Rapid localization of ureteral calculi in patients with renal colic by “ultrasonic ureteral crossing sign”

In this study, the term “ultrasonic ureteral crossing sign” is defined, and the diagnostic accuracy of this sign in the rapid localization of ureteral calculi is assessed. Between January 2017 and June 2018, 535 patients underwent ultrasound examination for suspected ureteral calculi. The “ultrasonic ureteral crossing sign” was classified as either positive or negative and correlated with the location of ureteral calculi. Of the 451 patients who were ultimately diagnosed with ureteral calculi, 263 patients had a positive sign, of which 258 patients had distal ureteral calculi, and 188 patients had a negative sign, of which 164 patients had proximal ureteral calculi. Eighteen stones were located in the ureter across the iliac vessels. For patients with a positive “ultrasonic ureteral crossing sign”, we observed a 91% sensitivity, 97% specificity, 98% PPV, 87% NPV, and AUC of 0.94 for distal ureteral calculi. For patients with a negative “ultrasonic ureteral crossing sign”, we observed a 97% sensitivity, 91% specificity, 87% PPV, 98% NPV, and AUC of 0.94 for proximal ureteral calculi. The “ultrasonic ureteral crossing sign” was found to accurately predict the location of ureteral calculi, significantly improve the efficiency of ultrasound examination, and provide a useful basis for follow-up treatment.