Objective: To compare the accuracy of B-Mode US and color Doppler twinkling artifact for detecting residual stone after Percutaneous Nephrolithotomy (PCNL) with Non-contrast CT (NCCT) as the standard diagnostic. Material & methods: In this prospective study, 30 patients who underwent Percutaneous Nephrolithotomy (PCNL) were examined with US and NCCT. In US, echogenicity and posterior-shadow (PS) parameters were evaluated and compared with color-Doppler ultrasonography (CDUS) twinkling artifact and NCCT signs. The results then analyzed statistically with Kappa and McNemar tests. Results: More positive residual stone results with color Doppler twinkling artifact in 14 patients than B-Mode US in 11. NCCT detected 17 residual stone with the most location in inferior calyx. (n=10, 58.8%). The sensitivity, specificity and difference positive-negative likehood ratio of B-Mode US were 64.7%, 92.3% and 8.02, both Kappa test was significant (p=0.125) and McNemar tests was significant (p=0.002). The color Doppler twinkling artifact has 82.3%, 92.3%, and 10.5 for sensitivity, specificity and difference positive-negative likehood ratio, the Kappa test was significant (p=0.00), McNemar test was not significant (p=1.00). Conclusion: Color Doppler twinkling artifact was valid, highly sensitive and accuracy better than B-mode US in detecting residual stone after PCNL procedure.
Percutaneous nephrolithotomy, residual stone, B-mode US, color Doppler US, twinkling artifact, non-contrast CT
Abdelhafez MF. Residual stones after percutaneous nephrolithotomy. Med Surg Urol. 2013; 2(2): 1–3.
Ganpule A, Desai M. Fate of residual stone after percutaneous nephrolithotomy: A critical analysis. J Endourol. 2009; 23(3): 399–403.
Ahmad SK, Abdalah MM. The diagnostic value of the twinkle sign in color Doppler imaging of urinary stones. The Egyptian Journal of Radiology and Nuclear Medicine. 2014; 45: 569–74.
Liu W, Esler SJ, Kenny BJ. Low-dose non enhanced helical CT of renal colic: Assessment of ureteric stone detection and measurement of effective dose equivalent. Radiology. 2000; 215: 51–4.
Abu-Zidan FM, Hefny AF, Corr P. Clinical ultrasound physics. J Emerg Trauma Shock. 2011; 4(4): 501–3.
Rahmouni A, Bargoin R, Herment A, Bargoin N, Vasile N. Color Doppler twinkling artifact in hyperechoic regions. Radiology. 1996; 199: 269–71.
Ozdedeli K, Cek M. Residual fragments after percutaneous nephrolithotomy. Balkan Med J. 2012; 29: 230–5.
Zhu Z, Wang S, Xi Q. Logistic regression model for predicting stone-free rate after minimally invasive percutaneous nephrolithotomy. Urology. 2011; 78(1): 32–6.
El-Nahas AR, Eraky I, Shokeir AA. Factors affecting stone-free rate and complications of percutaneous nephrolithotomy for treatment of staghorn stone. Urology. 2012; 79(6): 1236–41.
Fowler KAB, Locken JA, Duchesne JH. US for detecting renal calculi with non enhanced CT as a reference standard. Radiology. 2002; 222: 109–13
Ulusan S, Koc Z, Tokmak N. Accuracy of sonography for detecting renal stone: Comparison with CT. J Clin Ultrasound. 2007; 35: 256–61.
Lee JY, Kim SH, Cho JY, Han D. Color and power Doppler twinkling artifacts from urinary stones: Clinical observations and phantom studies. AJR. 2001; 176: 1441–5.
Mitterberger M, Aigner F, Pallwein L. Sonographic detection of renal and ureteral stones. Value of the value of the twinkling sign. Braz J Urol Int. 2009; 35(5): 532–41.
Turrin A, Minola P, Costa F. Diagnostic value of colour Doppler twinkling artefact in sites negative for stones on B mode renal sonography. Urol Res. 2007; 35: 313–7.
Winkel RR, Kalhauge A, Fredfeldt K. The usefulness of ultrosound colour-Doppler twinkling artifact for detecting urolithiasis compared with low dose non enhanced computerized tomography. Ultrasound in Med & Biol. 2012; 38(7): 1–8.
Osman Y, El-Tabey N, Refai H. Detection of residual stones after percutaneous nephrolithotomy: Role of non enhanced spiral computerized tomography. J Urol. 2008; 179: 198–200.
Aytac SK, Ozcan H. Effect of color Doppler system on the twinkling sign associated with urinary tract calculi. JCU. 1999; 27: 433–9.
Park SJ, Yi BH, Lee HK. Evaluation of patients with suspected ureteral calculi using sonography as an initial diagnostic tool: How can we improve diagnostic accuracy? J Ultrasound Med. 2008; 27: 1441–50.
Korkmaz M, Aras B, Sanal B. Investigating the clinical significance of twinkling artifacts in patients with urolithiasis smaller than 5mm. Jpn J Radiol. 2014; 32(8): 482–6.
Yavuz A, Ceken K, Alimoglu E. The reliability of color Doppler twinkling artifact for diagnosing millimetrical nephrolithiasis: Comparison with B-Mode US and CT scanning results. J Med Ultrasonics. 2014; 42(2): 215–22.
Shabana W, Bude RO, Rubin JM. Comparison between color Doppler twinkling artifact and acoustic shadowing for renal calculus detection: An in vitro study. Ultrasound Med Biol. 2009; 35: 339–50.
Chelfouh N, Grenier N, Higueret D. Characterization of urinary calculi: In vitro study of twinkling artifact revealed by color-ﬂow sonography. AJR Am J Roentgenol. 1998; 171: 1055–60.
Alan C, Kocoglu H, Kosar S. Role of twinkling artifact incharacterization of urinary calculi. Actas Urol Esp. 2011; 35: 396–402.
Hassani H, Raynal G, Spie R. Imaging based assessment of the mineral composition of urinary stones: An in vitro study of the combination of Hounsfield unit measurement in noncontrast helical computerized tomography and the twinkling artifact in color Doppler ultrasound. Ultrasound in Medicine and Biology. 2012; 38(5): 803–10.
Kamaya A, Tuthill T, Rubin JM. Twinkling artifact on color Doppler sonography: Dependence on machine parameter and underlying cause. AJR Am J Roentgenol. 2003; 180: 215–22.