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 dependent 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.
The applications of MRI are ever expanding, and now may be even used to assess the small and large bowel for masses and obstruction, as well as conditions such as Crohn's disease and cancer. Whole body MRI may be performed to evaluate any region required in order to screen for diseases and may find a role as a public health initiative.
MRI has the ability to even identify early cartilage breakdown at the molecular level prior to the development of a visible defect and overt arthritis utilising a technique known as delayed Gadolinium Enhanced Magnetic resonance Imaging of Cartilage, or dGEMRIC.
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. For this reason, MRI is of particular use in the evaluation of paediatric patients, whose organs are more radiosensitive than adults.
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.
Wide Bore MRI Scanner
For more information read:
Melbourne Radiology Clinic - Patient Fact Sheet on Magnetic Resonance Imaging (MRI)
For more information read:
Melbourne Radiology Clinic - Paediatric MRI (for Children under 16) - Fact Sheet for Parents
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