Magnetic Resonance Imaging (MRI)
MRI scans create diagnostic images without using harmful radiation
Magnetic Resonance Imaging (MRI) uses a strong magnetic field and radio waves to generate images of the body that can’t be seen well using X-rays or CT scans, i.e. it enables the view inside a joint or ligament to be seen, rather than just the outside.
Commonly used to examine internal body structures to diagnose strokes, tumors, spinal cord injuries, aneurysms and brain function.
As we know, the human body is made mostly of water, and each water molecule contains a hydrogen nucleus (proton) which becomes aligned in a magnetic field. An MRI scanner uses a strong magnetic field to align the proton ‘spins’, a radio frequency is then applied which causes the protons to ‘flip’ their spins before returning to their original alignment.
Protons in the different body tissues return to their normal spins at different rates so the MRI can distinguish between various types of tissue and identify any abnormalities. How the molecules ‘flip’ and return to their normal spin alignment are recorded and processed into an image.
MRI doesn’t use ionizing radiation and is increasingly being used during pregnancy with no side effects on the unborn child reported. However, there are risks associated with the use of MRI scanning and it isn’t recommended as a first stage diagnosis.
As strong magnets are used, any kind of metal implant, artificial joint, etc., can cause a hazard – they can be moved or heated up within the magnetic field. There have been several reported cases where patients with pacemakers have died through the use of MRI. The loud noise from the scanner also necessitates the need for ear protection.
One thing we do have to be aware of as medical professionals in a time of escalating medical costs and increasing demand is that we’re using the best resources available to meet the needs of our patients. That means a careful decision on the right medical imaging to be used for the patient and their potential diagnosis.