Comparison between ultrasound and noncontrast helical computed tomography for identification of acute ureterolithiasis in a teaching hospital setting

Abstract

CONTEXT AND OBJECTIVE: Recent studies have shown noncontrast computed tomography (NCT) to be more effective than ultrasound (US) for imaging acute ureterolithiasis. However, to our knowledge, there are few studies directly comparing these techniques in an emergency teaching hospital setting. The objectives of this study were to compare the diagnostic accuracy of US and NCT performed by senior radiology residents for diagnosing acute ureterolithiasis; and to assess interobserver agreement on tomography interpretations by residents and experienced abdominal radiologists. DESIGN AND SETTING: Prospective study of 52 consecutive patients, who underwent both US and NCT within an interval of eight hours, at Hospital São Paulo. METHODS: US scans were performed by senior residents and read by experienced radiologists. NCT scan images were read by senior residents, and subsequently by three abdominal radiologists. The interobserver variability was assessed using the kappa statistic. RESULTS: Ureteral calculi were found in 40 out of 52 patients (77%). US presented sensitivity of 22% and specificity of 100%. When collecting system dilatation was associated, US demonstrated 73% sensitivity, 82% specificity. The interobserver agreement in NCT analysis was very high with regard to identification of calculi, collecting system dilatation and stranding of perinephric fat. CONCLUSIONS: US has limited value for identifying ureteral calculi in comparison with NCT, even when collecting system dilatation is present. Residents and abdominal radiologists demonstrated excellent agreement rates for ureteral calculi, identification of collecting system dilatation and stranding of perinephric fat on NCT.

In young adults with a low body mass index ultrasonography is sufficient as a diagnostic tool for ureteric stones

“…[4] reported diagnostic accuracy rates of 83.2% for US and 85% for IVU and found that this increased to 96.8% when the two diagnostic methods were used in combination. An overview of the renal and ureteric stone detection rates using US reported in the studies referenced is shown in Table 2 [11–15,22,23,25].…”

“…The sensitivity and specifi city of US for the detection of ureteric calculi varies greatly in studies from 19 to 93% and 95 to 97%, respectively, while for unenhanced CT they are reported to be 91% and 95%, respectively [ 11,12 ] . Combined with collecting system dilatation, the sensitivity of US increased from 22% to 73% [ 13 ] and from 61% to 92% [ 14 ] and, combined with plain abdominal fi lm of kidney, ureter and bladder, it increased from 46% to 77% [ 15 ] . In the present study, the overall detection rate of US was high at 86.4%.…”

Focused Ultrasonic Propulsion of Kidney Stones: Review and Update of Preclinical Technology

“…[16][17][18][19][20][21][22] To determine the performance characteristics of the Verasonics imaging system, renal ultrasound images were obtained in nine human stone formers with 17 renal units. Ultrasound images of the upper, middle, lower poles, and the renal pelvis/UPJ were evaluated for stones by blinded reviewers and compared to recent CT imaging (within 60 days), which demonstrated a total of 27 stones with a mean size of 4.4 -3.3 mm.…”

B-mode Ultrasound Versus Color Doppler Twinkling Artifact in Detecting Kidney Stones

“…B-mode diagnostic ultrasonography is an alternative to CT without ionizing radiation; however, its adoption has been hindered by lower sensitivity (19%-93%) and specificity (84%-100%) for the detection of urinary calculi. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] Ultrasonography is also critically dependent on the sonographer. 18 Improvements in ultrasound hardware and signal processing might lead to better stone detection and increased use of this modality.…”