Scintigraphic evaluation of 99mTc-methylene diphosphonate uptake in the navicular area of horses with lameness isolated to the foot by anesthesia of the palmar digital nerves.

The research article investigates the distribution and intensity of 99mTc-methylene diphosphonate (99mTc-MDP) uptake in the navicular bone area in horses with lameness isolated to the foot, and how scintigraphy can aid in diagnosing this condition.

Methodology

• The study conducted was a prospective, case-controlled study with two groups; a group of 7 horses showing clinical signs of navicular syndrome and a control group of 7 healthy horses.
• Scintigraphic imaging was performed on the palmar view of the foot at multiple time intervals ranging from 7 minutes to 4 hours post-injection of 99mTc-MDP.
• The intensity of uptake in the navicular area was evaluated from the images, and the image density in the navicular area was compared to the mean image density in the distal phalangeal area.
• The researchers also assigned subjective scores to the navicular area intensity on the scintigraphic images based on their intensity.
• The density ratios and mean scores were statistically analyzed using a three-way ANOVA.

Findings

• The analysis showed that the navicular-to-distal phalangeal density ratio for the group of affected horses was significantly higher than that for the control group.
• The subjective score for the affected horses, when evaluating palmar views only and palmar and lateral view pairs together, was also significantly higher than the scores for the control group.
• The researchers found that the scintigraphic images acquired 1 hour after injection were as effective at differentiating between affected and control horses as images obtained between 2 to 4 hours after the injection, which suggests that this could be an optimum time for imaging.

Conclusion

• The study found that a substantial number of horses suffering from palmar foot pain demonstrated increased scintigraphic uptake within the navicular bone 1 to 4 hours after injection of 99mTc-MDP.
• The researchers concluded that a combination of scintigraphic images from both lateral and palmar views obtained between 1 to 4 hours post 99mTc-MDP injection can be useful in diagnosing navicular bone involvement in horses suffering from foot lameness.