Bladder tumor staging: comparison of contrast-enhanced and gray-scale ultrasound.
OBJECTIVE
The purpose of this study was to evaluate the effectiveness of contrast-enhanced sonography in comparison with conventional sonography in differentiating muscle-infiltrating and superficial neoplasms of the urinary bladder.


METHODS
Conventional and contrast-enhanced sonography were performed on 34 consecutively registered patients with bladder tumors. All examinations were reviewed by two independent sonologists. At gray-scale sonography, interruption of the hyperechoic bladder wall was considered the main diagnostic criterion for differentiating superficial and infiltrating tumors. At contrast-enhanced sonography, a tumor was considered superficial when the hypoenhancing muscle layer of the bladder wall was intact; disruption of the muscle layer by enhancing tumor tissue was considered diagnostic of infiltration. A level of confidence in the diagnosis of tumor infiltration of the muscle layer was assigned on a 5-degree scale. Receiver operating characteristic analysis was used to assess overall confidence in the diagnosis of muscle infiltration by tumor at both conventional and contrast-enhanced sonography. Histologic diagnosis was obtained for all patients.


RESULTS
Final pathologic staging revealed 25 superficial tumors (Ta-T1 disease) and nine muscle-infiltrating tumors (>T1). Conventional sonography depicted five of nine muscle-infiltrating tumors, and contrast-enhanced sonography depicted all nine. The diagnostic performance of contrast-enhanced sonography approached that of the reference standard (area under the receiver operating characteristic curve, 0.996), but the diagnostic performance of gray-scale ultrasound was worse (area under curve, 0.613).


CONCLUSIONS
Our study showed that contrast-enhanced sonography is better than conventional sonography for differentiating muscle-infiltrating and superficial neoplasms of the urinary bladder.
Caruso
Giuseppe
G
Dipartimento di Biotecnologie mediche e Medicina legale, Sezione di scienze radiologiche, Università degli Studi di Palermo, Via del Vespro 127, Palermo 90127, Italy. carusogi@libero.it
Salvaggio
Giuseppe
G
Campisi
Antonella
A
Melloni
Darwin
D
Midiri
Massimo
M
Bertolotto
Michele
M
Lagalla
Roberto
R
D000368:Aged; D003287:Contrast Media; D003558:Cystoscopy; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012372:ROC Curve; D014463:Ultrasonography; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
D003287:Contrast Media