Imaging in Practice
M. J. Martinelli California Equine Orthopedics, Encinitas, CA, USA. Thephysical examination and gait analysis are the most important aspects of a musculoskeletal examination. However, knowing how to integrate and interpret diagnostic imaging modalities can significantly enhance both diagnostic potential and prognostic value.
The current generation of veterinarians relies extensively on evolving technology to provide a high quality of service to theirclients. Although this technology enhances many aspects of practice, diagnostic imaging seems to be the element that is changing most rapidly. In many ways, this is an exciting time to be an equine veterinarian. Suddenly, it is possible to visualize, diagnose, and treat conditions that were previously obscure or surmised to exist at best. Digital advances in radiology and ultrasound offer theability to enhance the images, which provides outstanding detail and better information. The recent availability of magnetic resonance imaging (MRI) in the practice setting has revolutionized the way clinicians can view some anatomical regions, particularly the foot and lower limb. However, with these exciting and innovative advancements in technology comes the added and inherent responsibly associatedwith interpreting the images accurately. Additionally and possibly more importantly, clinicians must learn to integrate the proper modalities at the correct time in the diagnostic process. Lameness is one of the most common problems facing equine veterinarians. The sore or lame horse, incapacitated and unable to perform, permeates every aspect of the equine profession from racing and showing tobackyard trail riding. Properly and effectively diagnosing and treating these musculoskeletal ailments can be a real challenge, even to the most experienced of clinicians. Part of the difficulty lies in the fact that both effective palpation and gait observation can be difficult to master. More importantly, these skills vary greatly between individuals. Even the interpretation of regional anesthesiacan be somewhat subjective, and therefore, prone to differences in opinion . Although deciphering the significance of the imaging modalities in relation to the musculoskeletal abnormality can be fraught with inconsistencies, it can often provide some concrete observations about the nature of the disease or injury. This is particularly true with radiology, nuclear scintigraphy, and ultrasound.2. Radiology
Radiology is an anatomical imaging modality most adept at determining the nature of the bone being examined. Classically, this has meant identifying fractures or osteoarthritis. In the case of the latter, radiology has been called a historical account of where the joint has been and not necessarily where it is currently. More meticulous and vigorous interpretation, however, canlead to earlier detection of disease processes in certain regions. In these cases, subtle differences in bone density, trabecular detail, and cortical thickness can be identified. Additionally, proper positioning and technique are imperative to such rigorous interpretation.
3. Nuclear Scintigraphy
Nuclear scintigraphy is classified as a metabolic imaging modality, because it relies on theinherent living properties of the tissue to produce an image. A bone seeking agent, usually methylene diphosphonate (MDP), is labeled with a radioactive compound (technetium 99m) to produce a radiopharmaceutical. This is injected intravenously; then, imaging commences. The vascular phase is carried out immediately on injection and images the radiopharmaceutical as it courses through the blood vessels....