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- Author or Editor: Phillip F. Steyn x
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Abstract
Objective—To determine the effect of a static magnetic field on relative blood 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 technetium Tc 99m (pyro- and trimeta-) phosphates, and scintigraphic images were obtained 30 minutes later. A magnetic wrap that emitted a static magnetic 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 antebrachium that was not in the magnetic field.
Results—The difference between the relative perfusion ratio prior to application of the wrap and the ratio after application of the wrap for limbs that received the magnetic wrap was not significantly different from the difference in ratio for limbs that received the control wrap.
Conclusions and Clinical Relevance—Results suggest that in horses, the static magnetic field associated with application of commercially available magnetic wraps for 48 hours does not increase blood flow to the portion of the metacarpus underneath the wrap.(J Am Vet Med Assoc 2000;217:874–877)
Abstract
Objective—To evaluate use of technetium Tc 99m disodium hydroxymethylene diphosphonate (99m-Tc- HDP) for assessing fracture healing and 99m-Tc-HDP and technetium Tc 99m ciprofloxacin (99m-Tc-CIPRO) for early diagnosis of osteomyelitis in rabbits.
Animals—32 skeletally mature New Zealand White rabbits.
Procedure—A femoral fracture defect stabilized with bone plates and cortical screws was used. Scintigraphy was performed 4, 8, 12, and 16 weeks after surgery. The 99m-Tc-CIPRO scan was performed 48 hours after the 99m-Tc-HDP scan. The uptake ratio of the experimental limb to the normal limb was calculated by use of multiple regions of interest. Results of radiography performed to determine external callus and lysis grade and percentage defect ossification at 16 weeks were compared with scintigraphy results.
Results—Infected fractures had a higher uptake ratio for 99m-Tc-HDP and 99m-Tc-CIPRO than noninfected fractures. Infected fractures could be differentiated from noninfected fractures late in healing by use of 99m-Tc-HDP. Although 99m-Tc-CIPRO was better than 99m-Tc-HDP for identifying infection, there was a high incidence of false positive and negative results with 99m-Tc-CIPRO. There was an association between 99m-Tc-HDP uptake ratio and callus formation and a good correlation between 99m-Tc-HDP uptake ratio and defect ossification after 4 weeks.
Conclusions and Clinical Relevance—99m-Tc-HDP and 99m-Tc-CIPRO may be useful for diagnosing osteomyelitis late in fracture healing; however, false positive and false negative results occur. Technetium Tc 99m disodium hydroxymethylene diphosphonate may be useful for evaluating fracture healing. ( Am J Vet Res 2003;64:736–745)