Korean J Urol.  2008 Dec;49(12):1094-1099.

Predicting Factors for Spontaneous Passage of Ureteral Calculi Based on Unenhanced Helical CT Findings

• Song DW
• Jeong TY
• Lee SI
• Kim DJ

Abstract

PURPOSE: We performed a prospective study to determine whether unenhanced helical computed tomography(UHCT) findings predict the spontaneous passage of ureteral calculi.
MATERIALS AND METHODS
Between April 2006 and June 2007, 175 patients with a single ureteral calculus <1cm in diameter were enrolled in this study, and a UHCT was performed. All of the patients were managed conservatively for 2 weeks. Patients without spontaneous passage of ureteral calculi within 2 weeks were treated by ureteroscopy or extracorporeal shock wave lithotripsy(ESWL). The secondary signs (hydronephrosis, perinephric edema, and the tissue rim sign) were graded on a scale of 0-3. We evaluated whether spontaneous passage of ureteral calculi was associated with stone diameter, location, Hounsfield units(HU), and the degree of secondary signs.
RESULTS
Ninety-two patients(52.6%) had spontaneous passage of ureteral calculi. The mean stone diameter was significantly smaller in the passage group than the non-passage group(4.28mm vs. 6.73mm, p=0.002). The rate of spontaneous passage was significantly higher involving distal ureteral calculi(66.1%) than proximal ureteral calculi(30.3%, p<0.001). The incidences of hydronephrosis and perinephric edema were significantly lower in the spontaneous passage group than the non-passage group(8.7% vs. 73.5% and 5.4% vs. 69.9%, respectively). The grades of hydronephrosis and perinephric edema were significantly lower in the spontaneous passage group than the non-passage group(p=0.001). Although there was a tendency toward increasing grades of hydronephrosis and perinephric edema with increasing stone size, the grades were more frequent and severe in the non-passage group in patients with similarly sized stones.
CONCLUSIONS
The degree of hydronephrosis and perinephric edema are useful ancillary signs in predicting the likelihood of spontaneous passage of ureteral calculi.

Keyword

Ureteral calculi; Helical computed tomography

MeSH Terms

Edema
Humans
Hydronephrosis
Incidence
Prospective Studies
Shock
Tomography, Spiral Computed
Ureter
Ureteral Calculi
Ureteroscopy

Figure

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  Fig. 1. Unenhanced helical CT revealed hydronephrosis, renal enlargement, and perinephric edema (white arrow) in a patient with acute right-sided flank pain.

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  Fig. 2. Axial unenhanced helical CT images showed ureteral stones and a tissue rim sign (white arrow).

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  Fig. 3. Incidence of secondary signs related to stone diameter.

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  Fig. 4. Mean grade of secondary signs related to stone diameter.

Reference

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