Venogram!

As discussed in last week's "pic of the week", laminitis or founder is a serious condition in horses that requires aggressive and frequent intervention by a veterinarian-farrier team. The radiographs below are those of a quarter horse gelding with moderate founder and approximately 10 degrees of coffin bone rotation. Although the gelding appears stable, he continues to be lame in the affected foot. Routine radiographic evaluation confirms that there has been no further rotation of the coffin bone but does not explain why the horse remains lame. 

The radiographs below are of the same horse AFTER injecting a radiopaque dye into one of the veins that removes blood from the equine foot. A tourniquet is applied at the level of the fetlock before the injection and this allows for the dye to pool within the venous vasculature. Radiographs are taken immediately after the injection and the current blood supply to the foot can be assessed. 

Careful evaluation of the above image suggests that the horse has adequate blood supply to the entire foot. This is evident by the extensive venous supply (white squiggly lines) that originate near the coronary band and essentially surround the entire foot. However, when the foot was imaged in a dorsal-palmar view (below), there appears to be a decline in blood supply to the inside of the foot versus the outside. The yellow arrows are pointing to the areas in question. Note the subjective decline in blood supply along the right side (inside) compared to the left side (outside)

Although these observations are not 100% definitive, they do suggest a reduction in blood supply to the medial aspect of the hoof. This information is important when considering the horses's prognosis and shoeing recommendations. Venograms can be easily performed in a stall-side setting but do require digital radiography and knowledge regarding the technique. The information gathered from these studies is considered an important piece of the puzzle regarding management of laminitis in the horse.