Innovations in Biotechnology and Medical Sciences

Magnetic Resonance Imaging (MRI) and the Science behind


From UPSC perspective, the following things are important :

Prelims level: MRI and its working principle

Mains level: NA

Why in the news?

  • Magnetic Resonance Imaging (MRI) revolutionized medical diagnostics, offering non-invasive insights into soft tissues.
  • The pioneering efforts of Paul Lauterbur and Peter Mansfield led to its commercialization, earning them the Nobel Prize in Medicine in 2003.

What is MRI?

  • Magnetic resonance imaging (MRI) is a non-invasive diagnostic procedure used to obtain detailed images of soft tissues within the body.
  • It is particularly valuable for imaging sophisticated structures like the brain, cardiovascular system, spinal cord, joints, muscles, liver, and arteries.
  • MRI is instrumental in diagnosing and monitoring various conditions, including cancer, neurological disorders (such as Alzheimer’s and stroke), and cardiovascular diseases.
  • Functional MRI (fMRI) can also assess brain activity by monitoring changes in blood flow.

Working Principle:

  • MRI utilizes the magnetic properties of hydrogen atoms (one proton with one electron around it), which are abundant in water and fat molecules found throughout the body.
  • The MRI machine generates a powerful magnetic field, aligning hydrogen atoms within the body.
  • Radiofrequency pulses are then applied, causing hydrogen atoms to absorb energy and emit signals.
  • These emitted signals are detected by sensors and processed by a computer to create detailed images of the body’s internal structures.

Components of an MRI Machine:

The MRI machine consists:

  • Superconducting Magnet: Large magnet (superconducting magnet) that produces a powerful and stable magnetic field.
  • Gradient Coils: Gradient magnets produce smaller magnetic fields with varying strengths and directions, allowing for precise imaging of specific body areas.
  • Radiofrequency Coils: This emit radiofrequency pulses to excite hydrogen atoms in the body. The frequency of pulse the ‘excess’ atoms have to absorb is called the Larmor frequency.
  • Detectors: It capture emitted signals from hydrogen atoms and convert them into image data for analysis.

Advantages of MRI:

  • High-Resolution Imaging: MRI offers high-resolution imaging with excellent tissue contrast, allowing for accurate diagnosis and treatment planning.
  • Versatile Viewing Angles: It can visualize structures from various angles without the need for repositioning, providing comprehensive information.
  • Safety and Non-Invasiveness: MRI scans are non-invasive and do not involve ionizing radiation, making them safe for repeated use.
  • Enhanced Image Quality: Contrast agents can enhance image quality by highlighting specific tissues or abnormalities.

Limitations of MRI:

  • High Costs: MRI machines are expensive to purchase and maintain, resulting in high healthcare costs for patients.
  • Requirement for Patient Stillness: Patients undergoing MRI scans must remain still for extended periods to prevent image distortion, which can be challenging for some individuals.
  • Discomfort or Anxiety: The strong magnetic fields and loud noises produced during MRI scans may cause discomfort or anxiety for patients.
  • Limitations with Metallic Implants: Certain metallic implants or objects can interfere with MRI scans, limiting their use in individuals with such implants.


[2020] With the present state of development, Artificial Intelligence can effectively do which of the following?

  1. Bring down electricity consumption in industrial units
  2. Create meaningful short stories and songs
  3. Disease diagnosis
  4. Text-to-Speech Conversion
  5. Wireless transmission of electrical energy

Select the correct answer using the code given below:

(a) 1, 2, 3 and 5 only

(b) 1, 3 and 4 only

(c) 2, 4 and 5 only

(d) 1, 2, 3, 4 and 5

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