US Color Doppler Kidneys and Bladder Retroperitoneal There is no evidence to support the use of dedicated US color Doppler in the evaluation of patients with acute onset flank pain and suspicion for urolithiasis and with no history of stone disease. This procedure is intended for evaluation of vasculature. US Kidneys and Bladder Retroperitoneal Using grayscale techniques, US demonstrates variable performance in the detection of renal calculi depending on the clinical scenario and associated complications. Compared with noncontrast CT, initial studies evaluating grayscale US demonstrated an overall sensitivity of 24% to 57% for stone detection with decreased sensitivity for smaller stones [33,34]. Detection of ureteral calculi is also reduced compared with CT, demonstrating sensitivity up to 61% with a specificity of 100%, although sensitivity is improved if there are associated signs of obstruction US has been found to be up to 100% sensitive and 90% specific for the diagnosis of ureteral obstruction (hydronephrosis, ureterectasis, and perinephric fluid) in patients presenting with acute flank pain [37]. However, within the first 2 hours of presentation, these findings are less sensitive because secondary signs of obstruction may not have had time to develop [38]. Furthermore, although hydronephrosis on US does not accurately predict the presence or absence of a ureteral stone on computerized tomography in up to 25% of patients [39], it has been shown that in an US-first approach, the lack of hydronephrosis on US makes the presence of a larger ureteral stone (>5 mm) less likely [40]. The addition of color Doppler and assessment of twinkling artifact has been shown to provide higher sensitivity, particularly for small renal stones, with described sensitivity reported as high as 99% for stones <5 mm in patients with lumbar pain or history of renal stones [11].
Acute Onset Flank Pain Suspicion of Stone Disease Urolithiasis . US Color Doppler Kidneys and Bladder Retroperitoneal There is no evidence to support the use of dedicated US color Doppler in the evaluation of patients with acute onset flank pain and suspicion for urolithiasis and with no history of stone disease. This procedure is intended for evaluation of vasculature. US Kidneys and Bladder Retroperitoneal Using grayscale techniques, US demonstrates variable performance in the detection of renal calculi depending on the clinical scenario and associated complications. Compared with noncontrast CT, initial studies evaluating grayscale US demonstrated an overall sensitivity of 24% to 57% for stone detection with decreased sensitivity for smaller stones [33,34]. Detection of ureteral calculi is also reduced compared with CT, demonstrating sensitivity up to 61% with a specificity of 100%, although sensitivity is improved if there are associated signs of obstruction US has been found to be up to 100% sensitive and 90% specific for the diagnosis of ureteral obstruction (hydronephrosis, ureterectasis, and perinephric fluid) in patients presenting with acute flank pain [37]. However, within the first 2 hours of presentation, these findings are less sensitive because secondary signs of obstruction may not have had time to develop [38]. Furthermore, although hydronephrosis on US does not accurately predict the presence or absence of a ureteral stone on computerized tomography in up to 25% of patients [39], it has been shown that in an US-first approach, the lack of hydronephrosis on US makes the presence of a larger ureteral stone (>5 mm) less likely [40]. The addition of color Doppler and assessment of twinkling artifact has been shown to provide higher sensitivity, particularly for small renal stones, with described sensitivity reported as high as 99% for stones <5 mm in patients with lumbar pain or history of renal stones [11].