Clinical Applications of Digital Venography

Digital venography is a form of contrast angiography that is used to define the vasculature of the digit. The technique is relatively simple and can be performed stall-side using standard radiographic equipment, so it can be used to evaluate a variety of clinical conditions of the equine foot. However, it is important to become familiar with the vascular patterns noted in the healthy foot to make full use of the technique in the diagnosis and management of the diseased foot. In short, venous compromise or occlusion results in a reduction or absence of contrast in the affected area. Causes of venous compromise include an alteration of load within the foot, (compression) space-occupying masses such as a keratoma, and thrombosis. Most often, venography is used to supplement routine radiography in evaluating the laminitic patient. Alterations in the contrast pattern are evident before radiographically discernible displacement of the distal phalanx, the extent of the vascular alteration being determined by the severity of pathology in the suspension apparatus of the distal phalanx (ie, the dermal-epidermal bond). Information gained from the venogram can greatly assist with treatment decisions, and serial venography is valuable in monitoring response to treatment and making modifications accordingly. So, although both the procedure and interpretation require skill development which is gained with experience, veterinarians are encouraged to use digital venography routinely in evaluating and managing the laminitic patient as well as in patients presenting with foot lameness of undetermined cause.