spinal Cord Heart and Blood Vessels
Bones Joints
Soft Tissues Breast
Liver Kidneys
Ovaries Pancreas

20. Preparations for a MRI
• Safety in the MRI scanner is vital. The strong magnetic fields can attract
and interfere with metal objects that you might have in or on you
(including electronic and magnetic devices). Some of these interactions
can cause harm or death.
• To ensure it is safe for you to have an MRI, you will be required to
complete a safety questionnaire.

21. • Before your MRI, let your doctor know if you:
 Have any health problems, such as kidney or liver disease
 Recently had surgery
 Have any allergies to food or medicine, or if you have asthma
 Are pregnant, or might be pregnant
 If you have tattoos. Some inks contain metal

22. • Objects in your body that can cause particular harm or be damaged
include: pacemakers, aneurysm clips, heart valve replacements,
neurostimulators, cochlear implants, metal fragments in the eye, metal
foreign bodies, magnetic dental implants, drug infusion pumps and body
piercing. Some of these implants, particularly more recent devices, might
be safe to go into the MRI scanner, but have to be accurately identified for
the scan to proceed.
• Do not wear any makeup or hairspray, as many of these products have tiny
metal particles that could interfere with the scan and reduce the quality of
the images. They might cause the area to heat up and, on the rare occasion,
burn your skin.

23. • If you are claustrophobic or you think you might not be able to proceed
with the scan, advise your doctor or the MRI facility when making your
appointment. Sedative medication can be given.
• Fasting for a MRI procedure might be required in some cases.
• Continue to take all your normal medications, unless you are otherwise
advised when you about to do the procedure.

24. Procedures during MRI
• You will usually be asked to change into a gown. Once the patient has
entered the scanning room, they will be helped onto the scanner to lie
down. Staff will ensure that they are as comfortable as possible by
providing blankets or cushions.
• Before you go into the MRI room, remove any metal jewelry, accessories,
dentures, eyeglasses, hearing aids, or wig.

25. • You will be given a buzzer to hold. When you squeeze it, an alarm sounds
in the control room and you will be able to talk to the radiographer.
• There are loud, repetitive clicking noises which occur during the test as
the scanning proceeds. Earplugs or headphones will be provided to reduce
the noise to safe levels.

26. • Depending on the type of MRI you are having and your particular
situation, at this point you might have:
 leads placed on your chest to monitor your heartbeat if having a heart
scan
 a small plastic tube (pulse oximeter) taped on your finger to check your
breathing and heart rate if having sedative medication
 a needle inserted into a vein in your arm if there’s any medication like
contrast agent or ‘dye’ called gadolinium contrast medium to improve
the appearance of a certain body tissue during the scan.

27. • The part of your body to be scanned will be carefully positioned and gently
secured. This part will then have special antennae (coils) positioned
around it to pick up signals from your body for the computer to create
images. The coils are usually encased in a plastic pad or frame. The scan
table will move into the center of the machine. Your head might be inside
or outside the scanner, depending on the part of the body being scanned.

28. • Scanning is not continuous, and each scan varies in length from about 1 to
several minutes, with a break in between. You will be able to talk to the
radiographer between each scan and can press the buzzer if you are not
comfortable or want to come out of the machine at any time.
• The scanning process is painless. You might feel warm during scanning. If
you do feel anything at all, it is important you tell the radiographer
carrying out the scan.

29. • You need to lie still and hold your position during the scan. In general, you
can breathe normally. Occasionally, during some types of MRI, you will
need to hold your breath. Breathing and movement can make the images
blurry and assessment of your problem will be more difficult.
• You might feel a twitching sensation during the test. This happens as the
MRI stimulates nerves in your body. It's normal, and nothing to worry
about.

30. After effects of an MRI
• There are no after effects of the MRI itself. You will be able to carry on your
day as planned once the test has been completed.
• If you are given any medication during the scan, you might experience
after effects. The staff looking after you will discuss any after affects with
you, and will help you if they do occur.

31. How long does an MRI take?
The scan takes about 10 to 90 minutes to complete. This depends on
the part of the body being imaged and what type of MRI is required to show
the information. Before the scan begins, the radiographer will tell you how
long the scan takes, so you know what to expect. Occasionally, you might
need to return for delayed scans, usually after 1 or 2 hours, mostly with
scanning of the liver.

32. Risks of an MRI
• There are no known side-effects of an MRI, providing you do not have any
implants or objects that must not go in the scanner.
• The danger from the MRI is due to interactions of objects with magnetic
fields. Metal objects can move, as well as get hot, and electrical currents
can be produced and lead to malfunction of a device. A strong magnet can
alter or wipe information from other magnetic devices. Some of these
interactions can cause harm or death.

33. • Metal objects that are attracted to magnets (called ferromagnetic objects),
such as buckets, chairs or objects in your pocket, can be pulled rapidly, like
a missile, into the MRI machine. These can damage the machine, as well as
injure anyone in the way
• If you are required to have an injection of gadolinium contrast medium,
there is a very small risk of an allergic reaction. Minor reactions (such as
hives or itchy eyes) can occur in approximately 1 in 1000 people. More
significant reactions (difficulty in breathing or collapse) might occur in 1
in 10,000 people. There is a small risk of an allergic reaction to any of the
medications that might be given during an MRI scan.

34. • If you have a history of kidney disease, you should have a blood test before
the scan to ensure that the contrast medium can be given safely.
Nephrogenic systemic fibrosis is a rare, but serious complication following
a gadolinium chelate injection in people with very poor kidney function.

35. Benefits of MRI
• MRI does not use radiation. Avoiding the need for exposure to ionizing
radiation (X-rays) is of significant benefit to younger people and children.
MRI can also be used safely in pregnancy, if required.
• MRI is capable of providing your doctor with a wide range of information
about your body and particular diseases or conditions you might have. It
can show certain conditions that other tests can’t show. MRI can image
most parts of the body in any direction to obtain maximum information
and provides this information in high-quality images. These images give
accurate details about certain processes or structures within the body and
can also provide information as data or graphs.

36. Who does MRI?
A radiographer (medical imaging technologist), who is specially
trained in MRI, is responsible for looking after you in the hospital
department or private radiology practice, and for taking the scans. The
scans are then passed to a radiologist (a specialist doctor), who interprets
these and provides a written report to the doctor who referred you for the
scan.

37. Where is a MRI done?
Most private and public hospitals, and private radiology practices
have MRI scanners. You can contact your local hospital, radiology practice or
your referring doctor for a list of places that have an MRI scanner.

38. How much does it cost?
The price varies depending on the affected body part that will be
scanned and the hospital or clinic. But the price ranges from P7,000-
P25,000.

39. References
• https://two-views.com/mri-imaging/types.html
• https://stanfordhealthcare.org/medical-tests/m/mri/types/fmri.html
• https://www.radiologyinfo.org/en/info.cfm?pg=bodymr
• https://www.webmd.com/a-to-z-guides/what-is-an-mri
• https://medlineplus.gov/mriscans.html
• https://www.medicalnewstoday.com/articles/146309.php
• https://www.medicinenet.com/mri_scan/article.htm#
• https://www.insideradiology.com.au/mri/
• https://www.thoughtco.com/magnetic-resonance-imaging-mri-1992133
• http://web2.uwindsor.ca/courses/physics/high_schools/2006/Medical_Imaging/mr
ihistory.html
• https://two-views.com/mri-imaging/history.html

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