Influence of patient positioning on sensitivity of mesenteric portography for detecting an anomalous portosystemic blood vessel in dogs: 34 cases (1997-2000).

Objective-To determine whether sensitivity of detecting an anomalous portosystemic blood vessel during operative mesenteric portography varied with patient positioning. Design-Retrospective study. Animals-34 dogs with a portosystemic shunt diagnosed via scintigraphy or surgery. Procedure-Portograms were evaluated for a portosystemic blood vessel. Sensitivity was calculated from results obtained with dogs in left lateral, right lateral, and dorsal recumbency and from results obtained with dogs in 2 or 3 positions. Differences in sensitivity among positions and between 2 examine rs were evaluated. Results-Sensitivity was 85, 91, and 100% in dorsal, right lateral, and left lateral recumbency, respectively. Sensitivity was lower in dorsal recumbency than in left lateral recumbency, although differences were not significant. There was no significant difference between sensitivity of results obtained in dorsal and right lateral recumbency or right lateral and left lateral recumbency. Sensitivity for combined right lateral and dorsal positions was 97%, which was better than that in dorsal recumbency alone, although the difference was not significant. Because sensitivity in left lateral recumbency was 100%, there was no need to evaluate the improvement obtained by combining the result of this position with the results of other positions. Conclusion and Clinical Relevance-Results of mesenteric portography varied with patient positioning. The optimal position varied among patients but left lateral recumbency may be better and dorsal recumbency worse. Sensitivity may be improved by performing the test with the patient in orthogonal recumbent positions.