One can utilise MRI (Magnetic Resonance Imaging) to get pictures of the body’s soft tissues. Any tissue that hasn’t hardened due to calcification is considered soft tissue. It is a non-invasive diagnostic technique used to image many different body parts, including the liver, arteries, spinal cord, joints, brain, and muscles.
Its use is especially crucial for monitoring neurological disorders, including Alzheimer’s, dementia, epilepsy, and stroke, as well as for the surveillance and treatment of specific tumours like prostate and rectal cancer. Researchers have also used magnetic resonance imaging (MRI) scans of blood flow variations to deduce how neuronal activity changes within the brain; this type of MRI is known as functional MRI.
People who have metallic implants, such as pacemakers, or embedded metallic objects, such as shrapnel, may not be able to have an MRI due to the intense magnetic fields used in the procedure. The magnetic fields will remove the credit card’s magnetic strip if it is in their pocket!
How does MRI (Magnetic Resonance Imaging) operate?
An MRI method can produce an image of a bodily part using the hydrogen atoms contained in that part. All that is needed to make an atom of hydrogen is one proton and one electron. These spinning atoms have axes pointing in different directions. Water and fat, found practically everywhere in the body, are rich sources of hydrogen atoms.
Four parts are necessary for an MRI machine to function. The machine itself has a vast doughnut-like appearance. The individual whose body is to be scanned is put into the bore, the central hole. The potent superconducting magnet inside the donut creates a strong and steady magnetic field around the body. The magnetic field is activated when the body part to be scanned is at the center of the bore.
Since every hydrogen atom has an intense magnetic moment, the atom’s spin axis will point in the direction of any magnetic field. About half of the hydrogen atoms in the section that needs to be scanned have their axes pointing in one direction, while the other half are pointing in the opposite direction, thanks to the magnetic field that the superconducting magnet applies down the middle of the apparatus. There are barely a few mismatched atoms out of approximately a million in this nearly perfect matching.
The third component of the machine is a gadget that produces a radiofrequency pulse to the part beneath the scanner. Only the tiny population of “excess” atoms absorb radiation and become excited while the pulse is “on.” These atoms release the energy they have received and move back to their initial, lower-energy states when the pulse goes “off.”
The Larmor frequency is the pulse frequency that the “excess” atoms must absorb. The type of tissue in which the atoms are present and the strength of the magnetic field determine its value. The emissions are detected by the fourth and last part, a detector, which then transforms them into signals that are delivered to a computer for use in creating two- or three-dimensional photographs of that body part.
Pros of MRI
- emphasises extremely narrow areas, scans only a few millimetres broad, images the body from every useful angle, and displays various tissues in tiny steps that vary in tone from gray.
- Clinicians may also inject patients with a contrast agent, usually a gadolinium-based substance that decreases the T1 time in specific tissues, to improve their visibility in an MRI scan.
- don’t represent a threat because the atoms in the scanned area are unaffected when the magnetic fields are removed.
- Scanners do not have any long-term adverse effects.
Cons of MRI
- MRI devices are costly.
- Typically, scans cost Rs 10,000 or more apiece.
- For the scan to be completed, people must lie motionless for several minutes.
- The scan must be redone if the subject moves because the final image will be deformed.
- When the machine is working, loud noises are produced. This might be an extra cause of discomfort for the person.
