Magnetic Resonance Imaging (MRI) is a common medical imaging technique you might encounter at a hospital. You may have seen posters depicting a large, white machine resembling a closed cylinder with a person lying inside. This machine is an MRI scanner, a vital tool doctors use to diagnose various conditions and monitor treatment progress.
What is an MRI Scan?
MRI is a radiology scanning technique that utilizes powerful magnets, radio waves, and computer processing to create detailed images of the body’s internal structures. An MRI machine typically takes the form of a large tube surrounded by a strong circular magnet. During an MRI examination, the patient is positioned on a movable bed that slides into the magnet’s bore. This process generates a powerful magnetic field, aligning the protons of hydrogen atoms within the body. Subsequently, radio waves are emitted, causing these aligned protons to produce signals. These signals are detected by receivers within the MRI machine. Finally, a computer processes these received signals to construct cross-sectional images of the body.
The resulting MRI images are exceptionally detailed, capable of detecting even subtle changes in the body’s internal structures. In certain procedures, a contrast material, such as gadolinium, may be administered intravenously to enhance image clarity and diagnostic accuracy.
Why are MRI Scans Necessary?
MRI scans are used to visualize organs, bones, and soft tissues within the body, including the nervous system. Physicians order MRI scans to diagnose medical conditions, injuries, or to assess the effectiveness of ongoing treatments. MRI can be performed on virtually any part of the body.
Often, MRI scans become necessary when other imaging techniques, such as X-rays or CT scans, do not provide sufficient information for accurate diagnosis and treatment planning. If a doctor requires a more detailed view after initial scans, an MRI may be recommended.
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MRI scans are valuable in examining a wide range of conditions, including:
- Blood vessel damage or blockages
- Heart conditions
- Brain damage
- Cancer detection and monitoring
- Multiple sclerosis (MS)
- Bone infections
- Joint injuries
- Nerve problems in the neck
- Spinal cord injuries
- Stroke
- Eye disorders
- Inner ear problems
Furthermore, MRI scans are utilized to assess the health of organs like the breasts and ovaries in women, kidneys, liver, pancreas, and the prostate gland in men.
Advantages of MRI Scans
MRI scans offer distinct advantages over other imaging modalities. A key technological strength lies in their ability to characterize and differentiate tissues based on their physical and biochemical properties. MRI can also evaluate blood flow, spinal fluid dynamics, and organ contractions and relaxations. The high resolution of MRI images significantly aids doctors in accurate interpretation and diagnosis.
Further benefits of MRI scans include:
- Non-invasive nature, requiring no surgery.
- Absence of ionizing radiation.
- Low incidence of allergic reactions to MRI contrast agents.
- Superior clarity and detail in soft tissue imaging compared to other techniques.
- Capability to generate hundreds of images from almost any angle and orientation.
- Broad coverage, imaging large portions of the body.
- Utility in detecting cancer spread and guiding optimal treatment strategies.
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What are the Risks & Side Effects?
Although MRI scans do not employ radiation like CT scans, they utilize strong magnetic fields. These magnetic fields are powerful enough to affect metallic objects in proximity. This poses a significant risk for patients with metallic implants, such as pacemakers. Such patients should not enter an MRI machine environment. Other risks and side effects include:
- Noise: MRI machines can generate loud noises, reaching up to 120 decibels in some types. Patients are typically provided with earplugs or headphones before entering the scanner.
- Nerve Stimulation: A twitching sensation may occur due to the magnetic fields interacting with nerves.
- Contrast Agent Issues: Patients with severe kidney failure requiring dialysis may face complications with gadolinium-based contrast agents.
- Pregnancy Concerns: MRI scans, particularly with contrast agents, are generally not recommended during the first trimester of pregnancy due to potential effects on the fetus.
- Claustrophobia: Traditional MRI machines are enclosed and can trigger claustrophobia in some individuals. Open MRI machines are now available, offering a more comfortable experience for patients with fear of confined spaces.
Read Also: Radiology Examinations: Functions, Types, and Detectable Medical Conditions
Reviewed by:
Radiology Doctor Team of Primaya Hospital Bekasi Barat :
Dr. Viva Agusnialy,Sp.Rad
Dr. Sri pardiastiti,Sp.rad
Dr. Masbimoro,Sp.Rad
Dr. Dewi Agus Setyawati,Sp.Rad
References:
https://www.webmd.com/a-to-z-guides/what-is-an-mri#1