Correlation of ultrasonographic findings with surgical, portographic, and necropsy findings in dogs and cats with portosystemic shunts: 63 cases (1987-1993).

Results of abdominal ultrasonography in 63 dogs and cats with suspected congenital portosystemic shunts (PSS) were compared with surgical, portographic, and necropsy findings. True-positive ultrasonographic results were found in 33 animals, and 2 animals had false-positive results for detection of single extrahepatic PSS. In 4 animals, results were true negative and in 8 animals, were false-negative for detection of extrahepatic PSS. The false-negative rate decreased substantially with operator experience. The sensitivity of ultrasonography for detection of extrahepatic PSS in these animals was 80.5%, and the specificity was 66.7%. In 5 other animals, ultrasonographic examination was strongly suggestive of the existence of a shunt, but the vessel could not be definitively imaged. All 5 animals had single extrahepatic shunts. Eleven animals had true-positive results for detection of intrahepatic PSS. One animal had false-positive ultrasonographic results for intrahepatic PSS, but an extrahepatic shunt was diagnosed at surgery. The sensitivity of ultrasonography for detection of intrahepatic PSS was 100%.