A coronal-reformatted CT image (without IV contrast) shows an obstructing right ureterovesical junction (UVJ) stone (arrow), causing hydroureteronephrosis. There is enlargement of the right kidney with perinephric stranding (arrowheads) as a result.
Facts:
- Urolithiasis incidence in the U.S. and Europe approximately 0.1% - 0.4% of population
- Male to female ratio = 3:1
- Peak age during third to fifth decade of life
- Recurrence rate about 75% during 20 years
Detection Rates by Various Imaging Methods
- Conventional radiography 50-70%
- Intravenous urography (IVU) 70-90%
- Ultrasound 50-60%
- Normal-dose CT: sensitivity 94-100%, specificity 97%
- Low-dose CT: sensitivity 95%, specificity 95%
Advantages of CT over IVU
- Shorter examination time
- Avoid cost and complications of IV contrast
- Greater sensitivity for stone detection
- Higher potential for detection of abnormalities unrelated to stone disease
- Study directly compared low-dose (<>
- Meta-analysis of 7 studies of low-dose CT in 1061 patients showing 95% sensitivity and specificity for stone diagnosis
References
1. Liu W, Esler SJ, Kenny BJ, et al. Low-dose nonenhanced helical CT of renal colic: assessment of ureteric stone detection and measurement of effective dose equivalent. Radiology 2000;215:51-54.
2. Niemann T, Kollmann T, Bongartz G. Diagnostic performance of low-dose CT for the detection of urolithiasis: a meta-analysis. AJR 2008;191:396-401.
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