Musculoskeletal imaging in the cat: what's normal? What's abnormal?

PRACTICAL RELEVANCE: Despite the increasing availability of ultrasonography, computed tomography and magnetic resonance imaging (MRI), radiography remains the primary imaging modality for the assessment of feline musculoskeletal disease in practice. In many respects, having a more feline-focused approach to radiography will reward the clinician with better quality images and, hence, a greater likelihood of a correct diagnosis. CLINICAL CHALLENGES: Correct interpretation of radiographic films requires familiarity with some of the unique aspects of normal feline skeletal anatomy. For optimal patient management, the clinician also needs an appreciation of the distinct advantages of advanced imaging modalities in certain circumstances, in particular for head trauma patients. EQUIPMENT: When considering what equipment is most suitable for musculoskeletal imaging, the small size of our feline patients means that image resolution is of primary importance. Choosing an x-ray system (film-screen or digital) that offers more detail, and selecting ultrasound probes of a higher frequency than would be used on larger canine patients, will go some way to improving the diagnostic yield of any feline imaging study. If there is the option of referral for MRI, and a choice between high-field and low-field MRI systems for the feline patient, a high-field system will always provide more detail. AUDIENCE: This review, drawing on the author's experience and established imaging and anatomical principles, aims to assist general veterinary practitioners in their approach to feline musculoskeletal imaging. It provides an overview of the imaging choices and techniques for different regions of the body, and gives examples of normal anatomy that is peculiar to the cat.