Magnetic Resonance Imaging (MRI) is the most sophisticated imaging modality that has revolutionised modern radiology.
This technology uses a large magnet to align water molecules in the body in a particular direction. Radiofrequency (energy) waves, similar to those used in a commercial radio, enter the body, manipulating the magnetic alignment of the molecules. When these radiofrequency waves are switched off, the water molecules then release the energy that was imparted to them, a process known as “resonance”.
The manner in which molecules release this energy differs on the specific type of tissue and is dependant on other factors, including the local magnetic field in our body at the molecular level. This released energy is then detected by a coil as a signal, which is then digitised and processed to form an image.
Magnetic Resonance Imaging is extremely versatile and sensitive, with the ability to differentiate between different body tissues, such the grey and white matter of the brain, cartilage, bone, tendons, fluid and fat.
This is one of the advantages of MRI over ultrasound. For example, an ultrasound scan will provide excellent resolution of the rotator cuff tendons of the shoulder, but is unable to exclude any problem inside the shoulder joint, such as a cartilage or labral tear, arthritis or bone injury. MRI can look at all these structures.
Similarly, though CT can obtain excellent views of the brain, MRI can differentiate with far greater resolution the grey and white matter of the brain. MRI technology uses energy in the radiowave spectrum and thus does not result in any radiation exposure.
Referring doctors are welcome to discuss with our radiologist the imaging needs of their patients and whether MRI is suitable for their patient’s medical condition.
For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Magnetic Resonance Imaging (MRI)
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