A prospective evaluation of conventional cystography for detection of urine leakage at the vesicourethral anastomosis site after radical prostatectomy based on computed tomography

Abstract

Aim: To evaluate the diagnostic accuracy of conventional cystography for the detection of urine leakage at the vesicourethral anastomosis (VUA) site after radical prostatectomy based on computed tomography (CT) cystography.

Materials and methods: Patients who underwent radical prostatectomies at a single tertiary cancer centre were prospectively enrolled. Conventional cystography was routinely performed on postoperative day 7. Non-enhanced pelvic CT images were obtained after retrograde instillation of the same contrast material for a reference standard of urine leakage at the VUA site. Urine leakage was classified as follows: none; a plication abnormality; mild; moderate; and excessive.

Results: One hundred and twenty consecutive patients were enrolled. Conventional cystography detected 14 urine leakages, but CT cystography detected 40 urine leakages, which consisted of 28 mild and 12 moderate urine leakages. When using CT cystography as the standard measurement, conventional cystography showed a diagnostic accuracy of 17.8% (5/28) for mild urine leakage and 75% (9/12) for moderate leakage. Of nine patients diagnosed with mild leakage on conventional cystography, four (44.4%) had complicated moderate urine leakages based on CT cystography, requiring prolonged catheterization. The sensitivity, specificity, positive and negative predictive values, and accuracy of conventional cystography were 35, 100, 100, 75.4, and 78.3%, respectively.

Conclusions: Conventional cystography is less accurate than CT cystography for diagnosing urine leakage at the VUA site after a radical prostatectomy. The present results suggest that CT cystography is a good choice for diagnostic imaging of urine leakage after radical prostatectomy.