Effect of a static magnetic field on blood flow to the metacarpus in horses

Objective-To determine the effect of a static magnetic field on relative bl ood flow to the metacarpus of horses. Design-Randomized controlled clinical trial. Animals-6 healthy adult horses. Procedure-Red blood cells were radiolabeled in vivo by administration of te chnetium Tc 99m (pyro- and trimeta-) phosphates, and scintigraphic images w ere obtained 30 minutes later. A magnetic wrap that emitted a static magnet ic field was applied to 1 metacarpus and a control wrap was applied to the contralateral metacarpus. Forty-eight hours later, the wraps were removed, and scintigraphy was repeated. Relative perfusion ratios were calculated by dividing mean count per pixel for the portion of the metacarpus under the wrap by mean count per pixel for a portion of the distal aspect of the ante brachium that was not in the magnetic field. Results-The difference between the relative perfusion ratio prior to applic ation of the wrap and the ratio after application of the wrap for limbs tha t received the magnetic wrap was not significantly different from the diffe rence in ratio for limbs that received the control wrap. Conclusions and Clinical Relevance-Results suggest that in horses, the stat ic magnetic field associated with application of commercially available mag netic wraps for 48 hours does not increase blood flow to the portion of the metacarpus underneath the wrap.