Ultrasonography Can Replace CT Scans as the Initial Imaging Examination of Ureteral Calculi

OBJECTIVE: To study the feasibility of ultrasonography (US) as a replacement for CT during the diagnosis of ureteral calculi (UC). MATERIALS AND METHODS: Clinical and imaging data of patients with UC between January 2013 and December 2017 were retrospectively analyzed. According to the imaging method, patients were divided into 3 groups: Group A, CT alone; Group B, CT and US, Group C, US alone. Age, location, and the size of stones were compared among the groups. According to the maximum diameter (MD) measured by using CT in Group B, patients were subdivided into 3 groups (subgroup 1-3): MD 1.0 cm. The MD measured by US and CT were compared in the subgroups. RESULTS: A total of 1,289 patients with UC were admitted. The use of CT correlated with age (p = 0.000) and stone location (p = 0.004). The sensitivity and specificity of US were 71.3 and 100%. Positive US results correlated with stone size (p = 0.008), but not location (p = 0.861). The mean MDs of the calculi measured by US and CT: in subgroup 1:  0.80 ± 0.31 and 0.35 ± 0.05 cm (p = 0.000); in subgroup 2: 0.94 ± 0.32 and 0.72 ± 0.16 cm (p = 0.000); in subgroup 3: 1.75 ± 0.68 and 1.59 ± 0.52 cm (p = 0.094). CONCLUSIONS: US confirmed that UC do not require confirmatory CT. US can replace CT as the initial imaging examination of UC.