WHAT IS MRI
FULL FORM OF MRI: magnetic resonance imaging
Definition of MRI
Magnetic Resonance Imaging is a scan test that uses strong magnetic field and radio waves to produce images of the body organs in great detail.
MRI Basic Principles
1. MRI is able to scan images of water, and water is present in all tissues of the body, so soft tissue pictures come out in great detail.
2. Hydrogen,which is part of the water molecule, is the principle underlying the basic technique of MRI scan.
3. Radio waves are sent in the body that are absorbed according to the hydrogen present in the body and the emanating signals are recorded to create detailed digital images of the body organs , parts or soft tissues, these are then analyzed.
History of MRI
1952- Herman Carr produced a one-dimensional MRI image as his PhD thesis at Harvard.
1960 -Vladislav Ivanov filed a document with the USSR State Committee for Inventions and Discovery for a Magnetic Resonance Imaging device, approved in 1970s.
1971 - Raymond Damadian reported thatthat tumours and normal tissue can be distinguished in the body by nuclear magnetic resonance ("NMR").
1972 – Raymond Damadian filed his patent for an MRI machine.
MRI scan Facts
1. Teeth & Bones do not appear in the scan as they contain little water.
2. Tissues surrounding bones such as spinal cord are finely observable.
3. Provides knowledge of -blood vessels,blockage in blood vessels, damages in arteries, the flow of blood bleeding & infection & blood vessel problems.
4. Since MRI does not use any ionizing radiation its use is recommended in preference to CT scan test.
5. It is a painless procedure.
Area of Application of MRIs
Being a more sensitivetest than CT, it is the preferred choice for small tumours, conditions of the central nervous system like v MRI is the investigative tool of choice for neurological cancers, cerebrovascular disease, demyelinating diseases, dementia infections and epilepsy.
1. When applied for the Musculoskeletal system it is extremely useful in soft tissue tumours.Spinal imaging& assessment of joint diseases.
2. Hepatobiliary MR is used to characterize lesions of the liver, pancreas and bile ducts. By use of opposed-phase imaging, diffusion-weighted & dynamic contrast enhancement sequences, we can evaluate diffuse or focal disorders of the liver.
3. By fMRI or Functional MRI we can see how different parts of the body external stimuli like the hemodynamic response to transient neural activity which happens due to changes in the ratio of oxygenated and deoxygenated haemoglobin. This is done by the BOLD test-Blood oxygenation level dependent fMRI . This has applications in behaviouraland cognitive research as well as in planning neurosurgery of specific brain areas.
4. Oncological MRIhas a role in the diagnosis, staging, and follow-up of tumors and is the investigatorschoice in preoperative staging of prostrate and rectal cancers.
5. MRA - MagneticResonance Angiography)is able to generate pictures of the arteries; same can be evaluated for stenosis (abnormal narrowing) oraneurysms (vessel wall dilatations, at risk of rupture). Other arteries of the neck and brain, thorax, abdominal aorta, the renal arteries and the legs can also be evaluated.
6. MRV-Magnetic Resonance Venography is done to image pictures of Veins.
7. MRS -Magnetic Resonance Spectroscopy (MRS) is used to measure the different levels of metabolites in body tissues. This is used to diagnose certain metabolic disorders (especially of the brain) and provide information on tumour metabolism.This is done by the combination of imaging & spectroscopic methods.
8. Real-time MRImeans continuousfilming of moving objects in real time.This new method gives important information about diseases of the joints and the heart.
9. Interventional MRI- Used in surgery asintra-operative MRI in which the MRI is used for surgical procedures or guide in subsequent surgical work.
10. Magnetic Resonance Guided Focused Ultrasound - In MRgFUS therapy, ultrasound beams are focused on the tissue to be destroyed—suitably guided by using MR thermal imaging—with temperatures rising above 65 °C (150 °F) to achieve precise ablation of the diseased tissue. The MR imaging is able to provide quantitative, actual, thermal images of the treated area.
11. Multinuclear imaging-Right now, it is more on research lines but potential is high. Inhaled hyperpolarized Helium can be used to image the distribution of air spaces within the lungs. Injectable solutions for angiography and perfusion imaging.For functional imaging of the brain. Multinuclear imaging can give distribution of lithium in the brain, helping in treating bipolar disorders,etc.
USES OF MRI
– of tiny lesions of multiple sclerosis on brain and spinal tissue
- joint injuries
In detection of
- injuries in head
Provides knowledge of
MRI can be done for:
|1. MRI abdomen lower
2. MRI abdomen lower +MRCP
3. MRI abdomen upper
4. MRI abdomen whole
5. MRI angiography , per part
6. MRI ankle joint ,single
7. MRI ankle joint , both
8. MRI brachial plexus
9. MRI brain+ angiography
10.MRI brain+ diffusion study
12.MRI brain + venography
13.MRI blood vessels(MRI angiography)
17.MRI elbow, joint both
18.MRI elbow joint single
19.CV Junction plain and contrast MRI
20.CSF flow study plain MRI
21.Dorsal spine plain MRI
22.Dorsal spine contrast MRI
|23.Functional MR (BOLD) perfusin plain MRI|
24.Functional MR(BOLD)perfusion plainMRI
26.MRI functional ( per region)
27.MRI gall bladder
33.MRI knee joint,single
34.MRI knee joint , both
35.MRI IAM screening
37.MRI lumbar spine
39.MRI musculoskeletal, one part
40.Myolography plain MRI
41.Myolography plain MRI
|45.Orbit contrast MRI
46.Orbit plain MRI
50.MRI screening,per part
51.MRI screening,joint single
52.MRI screening joint both
53.MRI screening whole
55.MRI temporomandibular joints ,single
56.MRI temporomandibuular joints , both
57.MRI thoracic spine
59.MRI urinary tract
61.MRV : magnetic resonance venography (for veins)
62.MRI vertebral artery(VA)
63.MRI wrist joint,single
64.MRI wrist joint , both
65.MRI+MRA + SPECTROSCOPY brain
1. You are required to wear a gown which should not have any metal button, zips or any other metal bearings as it causes blurring of the image.
2. You may be asked not to eat for 4-6 hours before going for MRI.
3. Before going for the MRI scan the doctor may ask you if you have any kidney problems, whether you are on dialysis.
4. The doctor also asks you about any metal implants you have in the body like artificial valves, inner ear implants, artificial joints etc. as any kind of metal inside the body can cause problems with the clarity of images and provide blurred images.
5. Remove jewellery, spectacles, credit cards, hairpins, metal zippers, pins ,watches or any other kind of metal item before going for MRI scan.
6. You may also be asked if you are claustrophobic( fear of closed spaces).
7. A contrast dye called gandolinium is swallowed or injected for better images.
8. You must also inform the doctor if you are pregnant as contrast dye can be allergic or in future may pose a threat.
9. Moving during the scan can cause blurring of the image so you are asked to stay still.
MRI scan results
A typical MRI scan takes 40 to 60 min or more depending on the kind of MRI scan you are going for. The radio waves are sent to corresponding body part or organ and signals accordingly are received and an image is created which can be saved in a computer and the doctor interprets the results.
Risks of MRI
1. MRI scan is as such better than X-Ray and CT Scan as it does not use ionising radiations which can prove to be harmful.
2. MRI has no side effects.
3. If you are pregnant or have any kidney problem or are on dialysis, the same must be informed to the doctor.
4. As this test is magnetic resonance based, any metal implants, pieces inside the body may shift the magnetic fields, causing inaccuracy in the results.
Cost of MRI in delhi
1. The cost of MRI depends on the kind of MRI scan you are going for.
2. Also the cost of plain MRI( without contrast dye) is low as compared to MRI scan with contrast dye.
3. The approximate price of MRI in delhi ranges between 6000-12000 rupees and can be more.
Some MRI Scan Tests-
1. Cost of MRI Brain in Delhi
Through Medcross,You can avail more than 50% discount on mri tests in delhi.
MRI machineA typical MRI machine consists of the following:
2.Radio frequency coils