Comparative study of novel endoluminal ultrasonography and conventional transurethral ultrasonography in staging of bladder cancer

Abstract

Background: Recent advances in ultrasonic techniques have improved the image quality and diagnostic accuracy for staging of bladder cancer. The aim of this study was to assess the feasibility and usefulness of endoluminal ultrasonography (ELUS) in staging of bladder cancer, and to compare them with those of conventional transurethral ultrasonography (TUUS). Methods: From 2000 to 2002, 19 patients with bladder cancer were evaluated by ELUS and TUUS before transurethral resection or biopsy. Clinical staging using ELUS, TUUS, computed tomography (CT) and magnetic resonance imaging (MRI) was compared with the results of pathological staging. Results: In 16 of 19 patients, both ELUS and TUUS were able to diagnose tumor stage. In the remaining three patients, both methods were unable to evaluate stage of tumor. In two of these patients, this inability to evaluate tumor state was caused by a difficulty in depicting the tumor base in rectangular scanning. In the remaining patient, the inability to evaluate tumor stage was caused by a difficulty in recognizing the normal muscularis because of edema around the tumor base. Both diagnostic accuracies of ELUS and TUUS were 84%, which were superior to those of CT (44%) and MRI (82%). Conclusions: Endoluminal ultrasonography and TUUS were equally useful for staging diagnosis of bladder cancer. Because the ELUS probe is very small in diameter and can be manipulated under direct vision, it is superior to the TUUS in safety and in fine visualization. However, the main limitations of ELUS include an inability to evaluate the depth of invasion of large tumors and an inability to visualize the tumor base in the position of the bladder neck.