Magnetic Resonance Imaging (MRI)

Updated on September 18, 2026Author:NEXT IAS Contributors

The full form of MRI is Magnetic Resonance Imaging (मैग्नेटिक रेजोनेंस इमेजिंग). It uses strong magnetic fields and radio waves to generate high resolution 3D images of soft tissues without using harmful ionising radiation. Interestingly, the MRI scanners use liquid helium to supercool the superconducting electromagnets and generate magnetic fields about 30,000 times stronger than Earth's gravity. The MRI machine aligns hydrogen atoms in the human body. The radio pulses emit signals as they re-align to map organs, brain and ligaments.

How MRI Works?

Magnetic Resonance Imaging or MRI uses a powerful magnetic field, radio waves and a computer to create a detailed image of the body. The MRI works primarily by detecting signals from hydrogen nuclei because the human body contains a large amount of water and fat.
The radio frequency pulses temporarily disturb this alignment. When the pulses stop, the protons return to their original state and release the signals. The receiver coils detect these signals and the magnetic field tracks the location of signals.
Various tissues release signals at different frequencies. Thus the computer converts them into contrasting images. The MRI may use special sequence or gadolinium contrast to highlight particular tissues, blood vessels or abnormalities. It does not use ionising radiation.

Non Medical Use

S.No.	Field	Use of MRI
1	Materials science	It is used in the studies of internal structures, moisture distribution and defects in materials.
2	Chemical research	It is used to analyze molecular composition and chemical environments through NMR-based techniques.
3	Food science	It is used to measure the water movement, texture, composition and quality of food products.
4	Agriculture	It is used to examine seeds, roots, fruits, soil moisture and plant-water movement.
5	Archaeology	It is used to investigate internal structures of artefacts without physically damaging them.
6	Petroleum industry	It is used to study rock pores, fluid movement and reservoir characteristics.
7	Engineering	It is used for testing components, composite materials and fluid-flow behaviour.
8	Pharmaceutical research	It is used to examine drug formulation, diffusion and delivery systems.
9	Forensic science	It is used to analyse objects or biological samples without destructive sampling.
10	Veterinary science	It is used for Imaging the animals for diagnosis and research.

What is an MRI Test?

An MRI test is a painless, non-invasive imaging scan or test which uses powerful magnetic fields, radio waves and computer processing to produce detailed pictures of organs, tissues and other body parts. During an MRI scan or test, the patient lays down on a movable table that slides onto a tunnel-shaped scanner (in case of Closed MRI system). The patients are asked not to move their body during the image capture by MRI machine. Sometimes, a contrast agent is injected into the body to improve the image quality and clarity. An MRI generally takes about 30 to 60 minutes and doesn't make use of X-ray radiation.

Comparison of Open and Closed MRI

S.No.	Feature	Open MRI	Closed MRI
1	Design	It is more open around the patient.	It is an enclosed cylindrical tunnel.
2	Patient comfort	It is usually more comfortable for claustrophobic or larger patients.	It may feel confined to some people.
3	Magnetic strength	It is often available in lower-field strength. However, modern systems may vary.	It is usually available in high-field strength.
4	Image quality	It may be lower for some of the MRI scans.	It generally provides high-resolution images.
5	Scan duration	It may take longer for certain MRI scans.	It is often faster than an open MRI system.
6	Suitable for	Some patients require greater space or comfort.	It provides a detailed examination which requires stronger imaging capability.
7	Availability	It is less widely available.	It is more commonly available.
8	Limitations	It is not suitable for every MRI scan or test.	It requires careful screening for implants and claustrophobic patients.

History

Magnetic Resonance Imaging (MRI) emerged from nuclear magnetic resonance research which was initially used for chemical analysis. In the early 1970s, Paul C. Lauterbur had introduced magnetic-field gradients that enabled signals from hydrogen nuclei to be converted into images. Afterwards, Peter Mansfield has developed faster ways for acquiring signals and creating clear images. Various early experiments produced images of body parts such as the hand and finger before the technology became advanced for clinical use.

Over the period of time, MRI has developed into an important diagnostic tool because it can provide detailed images of soft tissues without using ionizing radiation. In 2003, Lauterbur and Mansfield received the Nobel Prize in Physiology or Medicine for discoveries related to MRI.

Difference Between MRI and CT Scan

S.No.	Basis	MRI	CT scan
1	Full form	Magnetic Resonance Imaging	Computed Tomography
2	Main technology	It uses magnetic fields and radio waves.	It uses X-rays and computer processing.
3	Ionising radiation	It is not used in MRI scans.	It is used in CT scans.
4	Soft-tissue detail	It provides detailed and excellent information on soft tissues inside the human body.	It provides valuable information but often less detailed than MRI for many soft tissues.
5	Bone imaging	It is useful particularly for bone-marrow and soft tissues around bones.	It is usually excellent for fractures and dense bones.
6	Speed	It is usually slower than CT-scan.	It is usually faster than MRI.
7	Noise	MRI is often loud.	CT-scan is generally quieter.
8	Claustrophobia	It is more likely in closed systems.	It is commonly less likely in CT-scan systems.
9	Metal and implants	It requires a strict safety screening process.	Most of the metal implants are acceptable but may create artefacts.
10	Contrast agent	The MRI scan may use Gadolinium.	The Iodine-based contrast may be used in CT-scan.
11	Common uses	The MRI is often used for soft tissue inside the body such as brain, spine, joints, ligaments, muscles, tumours and other soft tissues.	The CT-scan is often used for trauma, fractures, lungs, bleeding and rapid emergency assessment.

FAQs about MRI

What is the full form of MRI?

The MRI full form is Magnetic Resonance Imaging. It is a technique to take images and uses magnet and radio waves to study the soft tissues inside the body.