Performance of computed tomographic urography for the detection of bladder tumors in patients with microscopic hematuria

Abstract

Objective

Our objective was to evaluate the sensitivity, specificity, predictive value, and accuracy of computed tomographic urography for the detection of bladder tumors in patients with microscopic hematuria.

Material and methods

Patients with microscopic hematuria initially evaluated with computed tomography and cystoscopy from January 2006 to December 2009 were evaluated. Computed tomography detecting a bladder lesion suspicious of malignancy was considered positive. Cystoscopy was classified as positive when a lesion requiring biopsy or resection was found. Performance characteristics of computed tomography were determined by comparing with cystoscopic and pathological findings.

Results

A total of 112 patients were eligible for analysis. Seven tumors were found on cystoscopy; of these, 2 were correctly diagnosed by computed tomography and 5 were missed. An additional case was considered erroneously positive. The results are a sensitivity of 29%, specificity of 99%, positive predictive value of 67%, negative predictive value of 95%, and accuracy of 95%.

Conclusions

Although computed tomography has a high specificity its sensitivity is limited. For this reason conventional cystoscopy should be considered the standard for bladder evaluation of patients with microscopic hematuria.

Resumen

Objetivo

Evaluar la sensibilidad, especificidad, valores predictivos y exactitud de la tomografía computarizada en la detección de tumores vesicales en pacientes con hematuria microscópica.

Material y métodos

Analizamos retrospectivamente los casos de hematuria microscópica evaluados con tomografía computarizada y cistoscopia de enero de 2006 a diciembre de 2009. Ambos estudios se consideraron como positivos en caso de identificarse una lesión sospechosa de neoplasia. El desempeño de la tomografía computarizada fue determinado mediante los resultados de la cistoscopia y los hallazgos histológicos.

Resultados

Ciento doce pacientes fueron analizados. En 7 de ellos se identificó un tumor vesical por cistoscopia. La tomografía computarizada solo diagnosticó correctamente 2 casos y falló en 5. Un caso más fue considerado erróneamente como positivo en la tomografía computarizada. Esto resulta en una sensibilidad del 29%, especificidad del 99%, valor predictivo positivo del 67%, valor predictivo negativo del 95% y exactitud del 95%.

Conclusiones

Aunque la tomografía computarizada tiene una especificidad alta en la evaluación de pacientes con hematuria microscópica, su sensibilidad es limitada. Por tal motivo la cistoscopia debe seguir siendo el estándar en estos casos.