Preoperative parameters (signalment, digital radiography, urinalysis, urine microbiological culture) and novel algorithm improve prediction of canine urocystolith composition

OBJECTIVE

To determine the accuracy of 4 preoperative parameters (signalment, urinalysis, urine microbiological culture, and digital radiography) in predicting urocystolith composition, compare accuracy between evaluators of varying clinical experience and a mobile application, and propose a novel algorithm to improve accuracy.

ANIMALS

175 client-owned dogs with quantitative analyses of urocystoliths between January 1, 2012, and July 31, 2020.

METHODS

Prospective experimental study. Canine urocystolith cases were randomly presented to 6 blinded "stone evaluators" (rotating interns, radiologists, internists) in 3 rounds, each separated by 2 weeks: case data alone, case data with a urolith teaching lecture, and case data with a novel algorithm. Case data were also entered into the Minnesota Urolith Center mobile application. Prediction accuracy was determined by comparison to quantitative laboratory stone analysis results.

RESULTS

Prediction accuracy of evaluators varied with experience when shown case data alone (accuracy, 57% to 82%) but improved with a teaching lecture (accuracy, 76% to 89%) and further improved with a novel algorithm (accuracy, 93% to 96%). Mixed stone compositions were the most incorrectly predicted type. Mobile application accuracy was 74%.

CLINICAL RELEVANCE

Use of the 4 preoperative parameters resulted in variable accuracy of urocystolith composition predictions among evaluators. The proposed novel algorithm improves accuracy for all clinicians, surpassing accuracy of the mobile application, and may help guide patient management.

Computed tomographic, magnetic resonance imaging, and ultrasonographic characteristics of retrobulbar meningiomas in 15 dogs

Meningioma is the most common tumor of the cranium in dogs and an important differential diagnosis for a potentially treatable disease that can be found in the periorbital tissues. The objective of this retrospective, case series study was to describe the CT, MRI, and US characteristics of confirmed retrobulbar meningiomas in a group of dogs. Medical records from multiple institutions were searched for canine patients with CT, MRI, and/or US imaging of a cytologically or histologically confirmed retrobulbar meningioma. Fifteen dogs met the inclusion criteria. Retrobulbar meningiomas typically appeared as a relatively well-defined conical to ovoid mass within the retrobulbar space, most often along the optic nerve and expanding the extraocular muscle cone. On CT, masses were predominantly soft tissue attenuating and variably heterogeneously contrast enhancing. While MRI features were variable, moderate to marked contrast enhancement was seen in all cases. Many of the tumors had evidence of partial mineralization, best appreciated on CT in nine patients, but also suspected based on susceptibility artifacts in three MRI cases, one of which was confirmed on CT. Regional osteolysis was a rare finding, noted in three cases, but was often accompanied by cranial cavity extension (2/3). Cranial cavity extension was also seen in the absence of regional osteolysis, identified in a total of six patients. On US, masses were echogenic and compressed the globe. The findings were consistent with previous gross and histologic descriptions and supported prioritizing retrobulbar meningioma as a differential diagnosis for dogs with the described imaging characteristics.

Ultrasonographic evaluation of cholecystoduodenostomy sites in six cats

CASE SERIES SUMMARY

This case series describes the postoperative ultrasonographic findings in six cats that underwent a cholecystoduodenostomy as treatment for extrahepatic biliary obstruction. The surgery site was identified in all six cats, most often within the right cranial abdomen as a thick-walled gall bladder, with a broad-based connection to the descending duodenum. Postoperatively, the biliary tree often remained distended, similar to its preoperative appearance. Recurrent extrahepatic biliary obstruction was suspected in three cats with worsening hyperbilirubinemia. Common bile duct distension was progressive in one of these cats and unchanged in another, but improved in the third. Intrahepatic bile duct distension resolved in one cat following surgery but reappeared with suspected recurrent biliary obstruction. In two cats, progressive echogenic biliary contents were associated with locally aggressive cholangiocarcinoma. Our findings suggest that in cats with cholecystoduodenostomy and progressive increases in hyperbilirubinemia following surgery, progressive or recurrent biliary distension and/or progressive echogenic biliary contents should prompt further investigation.

RELEVANCE AND NOVEL INFORMATION

Biliary diversion surgery in cats is associated with high morbidity and mortality. The ultrasonographic appearance of a postoperative cholecystoduodenostomy site has not been described, making differentiation of the expected appearance from postoperative abnormalities difficult. The goal of this study was to determine the expected ultrasonographic appearance, in order to assist in managing cats with recurrent, persistent or worsening clinical signs and biochemical abnormalities following surgery.