MRI Scan: Purpose, Procedure & Types [Guide]
Very often we thank the God for the moral support and doctors for treating diseases successfully but how often we thank the inventor of the technology. Researchers and the scientists are putting continuous and consistent efforts in the medical field. With the advancements and innovations, it is now possible to detect the diseases in early stages and get treatment on time. MRI scan is one such advancement and innovation in the medical science. MRI Scan is an invention of the first half of the 20th Century.
What is the meaning of MRI scan?
MRI Scan Full Form is Magnetic resonance imaging (MRI). It is more popular as MRI scan. MRI scanning is a revolution in the medical science as it can scan and produce detailed images of tissues, organs and other structures inside the body. It makes use of strong magnetic fields and radio waves to produce images.
Did you know?
Sir Peter Mansfield and Paul Lauterbur were awarded Nobel Prize in 2003 for MRI. however Raymond VahanDamadian, an American physician was the first one to put MR imaging into practice. He nicknamed his first MR (Magnetic Resonance) Scanning machine, the “Indomitable”.
The first human scan was done by Raymond VahanDamadian on July 3, 1977 using the principle of nuclear magnetic resonance to diagnose cancer.
What is the Purpose of MRI Scan?
A brief answer would be that MRI scan is used to analyze almost any part of the body especially to detect:
- Brain tumors and any related abnormalities
- Problems related to the spinal cord, joint or muscles
- Breasts or other forms of cancer
- Problems related to heart and blood vessels
- Problems related to internal organs, such as the liver or prostate gland
- Abdominal tumors or Cancer
MRI Scan Vs CT Scan: Differences & Applications
Are they same, Absolutely “NO”, unlike CT scan there are no X-rays or any radiation involved in MRI scan? To add to the advantage, MRI scans are more detailed. They are capable to describe all soft tissues and higher density tissues, such as bone. To summarize, MRI scan is preferred over a CT scan for:
- Imaging joints, the brain, and the spinal cord, where the finer detail of soft tissues are needed.
- To identify tumors.
- To find areas of inflammation and infection.
- Those patients who are not able to have a CT scan such as pregnant ladies, patients with metallic fragments, surgical clips, cardiac pacemakers etc.
- The fact that without asking the patient to move, relatively more images in any plane can be produced.
If ignored that MRI scan is costlier and takes longer over CT scans, for all the above reasons MRI scan is proven to be better than CT scan. However, CT Scan is preferable for fracture detection, Stones & some specific cases related to abdominal tumors.
What are the various MRI Techniques?
An MRI scan may need special techniques as described below to get additional information which can be further studied by your physician.
- Dynamic Contrast – This technique makes use of the gadolinium-based contrast agent to get the better quality images. It can give detailing about tumor blood flow. The word “Dynamic” implies that gadolinium-based contrast agent causes the relaxation time of nuclei within body tissues to decrease over the conventional contrast agents. Images obtained from gadolinium injection have a higher signal than normal contrast agents.
- Diffusion MRI- It can give the detailing of the inflammation within tissues based on the microscopic movement of water molecules in the tissue. This technique is primarily used with brain pathology.
- Magnetic Resonance Angiography (MRA)-With help of a contrast, a strong magnetic field, and radio wave energy, this technique is used to make the blood vessels to appear more clearly on the image.
- Magnetic Resonance Spectroscopy (MRS)– This technique is used to identify the size and stage based on the chemical activity within cells of a tumor.
- Perfusion MRI–This technique is used to show the blood flow within the capillaries in tissues. It also gives the detail of both amounts of blood flow within the capillaries and the time involved. This technique is helpful in detecting brain-related problems for example stroke and tumors but is also helpful in areas where blood flow is crucial. Perfusion MRI is also common for breast MRI scan.
How does MRI scan work?
You may recall what you have read in your high school about the human body and little chemistry about the atom. Atom is subdivided into neutrons, protons, and electrons. MRI scan technology makes use of the physics involved with protons. As you know the human body is made up of water molecules which consist of hydrogen and oxygen atoms. Protons in hydrogen atom behave like small magnets and are very sensitive to magnetic fields. So when you lie under the powerful magnets of MRI scanner, the protons in your body line up in the same direction.
When the radio waves are sent to certain areas of the body the protons lose out alignment and realign when the radio waves are turned off. Radio signals sent by the protons in this process are then picked up by the receivers. These signals not only carry the information about the exact location of the protons in the body but also help to differentiate between the various types of tissue in the body. The fact is that protons in different tissues realign at different speeds and sends distinct signals which makes them unique and identifiable.
A computer plays a vital role in displaying those signals on the screen in the form of pixels as the signals sent by numerous protons in the body are combined to create a detailed image.
3.0 Tesla (T) Vs 1.5 Tesla (T) MRI, Which One is better?
MRI scan is magnetic resonance imaging scan and Tesla (T) is the standard unit to measure magnetic flux density. As the number signifies, the magnetic field of 3.0 T MRI scanner is twice of the magnetic field generated by a 1.5 T MRI scanner. Though 1.5 T machines are standard but 3.0 T Machines are gaining market over 1.5 T MRI scanner due to:
- Its ability to minimize or eliminate noise present in an MRI scan images. Generally, the patient’s body and the electronics inherent to the MRI system are sources of the noise. Both 3.0 T and 1.5 T MRI scanners reduce the noise but the choice remains to what extent we need the noise-free quality images. For more elaborated results it’s advisable to go with 3.0 T MRI machine.
- Better image clarity with respect to scan time.
It is not that 1.5 T MRI machines are not accurate, only that when compared to 3.0 T MRI scanner; noise in the signal will be more and time taken for scanning will be more. So if you know that a less detailed study is to be carried out or if you can afford slower pace; 1.5 T MRI machine equipped with multi-channel coils is adequate. On the contrary for a detailed study, high volume of patients and for getting better images in a shorter time; 3.0 T MRI machine is what you should go with.
What is MRI Brain Scan?
Main Article: MRI Brain
Magnetic resonance imaging (MRI) of the brain also known as cranial MRI. It gives out information of your brain and brain stem. An MRI Brain is required to detect various brain conditions such as:
- tumours
- spinal cord injuries
- Building up of spinal fluid in the brain cavities
- stroke
- infections
- hemorrhage or bleeding
- inflammation
- blood vessel issues
What is an MRI scan Knee?
MRI Knee is the magnetic resonance imaging (MRI) of the knee and its surrounding areas. The knee MRI scans give details about the soft tissues in your body along with the bones so that the injured knee or any abnormalities could be studied. The MRI scan Knee also gives information of other sections of the knee such as bones, cartilage, tendons, muscles, blood vessels and ligaments. It helps determine the possible causes of the pain, inflammation or weakness in the knee. It enables the doctors to determine and diagnose:
- bone fractures
- tumors
- building up of fluid in the knee
- knee joint problems
- infection
- arthritis
- damaged cartilage, ligaments, tendons
What is MRI Scan Spine or Lumbar MRI scan?
Magnetic Resonance Imaging (MRI scan) of the spine or Lumbar MRI is to study normal and abnormal spinal structures. It helps to diagnose back pain. The MRI spine helps physicians to study a patient’s spinal anatomy and to determine an anatomical cause of the patient’s back pain. In layman’s terms, the lumbar MRI is related to the lumbar section of your spine where back problems commonly occur.
The lumbosacral spine consists of the five lumbar vertebral bones, the sacrum, the tailbone, blood vessels, nerves, tendons, ligaments and cartilage. Lumbar MRI enables physician or doctor to diagnose problems related to the spine such as:
- persistent or severe lower back pain
- back pain along with fever
- Birth defects affecting your spine
- injury to your lower spine
- signs of brain or spinal cancer
What preparation is required for MRI scan?
To-Do Things Before the scan
Fill The Form:
At the hospital, prior to the MRI scan, you’ll be asked to fill in a questionnaire about your health and medical history. Fill the form carefully as it will help the medical staff to carry out the scanning safely and properly. Read more about To Do Things Before the Scan and common FAQs regarding MRI scan. Once you are done with the questionnaire, you need to give your signed consent for the scan to go ahead. Not to worry it’s a routine work.
Do Not Forget to Tell your Doc:
As the MRI is based on magnetic and radio waves, it is important to inform your physician or doctor prior to test if you
- Are allergic to any in particular or have blood clotting problems.
- Are going through pregnancy.
- Have metal pieces in your body such as metal artificial joints, plate, screw or rods to address bone fractures etc.
- Have electronic devices such as a cardiac pacemaker in your body.
- Tattoo on our body. Some inks contain metal.
If you’re not sure about any metal fragments in your body, an X-ray may be advised.
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Remove the following and lock them safely
As the MRI scanner generates strong magnetic fields, all the metal objects must be removed from the body before scanning, including:
- watches
- jewellery, such as earrings and necklaces
- braces
- hearing aids
It is better to leave the valuables at home otherwise also can be stored in a secure locker or handed over to your escort as the last option.
What is done during MRI Scan?
An MRI scanner is a tubular structure open at both ends with strong magnets. A motorized bed moves inside and out of the tunnel or the scanner. Depending on the part of the body being scanned, lying on the motorized bed you enter the scanner either with head first or feet first. Sometimes during the scan, a frame with receivers may be placed over the body part being scanned such as the head or chest to pick up the signals emitted by the body to create an image of better quality.
MRI scanner is operated by a radiologist through a computer kept in the adjacent room so that it is safe from the magnetic field created by the scanner. Need not panic because when you are inside the scanner, you are being continuously monitored through the television monitor. If required you will be injected with the contrast dye through an IV needle placed in your arm and will be removed once scanning is done and before you leave for home.
While you are undergoing scanning, the person escorting you may be allowed to stay in the room unless they also follow the same guidelines regarding clothing and removing metallic objects.
Do remember that you should stay still throughout the scan to avoid the images being blurred until the radiologist asks you to relax. Depending on the area of concern and the number of images required, the scanning may take 20 to 60 minutes.
The MRI scanner does make a lot of noise so you’ll be given earplugs or headphones to wear. The noise is due to the fact that the electric current in the scanner coils is turned on and off to generate magnetic waves.
What after the scan?
An MRI scan is an outpatient procedure so you will not be asked to stay back in the hospital so once the scanning is done you can get along with your daily chores. However, if you are anaesthetized with a sedative you may need an escort to drive you home safely.
A radiologist will study your MRI scan and will prepare a detailed report which will be later studied by the consultant or physician who prescribed you the MRI scan in the first instance.
Common FAQs Regarding MRI
Am I allowed to Eat or Drink before an MRI scan?
In general, before MRI scanning, you are allowed to eat, drink or take any medication unless otherwise advised by your physician or radiologist. Depending upon case to case and area to be scanned, sometimes patients are asked not to eat or drink anything for up to three-four hours before the scan and sometimes are asked to drink plenty of water before MRI scanning.
How long will the Scanning take?
Well, it depends upon the criticality of the case and which part to be analyzed and the number of images required.Usually, MRI scanning may take 20-60 minutes. For suppose, if the images from the first scan are not good enough then radiologist may straight away ask the patient to undergo second scanning.
Does it affect if I have braces/filings?
As MRI is magnetic wave-based technology, a metal may hamper or blur the images; however, it is better to consult the doctor and radiologist beforehand. It Should not be a problem.
Am I allowed to move inside MRI Scanner?
Well, it’s a Big “NO”. Stay still while you are in MRI tunnel or else your movements will hamper the scanner. It may blur the images.
What if I am claustrophobic?
Well, there is a “Good News”; open MRI scanners are available in some hospitals or diagnosing centers to help patients having claustrophobia. In fact, BookmeriLab has centers in Delhi-NCR where it provides open MRI facilities at discount. Even if not, nowadays the doctor and radiologists are well trained to address such issues and will make you comfortable. However, open MRI lack the magnetic strength of a normal MRI machine. Usually, anesthesia (or painkilling medication) isn’t required in MRI scan but since you’re claustrophobic, you can go for it to help you relax. However, it is advisable to consult your physician beforehand to prescribe for anesthesia. You should bring along an escort to drive you home safely. You may need 8-10 hours of fasting if you choose to take anesthesia.
Will I be injected with a contrast dye before MRI scan?
I am glad you asked which means you are aware of what contrast is about. Gadolinium contrast media are also known as ‘dyes are chemical substances used in MRI scans to improve the quality of the MRI images. When injected into the body, it enables the radiologist to examine the images more accurately and determine the presence of any abnormality or disease. In view of this patients may be injected with a contrast agent before the scanning. However, people with severe kidney disease are susceptible to tissue and organ damage a rare disease called nephrogenic systemic fibrosis if injected with Gadolinium-based contrast agents.
Thus if you have kidney disease you should undergo MRI scan only if suggested by your doctor or physician after certain tests (usually Creatinine & Urea level). If you are allergic to contrast dye do not forget to tell your doctor.
Are there any side effects of MRI Scan?
The MRI, as the name signifies uses magnetic and radio waves which imply that there is no exposure to X-rays or any other damaging forms of radiation unlike Computed Tomography (CT) scan which makes use of the X-rays. As the scan is proven to be painless, so there should not be any side effects. However, the MRI scanner does make a lot of noise so you can ask for earplugs from the technician.
Is it Safe for Pregnant Women?
Pregnant women should not undergo an MRI scan unless otherwise advised by their physician based on medical urgencies. Although MRI do not make use of any damaging radiation such as X-rays but some specialists say that it may impact the foetus in the first 12 weeks of pregnancy and therefore scans should not be performed on pregnant women during this time. However, the effects of the long-term exposure to strong magnetic fields on a developing baby are also not yet established.
How to convince a child for an MRI scan?
Young children and babies may get claustrophobic and they may feel that they are deserted. It is advised to talk to them about the procedure and make them feel comfortable in every manner you can. Doctors and radiologists are well trained to address such issues. Normally young children and babies undergoing MRI scans are sedated so that they can stay still during the MRI scan because they move a lot when they’re awake especially when they are claustrophobic. Ask technicians to provide them with earplugs or headphones to block out the noise made by the MRI scanner.
Who should not undergo MRI Scan or MRI Scan side effects?
Any of the people falling under the category below should not undergo MRI Scan.
- Pregnant women in their initial weeks of pregnancy unless prescribed by the doctor. Pregnant women are also not suggested to get injected with contrast dye.
- Allergic to contrasts dye or similar past medical history.
- With severe kidney disease. As Gadolinium-based contrast agents may cause a rare disease called nephrogenic systemic fibrosis (thickening of the skin, organs and other tissues) in people with severe kidney failure.
- With metal inside their bodies such as surgical clips, cochlear implants, pacemakers, metallic strips, rods or artificial joints.
What is MRI Scan Cost in Delhi-NCR?
The cost is an MRI Scan depends on lab, locality, machine & body part under analysis. However, a non-contrast MRI Scan cost usually starts from Rs 6000-7000/- and it may go up to Rs 25000/- for a complicated scan. There will be extra charges in the range of Rs 3000-5000 for contrast. We have prepared a separate detailed guide on MRI Scan cost in Delhi, Gurgaon, Noida, Ghaziabad, Faridabad, Greater Noida & Jaipur along with MRI centers in these locations.