Diagnostic Accuracy of Ultrasound to Predict the Location of Solitary Hepatic Masses in Dogs.

Abstract

OBJECTIVE: To determine the sensitivity, specificity, and predictive value of ultrasonography for localizing hepatic masses in dogs and to identify patient factors associated with diagnostic accuracy. STUDY DESIGN: Retrospective cross-sectional study. ANIMALS: Client-owned dogs (n = 137). METHODS: Medical records of dogs diagnosed with a solitary hepatic mass on abdominal ultrasound and confirmed by laparotomy or laparoscopy were reviewed. Location of the mass predicted by ultrasound was compared to mass location identified at surgery. Ultrasound exams were performed by or under the supervision of a board certified radiologist. Sensitivity, specificity, and positive predictive values were calculated. Patient factors associated with accurate localization were identified using logistic regression. RESULTS: Ultrasound correctly localized liver masses in 71/137 dogs (51.8%). The sensitivity of ultrasound localization was 55% for left and right division masses and 29% for central division masses. The specificity was 98% for left division masses, 87% for central division masses, and 89% for right division masses. Correct localization was 3.2 times more likely when the mass arose from the right or left division compared to the central division (odds ratio [OR] 3.2; 95% confidence intervals [CI] 1.1, 9.0; P = .030). Correct localization was significantly less likely when diffuse or multifocal hepatic disease was present (OR 0.32; 95% CI 0.15, 0.70; P = .004). CONCLUSION: Ultrasound was specific but not sensitive for localizing hepatic masses, and localization accuracy was influenced by mass location and the presence of concurrent liver pathology. These findings should be taken into consideration by veterinary surgeons using ultrasound examination to guide patient treatment and surgical planning.