Value of detected hydronephrosis and hydroureter on ultrasound for detecting a ureteral stone: a retrospective study

To investigate the predictive value of hydronephrosis and hydroureter in the detection of ureteral stones using ultrasound, a total of 366 patients suffering from ureteral stones confirmed by ultrasound, computed tomography (CT) and their follow-up treatments were consecutively collected. All the included patients underwent systematic ultrasound scanning of the kidney and ureter. The hydronephrosis and hydroureter in each patient were measured using a digital caliper. Then, receiver operating characteristic (ROC) curve analysis was used to determine the optimal cutoff values for hydronephrosis and hydroureter to predict a ureteral stone’s location and size. The hydronephrosis, hydroureter, and stone size measurements showed good interobserver agreement (P < 0.001). Using the lower border of the sacroiliac joint as a demarcation point, we found larger widths of hydronephrosis and hydroureter in the proximal ureteral stone group than in the distal ureteral stone group (P < 0.001). Additionally, 10.9 mm and 5.9 mm were identified as optimal cutoff values for predicting a distal position (P < 0.001), with no significant difference in their predictive value (P > 0.05). Similar comparisons between groups based on size stratification revealed no significant difference in hydronephrosis between the > 5 mm group and the ≤ 5 mm group. However, the hydroureter was larger in the > 5 mm group than in the ≤ 5 mm group after identifying 6 mm as the best cutoff (P =0.004). In summary, the ultrasound measurement of hydronephrosis and hydroureter may predict the position and size of a possible ureteral stone in patients with colic symptoms.