A bone scan allows us to look at the whole skeleton of a horse. This image shows uptake in a horse's back (yellow arrow).
This is a bone scan image of a normal horse's pelvis.
Nuclear Scintigraphy or “bone scan” as it is commonly called, is a technology taken directly from the human medical field. A safe, low-dose radioactive isotope is injected intravenously in the horse. The isotope has an affinity for actively remodeling bone, which indicates bone inflammation and/or injury. The bone scanner then detects the amount of isotope present in the bone and makes an image of the region being evaluated.
A bone scan is indicated when the complaint is related to poor performance or when the lameness is difficult to diagnose due to the horse not being visibly and/or consistently lame.
One of the main benefits of scintigraphy is the higher degree of sensitivity when compared to radiographs. It is common for a problem area to appear normal on a radiograph, but to show activity on a bone scan image. Another benefit of performing a bone scan is that virtually every bone in the body can be imaged without the need for general anesthesia. This is particularly helpful for identifying bone related problems in the upper limbs, head, neck, back and pelvic regions of the horse.
In order to conduct the bone scan, the horse is required to stay in the hospital for at least 24 hours after the time of injection (they are radioactive). For this reason, horses scheduled for bone scans must arrive early (before 8:30am) on the day of the scan, and stay in the clinic overnight. The actual scan is conducted 2 hours after the isotope is injected, starting with distal limbs and ending with axial skeleton. Frequently, any follow-up work is done the following day based on the bone scan uptake.
These images show moderate - severe focal uptake at the region of the accessory carpal bone. After radiographs of this region were taken it was discovered that this bone was fractured.