MRI

MRIs are the most exciting of the three medical imaging techniques discussed and have received the most recent developments. MRIs create very magnetic fields with superconducting wires, in which a person is placed. These scans are best used for doctors to see and trace the human brain and nervous system. MRIs deal with atomic physics, particularly spin, and a concept known as ‘relaxation time’. Relaxation times depend on the tissue being studied (i.e. brain matter, bone, muscle, etc…), and are responsible for the dark and bright spots we see on the generated images (see the black and white photos below) produced by MRI technology.

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A 3D image compiled by MRI slices	Another 3D image compiled by MRI slices

MRI technology is very expensive (the average cost per machine is about $1 000 000). For this reason, a doctor would not perform a MRI without first having the patient examined by a CT or PET scan. The waiting times for a MRI scan can range from 15 to 199 days in Ontario, where 90% of patients are served on average within 105 days. Interestingly enough, when asking to use a service, many hospitals will not inform a patient of other available services in the area, so be sure to do your research!

¹²	MRI technology can be used to receive images of the brain, joint tissue, stomach, pelvis, and insides of bones. MRIs can discover if a patient has cancer or other diseases. MRI technology is also useful for diagnosing trauma done to critical areas such as the spine, heart, or brain. The information obtained from the MRI can be used to conduct precise surgery in these areas of the body. Below is a sample image showing a slice of the brain produced by MRI technology.	¹²
A profile of a human head using MRI technology		A view through a human chest cavity
¹³ An actual MRI image (left) and animated comparison (right).

Click HERE! learn more about Magnetic Resonance Imaging from our expert medical physicist, Dr. Siobhan Ozard, Windsor Regional Cancer Centre.