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 portos ystemic blood vessel during operative mesenteric portography varied with pa tient positioning. Design-Retrospective study. Animals-34 dogs with a portosystemic shunt diagnosed via scintigraphy or su rgery. Procedure-Portograms were evaluated for a portosystemic blood vessel. Sensi tivity was calculated from results obtained with dogs in left lateral, righ t lateral, and dorsal recumbency and from results obtained with dogs in 2 o r 3 positions. Differences in sensitivity among positions and between 2 exa mine rs were evaluated. Results-Sensitivity was 85, 91, and 100% in dorsal, right lateral, and left lateral recumbency, respectively. Sensitivity was lower in dorsal recumben cy than in left lateral recumbency, although differences were not significa nt. There was no significant difference between sensitivity of results obta ined in dorsal and right lateral recumbency or right lateral and left later al recumbency. Sensitivity for combined right lateral and dorsal positions was 97%, which was better than that in dorsal recumbency alone, although th e difference was not significant. Because sensitivity in left lateral recum bency was 100%, there was no need to evaluate the improvement obtained by c ombining 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 le ft lateral recumbency may be better and dorsal recumbency worse. Sensitivit y may be improved by performing the test with the patient in orthogonal rec umbent positions.