In a retrospective study, results of preoperative ultrasonography were compared with actual findings on exploratory abdominal surgery. Ultrasonography must have been done within 48 hours of the surgery. Surgical findings were classified as "primary" or "secondary." Primary lesions were defined as the main surgical finding (eg, ruptured gallbladder), and secondary findings were categorized as any other finding (eg, peritonitis associated with ruptured gallbladder). The findings of the surgical report were compared with those of the ultrasound report. There were 19 cats and 81 dogs in the study. The animals were divided into body groupings: cats (n = 19), small dogs (n = 17), medium-sized dogs (n = 47), and large dogs (n = 17). Surgical reports noted 100 primary lesions and 67 secondary lesions. The primary surgical finding was not identified in 24 animals, and secondary surgical findings were not identified in an additional 11 animals. The most common primary surgical findings were peritonitis (n = 28), splenic/liver masses (n = 30), and intestinal obstruction (n = 14). Lesions missed by ultrasonography tended to be associated with the gastrointestinal tract. Ulcerations, perforations, and ruptures of the gastrointestinal tract were most often missed (P = 0.04), along with organomegaly (P = 0.06). Intestinal foreign bodies were missed in 5 animals (not a statistically significant number). Overall, ultrasound and exploratory surgery findings were in agreement in 64% of animals, but major discrepancies were found in 25% of animals.

COMMENTARY: This study reinforces the value of abdominal ultrasound as a noninvasive screening tool for helping detect lesions amenable to surgery. Ulcerations, perforations, and ruptures of the gastrointestinal tract were most frequently missed by ultrasound examination. Peritoneal free fluid is an important indicator of potential gastrointestinal pathology for ultrasonographers, and early in a disease process, it may be hard to find. If time allows, performing ultrasound rechecks 12 to 24 hours apart may detect increases of fluid accumulation suggesting pathology. Overall these findings indicate that abdominal ultrasound is a useful presurgical screening test; however, to maximize ultrasound capabilities, especially when gastrointestinal disease is suspected, serial examinations should be used. -- Kristy Broaddus, DVM, Diplomate ACVS

Comparison of the results of abdominal ultrasonography and exploratory laparotomy in the dog and cat. Pastore GE, Lamb CR, Lipscomb V. JAAHA 43:264-269, 2007.