Understanding Magnetic Resonance Imaging | 09 May 2024

Source: TH

Why in News?

Recently, Magnetic Resonance Imaging (MRI) has been a topic of discussion as an indispensable tool for non-invasive exploration inside the human body.

What is Magnetic Resonance Imaging (MRI)?

• About:
  • MRI is a non-invasive diagnostic procedure used to obtain images of soft tissues within the body.
    • Soft tissue is any tissue that hasn’t become harder through calcification. Calcification of soft tissue is a condition where calcium salts accumulate in soft tissue, causing it to harden.
  • It is widely utilised for imaging various body parts such as the brain, cardiovascular system, spinal cord, joints, muscles, liver, and arteries.
    • Unlike X-rays, which use radiation, MRI scans leverage powerful magnets and radio waves to create detailed images of soft tissues within the body.
  • Professor Paul C. Lauterbur and Peter Mansfield won the 2003 Nobel Prize in Physiology or Medicine for their innovative research which resulted in the invention of MRI.
• Working Principle of MRI:
  • Hydrogen Atom Utilisation: An MRI procedure utilises hydrogen atoms present in the body part being scanned.
  • MRI Machine Components: The MRI machine consists of four essential components, including a superconducting magnet, a radiofrequency pulse emitter, and a detector.
  • Magnetic Field Application: The superconducting magnet produces a strong and stable magnetic field around the body, causing the hydrogen atoms' spin axes to align either parallel or antiparallel to the field.
  • Radiofrequency Pulse Emission: A radiofrequency pulse is emitted into the body part under the scanner, exciting only the small population of unmatched hydrogen atoms.
  • Signal Detection and Image Formation: The emitted energy from the excited atoms is detected by a receiver and converted into signals.
    • These signals are then used by a computer to create two- or three-dimensional images of the scanned body part.
• Importance of MRI: MRI plays a crucial role in observing and treating cancers like prostate and rectal cancer, as well as tracking neurological conditions including Alzheimer's, dementia, epilepsy, and stroke.
  • Additionally, researchers use MRI scans to study changes in blood flow, aiding in understanding brain activity, known as functional MRI.
• Advantages of MRI:
  • High Precision: MRI machines scan specific body portions with gradient magnets.
  • Safety: MRI scans pose no long-term harm, and magnetic field effects are well-studied.
  • Early Disease Detection: MRI aids early detection of diseases like cancer and multiple sclerosis.
  • Minimally Invasive Procedure: MRI is safe and comfortable, unlike surgery, benefiting children and the elderly.
• Disadvantages of MRI:
  • Cost: MRI machines are expensive to purchase and maintain, leading to high diagnostic costs for patients.
  • Discomfort and Claustrophobia: Patients must lie still for extended periods inside the MRI machine, which can be uncomfortable, especially for claustrophobic individuals.
  • Limited Imaging Capability: MRI struggles to image certain tissues like bone, air, and some types of implants effectively due to their physical properties.
  • Strong Magnetic Fields: The powerful magnetic fields used in MRI can pose potential risks for patients with certain medical implants (e.g., pacemakers) or metallic objects lodged in their bodies.