Ultrasound accuracy for finding ureter blockages in cats

Abstract

OBJECTIVE To assess the utility of ultrasonography to detect the cause and location of ureteral obstruction in cats and to identify factors associated with agreement between ultrasonographic and surgical findings. STUDY DESIGN Retrospective case series. ANIMALS 71 cats. PROCEDURES Medical records were searched to identify cats that had ureteral obstruction diagnosed ultrasonographically and that subsequently underwent exploratory laparotomy. Patient signalment, ultrasonographic findings, interventions performed, and surgical findings were recorded. Cause and location of ureteral obstruction as assessed by ultrasonography were compared with surgical findings. Sensitivity, specificity, and positive predictive value of ultrasonography for detection of ureteroliths and strictures were calculated. Statistical analysis was performed to identify factors associated with agreement between ultrasonographic and surgical findings. RESULTS There was significant, moderate agreement between ultrasonographic and surgical findings for the cause and location of ureteral obstruction. Signalment variables, ureter affected (left vs right), and presence of retroperitoneal effusion were not associated with this agreement. Sensitivity was 98% and 44%, specificity was 96% and 98%, and positive predictive value was 98% and 88% for detection of ureteroliths and strictures, respectively, by ultrasonography. CONCLUSIONS AND CLINICAL RELEVANCE Ultrasonography was highly sensitive for detection of ureteroliths that caused ureteral obstruction but was considerably less sensitive for detection of ureteral strictures in the study population. Future prospective studies are needed to determine the role of advanced imaging in assessing cats with ureteral abnormalities. (J Am Vet Med Assoc 2019;254:710-715).