MRI Scan

MRI test, when used with other imaging techniques, can help diagnose various health conditions. In some MRIs, contrast dyes (often containing gadolinium, an element) are used to obtain more information about blood vessels in a particular area. 

• MRI is suitable for imaging of soft tissues and non-bony areas of the body. It generates better images of tendons, muscles, brain, ligaments, nerves, and spinal cord as compared to computed tomography (CT) scan and X-rays.
• This imaging helps differentiate between the grey and white matters of the brain and detects tumours and aneurysms (an outward bulge) in the brain.
• An MRI scan usually gives more accurate information about shoulder and knee injuries and conditions of the brain and spinal cord, e.g., venous malformations (abnormalities in the veins), hydrocephalus (presence of fluid in the brain), haemorrhage, and abscesses.
• Functional magnetic resonance imaging (fMRI) is a specialised MRI technique that helps detects the active parts of brain while the person is performing tasks that activate certain areas in brain.

As MRI scans do not use damaging radiations, they are suitable for diagnosing diseases and injuries that require repeated imaging.

Upright open MRI is also used to understand joint motion and alignment, especially in disease conditions such as femoroacetabular impingement (a condition where there is extra bone growth along the bones of the hip joint, giving it an irregular shape) and osteoarthritis.

A 3T MRI has the following benefits over a 1.5T MRI:

• Better image quality in different organs such as the spine, heart, breast, blood vessels and neuromuscular system.
• Improved imaging of brain lesions that occur in multiple sclerosis
• Reduced scan time
• Can help in visualising the small organs in paediatric patients.
• A 3T MRI is more sensitive to gadolinium dye compared to 1.5T MRI, thus requiring a lesser dose of the dye or providing better quality images in the same dose.

To prepare for an MRI, you might be asked not to drink or eat anything for 4 to 6 hours before the test. You will be asked to wear a hospital gown and put away your eyeglasses, pens, hairpins, credit cards, dental objects, hearing aids and jewellery in a locker. It is advisable to keep all your valuable items at home before coming for the test.

While taking an appointment for an MRI scan, remember to inform the physician if you have any of the following conditions:

• Permanent tattoos and eyeliner or body piercings
• Metal implants such as metal rods, screws and plates, and surgical staples
• Pregnancy
• A medical patch on your body
• Difficulty in lying down for about 30 to 60 minutes
• Previous bullet wound
• Recent placement of any artificial joints

Following steps are generally followed in an MRI test:

• If advised by the physician, a contrast dye is injected through an intravenous drip placed in the arm or hand.
• You will be asked to lie down on a table, which then slides into the spherical opening of the MRI scanning machine. Pillows or straps may be used to secure your position and avoid any movements during the scan.
• The technician conducting the MRI scan will be in a different room with scanner controls. The technician will be able to monitor you through a window connecting the rooms.
• You can communicate with the technician by pressing a call button. In case of any difficulty during the procedure, communication is also possible from inside the scanner.
• You will be given a headset with or without music or earplugs to block the noise made by the scanner. You might hear a click during the scan once the radio wave pulses and magnetic field release from the scanner.
• If required, the technician might instruct you to hold your breath for a few seconds. Do not resume breathing unless you are asked to.
• To achieve accurate results from the scan, it is essential to stay still during the scan. The slightest movement can create false images and affect the quality of the scan.

In an upright open MRI, you may need to sit, stand or lie down. You may have to change your postures during the scan. Similarly, for a reclining MRI you will be sitting in a reclining chair while the machine scans the concerned part of your body. Hold as still as you can during the scan. It takes two to four minutes while standing and five to 10 minutes when you are sitting or lying down.

An MRI does not produce any side effects from the radio waves and magnetic fields. Allergic reactions to the contrast dye occur in extremely rare cases. Magnetic fields generated while scanning can affect the working of implanted devices such as pacemakers and cochlear implants; therefore, it is essential to inform your physician of such implants before an MRI scan. Gadolinium, the most commonly used dye in MRI scans, is harmful to people with kidney problems. So, you should inform the technician if you have kidney problems.

Normal results:

A normal MRI scan represents that the body part being examined in the scan is not suffering from any health condition.

Abnormal results:

Results of an MRI scan are interpreted on the basis of signals received from the body part examined during the scan. For instance, cancer tissue cells provide different signals as compared to healthy tissue cells. Consulting your health care provider with the results will help resolve any queries and concerns about the results.

Disclaimer: This information is purely from an educational point of view and is in no way a substitute for medical advice by a qualified doctor.  All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis.