Diagnostic imaging is the process of using various technologies to
view structures and/or processes not discernible from the outside of
the horse. These technologies include x-rays and CT scans,
ultrasound, MRI, nuclear scintigraphy (nuclear scan or bone scan),
and thermography. Since CT, MRI and nuclear scintigraphy are
hospital procedures and are not currently suitable for use in the field,
we commonly employ X-rays and ultrasound, depending on whether
we need to visualize predominantly soft tissue or bony structures.
X-rays are most useful for evaluating bony structures, whereas
ultrasound is better suited for examining soft tissue structures.
However, there are several instances where this rule does not apply.
In some cases, ultrasound has been better able to identify small bony
chip fractures than x-rays, and occasionally x-rays will identify a soft
Disorders commonly diagnosed with x-rays include arthritis of various
joints, coffin bone rotation due to laminitis, tooth root abscesses, and
Ultrasound can reveal injuries and inflammation of tendons and
ligaments, soft tissue abscesses, and foreign bodies. In horses,
ultrasound is also very commonly used to evaluate the mare's
reproductive tract. It can even be used to look at the inner structures
of the horse's eye.
The images seen to the left:
Middle image: An x-ray of a horse's hock.
Bottom image: A cross sectional view with ultrasound of the tendons
and ligaments of the lower limb. The skin is at the top of the image,
cannon bone at the bottom.