Endourology and StoneLimitations to Ultrasound in the Detection and Measurement of Urinary Tract Calculi
Section snippets
Material and Methods
We performed a retrospective review of imaging for renal and ureteric calculi at a single institution. Enrolment was limited to the period between June 2004 and December 2008. Data were abstracted from patient records and an independent review of all imaging was conducted by a Urologist. Institutional ethics approval was obtained for this study.
Inclusion was limited to patients aged ≥18 years, with the finding of a solitary renal or ureteral calculus on both US and noncontrast CT. Both CT and
Results
Data were analyzed for 60 patients with 71 renal or ureteric calculi (Table 1). In total, 56 renal and 15 ureteric stones were included. The mean interval between CT and US examinations was 9.6 ± 9.5 days. US was conducted as the initial examination in 68.3% of cases. Indications for US were follow-up of a known stone in 34 (56.7%) and as the initial imaging modality for the investigation of acute flank pain following presentation to the emergency department in 17 (28.3%). Additionally, in 8
Comment
Unenhanced axial CT has the benefit of providing rapid diagnosis with high sensitivity and specificities and is considered the gold standard imaging modality for the diagnosis of kidney stones.1 As knowledge of stone burden forms the basis of management decisions and guides clinical decision-making, accurate measurement of urinary tract calculi is essential. Now routinely performed with slice collimations of less than 3 mm, published sensitivity and specificities approach 98%-100%.14 At this
Conclusions
Overestimation of stone size may have important implications for patient counselling and may affect the choice of intervention. Our data indicate that US overestimates renal stone size, an effect that is particularly pronounced for stones ≤5 mm. Furthermore, compared with unenhanced CT, US has poor sensitivity for detecting stones in both the ureter and kidney. For these reasons, US should be considered of limited value in the work-up of urolithiasis. Management decisions should incorporate
References (24)
- et al.
Modern approach of diagnosis and management of acute flank pain: review of all imaging modalities
Eur Urol
(2002) - et al.
Computerized tomography magnified bone windows are superior to standard soft tissue windows for accurate measurement of stone size: an in vitro and clinical study
J Urol
(2009) - et al.
Doppler artifacts and pitfalls
Radiol Clin North Am
(2006) Clinical practiceAcute renal colic from ureteral calculus
N Engl J Med
(2004)- et al.
Acute flank pain: comparison of non-contrast-enhanced CT and intravenous urography
Radiology
(1995) - et al.
Textbook of Uroradiology
- et al.
Suspected ureteral colic: primary helical CT versus selective helical CT after unenhanced radiography and sonography
AJR Am J Roentgenol
(2002) - et al.
Renal colic: comparison of spiral CT, US and IVU in the detection of ureteral calculi
Eur Radiol
(1998) - et al.
Nonenhanced helical CT and US in the emergency evaluation of patients with renal colic: prospective comparison
Radiology
(2000) - et al.
Ultrasound vs CT for the detection of ureteric stones in patients with renal colic
Br J Radiol
(2001)
Unenhanced helical computed tomography in the evaluation of acute flank pain
Eur Urol
Can conventional examinations contribute to the diagnostic power of unenhanced helical computed tomography in urolithiasis?
Urol Int
Cited by (178)
Normalized Spatial Autocorrelation in Ultrasound B-Mode Imaging for Point-Scatterer Detection
2024, Ultrasound in Medicine and Biology2022 Recommendations of the AFU Lithiasis Committee: Diagnosis
2023, Progres en UrologiePoint detection in textured ultrasound images
2023, UltrasonicsDuration of Follow-up and Timing of Discharge from Imaging Follow-up, in Adult Patients with Urolithiasis After Surgical or Medical Intervention: A Systematic Review and Meta-analysis from the European Association of Urology Guideline Panel on Urolithiasis
2023, European Urology FocusCitation Excerpt :The use of a cutoff limit to guide further treatment has the main drawback of inconsistency between several imaging methods. A CT scan seems to overestimate size by 0.8 mm compared with x-ray, while ultrasound overestimates size by 1.9 mm compared with CT [76,77]. Brain et al [78] recently summarized evidence regarding the natural history of residual fragments.
Flexible Ureterorenoscopy Versus Shockwave Lithotripsy for Kidney Stones ≤2 cm: A Randomized Controlled Trial
2022, European Urology FocusCitation Excerpt :In any case, the same imaging modalities were used at the same time in both groups, guaranteeing the validity of the results. In fact, high US sensitivity (performed by independent radiologists) and the risk of stone size overestimation [25,26] may have even negatively influenced SFR results, especially in the short term. While there is no consensus on the timing of postoperative imaging for outcome evaluation, 3 mo seem to be the time point most commonly considered in the literature.
This study was presented as a poster at the Canadian Urological Association Annual Meeting, Toronto, Ontario, 2009.