bellequine.co.uk - INDICATIONS FOR BONE SCANS

INDICATIONS FOR BONE SCANS

• Lameness that cannot be blocked.

• Lameness that cannot be localised and/or multiple limb / shifting lameness.

• Lameness that can be blocked but no radiographic changes are seen.

• An uncooperative horse where it would be dangerous to attempt regional analgesia.

• Back and proximal limb problems.

The advantage of bone scans over radiography is that it provides a physiological or metabolic assessment of the bone in contrast to an anatomic or morphological assessment. As a result nuclear bone imaging is more sensitive to localising and quantifying dynamic bone change before these changes may be seen on radiographs. However this may also result in some false positive results being detected and any findings should be interpreted with clinical symptoms and other diagnostic procedures.

The inflammation that occurs as a result of injection of local anesthetics in any pre-emptive diagnostic work-up will only interfere with scintigraphic findings in the vascular and soft tissue phases. As such it is advised that vascular or soft tissue scintigraphy is delayed for between two to three weeks after injection of local anaesthetic. For the most part local anaesthesia does not affect the results of bone phase scintigraphy with perhaps the exception of intra-articular injection into the intertarsal joints where they may be some influence on up-take the bone phase of scintigraphy.

As a general rule the overall uptake in younger horses is better than older horses and in thoroughbreds and light breeds is better than in heavy draft breeds or warmbloods. There may be individual variation with lower uptake in one limb compared to the contra-lateral limb or lower uptake in both limbs below the carpus or the hock. We bandaged the limbs to try and compensate for this and request that the limbs are bandage overnight prior to admission.

It should be borne in mind that about 50% of chronic lameness cases will have negative scintigraphic findings due to lack of sufficient bone turnover at the site of pathology.