Distal ureteral calculi: US follow-up

Abstract

Radiology. 2011; 260: 575-80 Purpose: To assess accuracy of ultrasonographic (US) follow-up of distal ureteral calculi by using computed tomography (CT) and conventional radiography (kidneys, ureters, and bladder) as reference standards. Materials and Methods: The study was approved by the Regional Ethics Committee, and written informed consent was obtained. One hundred fifty-eight patients with CT-diagnosed symptomatic ureteral calculi, for whom follow-up imaging was ordered, were enrolled from February 2006 to December 2008. Six were excluded, having not met study entry criteria, with 121 men (mean age, 49 years; range, 20-91 years) and 31 women (mean age, 44 years; range, 34-77 years) completing the protocol with adequate reference standard imaging. Targeted transabdominal US occurred coincidently with follow-up CT (n = 92) or radiography (n = 60), with US evaluation prospectively compared considering sensitivity and specificity. Statistical analysis was performed with a χ(2) test, t test, or paired t test, as appropriate. Results: Results of nine US examinations were nondiagnostic because of inadequate ureteral visualization, and among these, two cases showed residual distal calculi. Of the remaining 143 patients, 33 had residual distal calculi, all visualized with US. There was a single false-positive study, giving sensitivity, including nondiagnostic US examinations, of 94.3% (95% confidence interval [CI]: 80.8%, 99.3%) and specificity of 99.1% (95% CI: 95.3%, 100%). All calculi appeared hyperechoic with posterior acoustic shadowing. Additional diagnostic features included presence of a hypoechoic rim and Doppler twinkle artifact. Mean stone length was 7.2 mm ± 2.6 (stan-

Determining the Efficacy of Ultrasonography for the Detection of Ureteral Stone

“…Interestingly, Moesbergen et al 10 reported that bladder volume of 110 mL was required for adequate diagnostic testing. In our series, 42 distal stones were missed by US.…”

Imaging for urolithiasis

“…Ultrasound has been shown to be a good alternative to CT in follow-up imaging for patients diagnosed with distal ureteral stones and offered conservative management [45]. A prospective study examined patients who had an initial CT showing a distal ureteral stone and then follow-up imaging with ultrasound along with a CT or radiograph [45].…”

“…A prospective study examined patients who had an initial CT showing a distal ureteral stone and then follow-up imaging with ultrasound along with a CT or radiograph [45]. They found high sensitivity (94.3%) and specificity (99.1%) of ultrasound for detecting residual stones at follow-up.…”

Detection of Ureteral Stones With Transvaginal Sonography

“…3 Intravenous urography (IVU) and computed tomography (CT) are the standard imaging modalities to detect renal calculi. 3,6,7 These imaging modalities are not hindered by bowel gas or body habitus in evaluating for calculi, which makes them preferable to sonography. However, the use of intravenous radio-opaque contrast and the length of time required to perform an IVU make this imaging method impractical in an emergency setting.…”

“…1,7 CT can reliably detect urinary calculus regardless of size or location, but this method of imaging exposes the patient to radiation. 1,6 Such exposure to ionizing radiation should be avoided in particular in pregnant women and women of childbearing age. Because of these drawbacks, transvaginal sonography is a common alternative method used in the detection of urolithiasis.…”