MRI Scan
- MRI scan means Magnetic Resonance Imaging scan
- Strength of the scanning machine is expressed in Tesla(T) like1T,3T
etc. NIMHANS has two 3T, one 1.5T and one 0.2T machine.
- This type of scanning does not use X-rays and hence MRI scan is not associated with any radiation induced risks and can be done in small children and in pregnant women.
- MRI scan gives more information in comparison with the CT Scan or
X-rays.
- MRI scan is the best technique currently available to assess the brain function.
- MRI scan can may take 30 minutes to one hour
- Sometimes a contrast (“Dye”) will be injected to get further
information
- MRI machine is not widely available and are costlier
When is an MRI Scan required?
- Tumours
- Epilepsy
- Stroke
- Infections
- Demyelination
- Dementia
- Vascular abnormalities
- Congenital diseases
- Spinalcord injuries and disc degeneration
- A typical mental illness
When MRI scan should not be done?
- MRI scan is usually not done inpatients withCardiac pacemakers and metallic implants.
- If you are pregnant MRI scan with contrast is usually avoided.
- If you had any history of allergic reactions there is an
Increased risk to contrast (“Dye”)
- If you have kidney failure then contrast is better avoided.
- Other diseases like Increased BP, Diabetes, Thyroid diseases etc also are associated with minor risks.
- Kindly inform your doctor if you have any of these conditions.
What are the types of MRI Scan?
- MR Angiography : Study of vessels which supply blood to the brain
- MR Venography: Study of vessels which drain blood from the brain
- MR Perfusion: Study of capillaries which supply blood to the brain
- Functional MRI: Study of brain function while you perform some task like moving hand or watching movie or naming objects.
- High resolution MR: Thin section study for better visualization of small structures like nerves, canals etc.
- MR Spectroscopy: Chemical analysis using MRI.
- Diffusion MRI: Study of cellular water movement
- MRF low analysis: Study of bulk flow of CSF and Blood
How do you prepare for MRI Scan?
- Can I take food prior to scan?
There is no need for fasting before an MRI scan
Only if MRI is done under anesthesia then you have to be fasting for minimum six hours prior to the scan. Fasting means not taking any solid, liquid, milk, milk based food and fruits. Plain water can be taken up to one hour before the scan.
Regular medicines should be taken with sip of plain water only. Medicines for diabetes should be taken after consulting your doctor only.
- Is any blood investigation required prior to scan?
Some patients might require routine blood tests and kidney function test prior to scan. Your doctor will advise if necessary.
- Do I have to remove jewellery and clothes before scan?
All metallic objects like earrings, chains, pendants, nose rings, hairpins, clips, coins, keys etc must be removed before scanning. You will have to change into a hospital dress after removing all clothing including the inner clothing before the scan
Mobile phones, memory card, ATM cards, Credit cards etc will be dysfunctional if it is taken inside the scan room. Hence all these have to be removed before entering MRI section and you will be scanned thoroughly prior to entering the MRI scan room.
- Should I be accompanied by someone.
It is advisable to bring your relative and friend when you come for scan