MRI - SCI & TECH
News: What is magnetic resonance
imaging? | Explained
What's in the news?
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Magnetic Resonance Imaging (MRI) revolutionized
medical diagnostics, offering non-invasive insights into soft tissues.
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The pioneering efforts of Paul Lauterbur and Peter Mansfield led to its commercialization,
earning them the Nobel Prize in Medicine in 2003.
MRI:
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Magnetic resonance imaging (MRI) is a non-invasive
diagnostic procedure used to obtain detailed images of soft tissues within the body.
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It is particularly valuable for imaging
sophisticated structures like the brain,
cardiovascular system, spinal cord, joints, muscles, liver, and arteries.
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MRI is instrumental in diagnosing and monitoring
various conditions, including cancer, neurological disorders (such as
Alzheimer’s and stroke), and cardiovascular diseases.
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Functional MRI (fMRI) can also assess brain activity by monitoring changes in
blood flow.
Working Principle:
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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.
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The MRI machine generates a powerful magnetic
field, aligning hydrogen atoms within the body.
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Radiofrequency pulses are then applied, causing
hydrogen atoms to absorb energy and emit signals.
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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:
1. Superconducting
Magnet:
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Large magnet (superconducting magnet) that produces
a powerful and stable magnetic field.
2. Gradient Coils:
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Gradient magnets produce smaller magnetic fields
with varying strengths and directions, allowing for precise imaging of specific
body areas.
3. Radiofrequency Coils:
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This emits radiofrequency pulses to excite hydrogen
atoms in the body. The frequency of pulse the ‘excess’ atoms have to absorb is
called the Larmor frequency.
4. Detectors:
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It captures emitted signals from hydrogen atoms and
converts them into image data for analysis.
Advantages of MRI:
1. High-Resolution
Imaging:
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MRI offers high-resolution imaging with excellent
tissue contrast, allowing for accurate diagnosis and treatment planning.
2. Versatile Viewing
Angles:
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It can visualize structures from various angles
without the need for repositioning, providing comprehensive information.
3. Safety and
Non-Invasiveness:
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MRI scans are non-invasive and do not involve
ionizing radiation, making them safe for repeated use.
4. Enhanced Image
Quality:
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Contrast agents can enhance image quality by
highlighting specific tissues or abnormalities.
Limitations of MRI:
1. High Costs:
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MRI machines are expensive to purchase and
maintain, resulting in high healthcare costs for patients.
2. Requirement for
Patient Stillness:
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Patients undergoing MRI scans must remain still for
extended periods to prevent image distortion, which can be challenging for some
individuals.
3. Discomfort or
Anxiety:
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The strong magnetic fields and loud noises produced
during MRI scans may cause discomfort or anxiety for patients.
4. Limitations with
Metallic Implants:
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Certain metallic implants or objects can interfere
with MRI scans, limiting their use in individuals with such implants.