The Rossmore Veterinary Centre is pleased to announce that it has just installed one of the few Veterinary MR in Australia. The unit is now operational for the diagnosis and treatment of small animal veterinary medicine.
Now with it’s own Vet MR, the Rossmore Veterinary Centre can offer this advanced imaging safely and reliably to investigate and treat cases with the minimum of delay. In most cases the MR procedure is being performed on the same day of the initial consultation.
In the past few years, Magnetic Resonance Imaging (MRI) has grown to become the imaging modality of choice to view the inside of the body for anatomy and disease.
MRI encompasses the use of magnetism, radio waves and computers to create an image. Unlike X-Rays and CT scans, MRI has no radiation, and therefore has no proven side effects. This piece of equipment is an actual magnet that has been mined from the earth. MRI magnets vary in magnetic field strengths measured in “Tesla”. Usual MRI system magnetic field strengths vary from 0.2 to 1.5 Tesla. The one we use is a 0.2 Tesla system. The magnetic field is needed to move and align the hydrogen protons in the patient’s body for detection by the system.
Magnets are constantly on and the magnetic pull can reach up to thirty thousand times the earth’s gravitational pull. Inside the scanner, there are three magnetic gradients, which produce the loud pounding noise that can be often heard.
The area being imaged must be directly in the centre of the MRI scanner. Once the magnetic fields align the hydrogen protons in the body, radio frequencies are introduced into the body.
The radio frequencies are turned on and off, so the hydrogen protons move. When the hydrogen protons resonate back in to position, they create a radio signal of their own. The signal sent by the tissues differs depending on the different tissues being examined. Bone gives a different signal than muscle, and muscle gives a different signal than fat, and disease gives a different signal from normal tissue. The signal is received by he coil (antenna) and transported to the computer, which analyses the data, and creates a video image. There are many different coils because they are designed to fit certain body parts. Intravenous contrast material can be used for enhancing certain body parts.
Each MRI exam is composed of 2-6 smaller exams called sequences or series covering up to 10cm. The different sequences are needed to cover different angles and to control the different density and contrast characteristics of tissues. MRI procedures are painless and take between 45-60 minutes, with additional time required for sedation and recovery.