MRI Scan – RADIOLOGY SERVICES – Magnetic Resonance Imaging
While CT Scans use X-rays, Magnetic Resonance Imaging (MRI) uses magnetic fields and radio waves to produce detailed images of body’s internal organs. MRI scans are particularly useful in generating high quality images of soft tissue inside the brain, and other organs located inside abdomen, pelvis, and chest. The doctor suggests an MRI when the results of X-Ray or ultrasound examinations are not clear or satisfactory in making an accurate diagnosis.
- What are some of the common applications of MRI Scan?
MRI scans are efficient in diagnoses of a wide range of pathological disorders in various parts of the body. The common applications of this examination without any radiation exposure include the following –
- Brain – to detect cancers and strokes.
- Spine and musculoskeletal disorders.
- Heart – Aorta, coronary arteries, blood vessels, heart chambers are scanned to study size and thickness in order to diagnose heart attacks and progressive heart diseases.
- Breasts – Traditional X-Ray mammography can be replaced by MRI scan for early diagnosis of breast cancers in women.
- Reproductive Organs – Male and female reproductive systems, pelvis, hips and bladder can be scanned to detect various diseases and disorders.
Specialized MRI Scans:
Diffusion MRI – The brain suffers an ischemic stroke due to disease or lack of oxygen and nutrition. Within 5 to 10 minutes of the onset of stroke symptoms, the Diffusion MRI can be very useful in making a correct diagnosis.
Magnetic Resonance Angiography- It can generate high quality pictures of arteries so that the doctor can detect stenosis (abnormal narrowing) or aneurysms (vessel wall dilatations with risk of rupture).
Magnetic Resonance Venography – It helps in the study of detailed images of veins to detect abnormalities such as narrowing or dilation of veins.
Magnetic Resonance Spectroscopy (MRS) – It is a research technique that is used to collect a wealth of chemical information on a particular region of the brain in order to detect strokes, seizures, degenerative disorders, tumours, and depression.
- What does the MRI equipment look like?
The conventional MRI unit has a tube like structure called the bore which contains the magnet, scanner, patient table, and coils which adjust the gradient, shimming, and radio frequency. This unit is connected to the computer located in an adjacent shielded room.
- How is the procedure performed?
- The patient lies down on the table which slides into the bore.
- The radiologist in the next room instructs the patient using the intercom and then starts the MRI imaging sequences.
- The patient should not move during image sequencing, but he or she can move when the technician gives instructions.
- The exam will take between 25 to 45 minutes depending on the number of imaging sequences which vary from 2 to 6.
- A contrast material such as gadolinium may be injected to view tissues and blood vessels more clearly. This usually happens on doctor’s advice.
- The radiologist takes more images if needed and prepares the final report after interpretation and analysis of the results.
Note: Children can go through the exam in the presence of an adult who may have to wear a protective cover.
- What will I experience during the MRI procedure?
- MRI causes no sensation of pain during or after the exam.
- Some patients find it difficult to stay still inside the bore.
- Some patients complain that they are feeling “closed in” due to fear.
- If a contrast injection is used, there may be discomfort, pain or cooling sensation in the injected area.
- Many patients complain of loud tapping or knocking noises during certain phases of imaging sequence. Ear plugs can be used to shut out the noise.
- Modern MRI scanning machines reduce noise decibel levels up to 97% and make the patient feel more comfortable.
- Who interprets the results and how do I get them?
The radiologist with expertise in MRI, CT, and other radio-diagnostic services analyzes the images to prepare a report. The patient can collect the report on the same day or following day. At our centre, You can also collect a permanent CD record after paying a nominal fee. Inform our help desk, if you require a CD copy.
- What are the benefits vs. risks of MRI Scan?
- This is the best scanning method for soft-tissue structures of the body, as the images are much clearer and detailed.
- Physicians evaluate MRI scans and offer more efficient diagnosis.
- MRI contrast material is less allergenic than iodine-based materials used in conventional x-rays and CT scan methods.
- MRI scan is more efficient than x-ray angiography for diagnosing heart and cardiovascular diseases as it is faster and less invasive.
- The biggest benefit of MRI is that it is totally free of radiation exposure.
Pregnancy- MRI has to be avoided by pregnant women in the first 12 weeks of pregnancy. Doctors recommend other imaging methods such as ultrasound, unless MRI becomes essential and inevitable.
Projectiles – The MRI scanner room should not have ferrous objects and devices as the strong magnetic field inside the bore can attract them causing injury to the patient.
Ferromagnetic Foreign Bodies – Some patients have lodged shell fragments or metallic implants such as surgical prostheses or aneurysm clips inside them. Such patient risk’s trauma if the magnetic and radio frequencies inside the MRI bore interact with these inserted devices. The doctor’s advice is very important as the recommendation varies from patient to patient.
Kidney Patients – Those with chronic renal problems can develop nephrogenic fibrosis due to the use of Gadolinium based contrast material. The injection should not be administered to such patients.
Other Risks – Thermal injury from radio-frequency induced heating of any implanted device and its failure.
MRI examination does not require special preparation unless advised by the doctor, radiologist, or supporting staff. Food and drink can be consumed in a normal manner along with prescribed drugs.
Make up should be avoided as cosmetics can be harmful during MRI exam. Watches, jewellery, mobile devices, and other metallic objects will not be permitted inside the MRI room. The centre provides safety locker in case you do not want to leave them unguarded.
MRI exam requires you to change into scrubs or sanitary clothing to ensure that you do not have any metallic or prohibited objects with you.
The technologist will interview you and offer guidance in filling up a screening form. Your consent and understanding of all the risks and benefits are very important.
You should also be open and provide information to the doctor or radiologist concerning your current health status, diseases, and metal implants.
Patients have to remove the following accessories and items before entering the MRI scanning room –
- Purse, credit/debit cards, wallet, money clip, or other cards with magnetic strips.
- Electronic devices, beepers, and cell phones
- Metal bangles, chains, jewellery, watches
- Pens, keys, paper clips, coins
- Clothes with metal buttons, zipper, snaps, hooks, threads, etc.,
- Hairpins, clips, shoes, belt buckles, safety pins.
Ferromagnetic objects and other items listed below are not permitted inside the MRI exam as they can be hazardous to the patients’ health –
- Implantable Cardioverter Defibrillator (ICD)
- Aneurysm clip
- Hearing aids
- Implanted drug infusion device
- Foreign metal objects, especially inside or near the eye
- Dentures/teeth with magnetic keepers
- Medication patch (i.e., trans-dermal patch) that contains metal foil
- Shrapnel or bullet wounds
- Permanent cosmetics or tattoos
- Other implants that have metal or magnets
Warning – Always check with the Radiologist or MRI technologist if you have queries or concerns regarding implants or other health conditions. Patients who have undergone surgery involving brain, heart, ear, eye, or blood vessels should mandatorily seek advice on risks of MRI procedure.