Evaluating the diagnostic accuracy of point-of-care ultrasound for cholelithiasis and cholecystitis in a canadian emergency department

Objectives Cholelithiasis and cholecystitis are common conditions that frequently require patients to come to the Emergency Department (ED) and undergo diagnostic imaging. The purpose of this study was to evaluate the test characteristics of emergency physician performed point-of-care ultrasound (POCUS) to diagnose cholelithiasis and cholecystitis in a Canadian ED. Methods A health records review was performed on all ED patients > 17 years of age for whom POCUS was performed to diagnose cholelithiasis and cholecystitis in a Canadian academic ED over a 5-year period. The sensitivity, specificity, predictive values, and likelihood ratios were calculated. The gold standard used for diagnosis was pathology, laparoscopy, radiology-performed comprehensive ultrasonography, followed by computed tomography scans. Results A total of 577 patients were included in the study. The sensitivity and specificity of POCUS to diagnose cholelithiasis was 95.2% (95% CI 91.1-97.8%) and 93.1% (95% CI 90.1-95.4%). The positive and negative likelihood ratios for POCUS to diagnose cholelithiasis were found to be 14 and 0.05; the negative predictive value was 97.6% (95% CI 95.5-98.7%). The sensitivity and specificity of POCUS to diagnose cholecystitis was 67.1% (95% CI 54.9-77.9%) and 97.6% (95% CI 95.9-98.8%). The positive and negative likelihood ratios for POCUS to diagnose cholecystitis were found to be 28 and 0.34; the negative predictive value was 95.6% (95% CI 93.9-96.8%). Conclusion POCUS is reliable for the diagnosis of cholelithiasis and for ruling in cholecystitis. In cases where POCUS is negative or indeterminate for cholecystitis, further imaging should be obtained as clinical suspicion warrants.