The Standing MRI Stands Above the Rest
By Laura McCormick
Difficult-to-diagnose unsoundness issues with our sport horses are among the many challenges our veterinarians face. Thanks to the latest advancement in diagnostics with the standing MRI, getting to the source of the problem has never before been more accurate and safer for our equine partners.
M
agnetic Resonance Imaging (MRI) was first used in veterinary medicine in the 1990s, mostly for small animal patients under general
anesthesia. The innovation of the high field magnet was a breakthrough in medical technology for ani- mals large and small. It wasn’t long before equine veterinarians were using MRI technology to produce diagnostic images the equine community had never seen before. However, the risks associated with anesthetizing a horse for diagnostic purposes led doctors to develop a safer way to acquire these valuable images. The development of the low field magnet in 2002, by Dr.
Nick Bolas and his associates at Hallmarq Veterinary Imag- ing, opened new doors in equine diagnostics. In the last few years alone, magnetic resonance (MR) scanning capa- bilities have popped up in clinics everywhere. Halmarq is a leader in the field, developing the first standing equine MRI machine. There are now more than 62 “magnets” installed around the world. The biggest advantage? Your horse no longer needs to be anesthetized for the procedure, but can remain awake and standing while the images are collected. Currently, there are 14 standing units installed in the United Kingdom and 20 in the United States and Canada. As of January 2013, more than 33,000 horses have been scanned in reference to lameness evaluations by this cutting edge equipment. Operators, veterinarians, technicians and ra- diologists have been very successful in working towards understanding different techniques in acquiring images as well as the benefits and limitations of using MRI in standing, equine patients. Never before has a modality been able to provide vets with such a detailed picture of both soft tissue and bone. The standing MRI is used as a diagnostic tool to identify the cause of lameness in the foot, pastern and fetlock. Although many veterinarians are still learning about the field, those who are involved in clinical use of the MRI are working to help educate other veterinarians, as well as horse owners, rid- ers and trainers, about its purpose and accuracy when used to determine injuries inside tissue and bone that we cannot see with radiographs or ultrasound images.
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“The major advantage is that it can see things you can- not see by any other technique,” says Dr. Nick Bolas, director of Hallmarq Veterinary Imaging and inventor of the standing MRI. By collecting 400-500 images of the area, radiologists have a number of ways to look at soft tissue and bone in order to determine an accurate
diagnosis. “A competitive sport horse will collect damage that will show up on an MR image and it is up to the radiolo- gist reading the images to find the lesions, describe them, and also decide which are new and which are old,” Dr. Bolas explains. “They will make their decision based on 20-30 of those images, select the best ones to describe the diagnosis, and create a report for the veterinarian and owner with the images they have selected.” Because the slices are aligned, interference is eliminated and the person reading the exam can see the specifics of the area in the image.
How It Works The MR image is created by the magnetism between the
nuclei of hydrogen atoms and the external magnet in the machine. The positively charged protons and electrically neutral neutrons are “spinning” creating its own magnetic field. Hydrogen, which is found in both water molecules
TOP OF PAGE: A sedated horse in the standing MRI machine. ABOVE: The horse’s foot being imaged in the standing MRI machine.
Laura McCormick
Laura McCormick
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