CONTRAST-ENHANCED ULTRASOUND (CEUS) IN DETECTION OF SESSILE BLADDER CARCINOMAS: PRELIMINARY DATA
According to scientific literature and EAU guidelines the most accurate diagnostic exam for detection and follow up of vescical lesion is cystoscopy. In daily practice, ultrasonography is often adopted as a non invasive examination which is proposed to avoid iterate invasive procedures. The most important limitation of ultrasonography large application is the low detection rate of small and sessile tumors and the inability to identify the aggressiveness of bladder tumors. The aim of the study is to evaluate the efficacy of contrast – enhanced ultrasound (CEUS) in detecting sessile bladder carcinomas to tailor a preoperative planning and timing and high-sensitive, non invasive postoperative follow-up
Methods and results
We prospectively evaluated with CEUS 82 patients with cystoscopically-detected bladder tumors. Lesions were first scanned with a gray-scale ultrasonography and color Doppler US to obtain their location and size and the best imaging plane to observe the lesions and the normal adjacent bladder wall. Thereafter, contrast enhanced agent (SonoVue, Bracco®, Milan, Italy) was injected intravenously as a bolus (average 2.5 ml/sec ) 4.8 ml dose followed by 10 ml of normal saline flush. Each exam lasted about 3 min following bolus injection. One post-contrast cine clip was acquired lasting approximately 150 sec. If necessary, the injection was repeated 15 min later. A quantitative analysis of enhancement was performed using a dedicated software (QONTRAST, manufactured by Esaote for Bracco Group) which elaborates colorimetric maps and process Time/Intensity (T/IS) curves on region of interest (ROI). All patients underwent transurethral resection (TURBT) according to EAU Guidelines recommendations. In case of multifocal tumors, every lesion was sent separately to histopatologic evaluation.
During preliminary cystoscopic evalution there were found 39 sessile and 95 papillary tumors. Overall, conventional gray-scale ultrasonography (US) and CEUS identified 110 of the 134 bladder lesions discovered during cystoscopy. At preliminary gray-scale US were identified 17/39 (43.6%) sessile lesions and 61/95 (64.2%) of papillary lesions; mean (range) dimensions were 9 (5-22)mm and 12 (4-36)mm respectively. Overall, after contrast injection there were discovered 30/39 (76.9%) sessile and 80/95 (84.2%) papillary lesions. All lesions undiscovered during gray-scale US were found to be very slightly exophytic (mean 2mm, range 1-6mm). At histopathological evaluation all tumors resulted transitional cell bladder carcinomas; of these, sessile lesions were identified as Ta low-grade (LG) in 3/39 cases (7.7%), Ta high-grade (HG) in 7/39 (17.9%), T1 HG in 28/39 (71.8%) 1 T2 (2.6%). Overall, 31/95 (32.7%) papillary lesions were found to be Ta low-grade (LG), 7/95 (7.3%) Ta high-grade (HG), 52/95 (54.8%) were T1 HG and 5/95 (5.2%) T2. CEUS resulted statistically significant (p<0.0001) in detection of both, sessile and papillary tumors and determinant in increasing the detection rate compared to standard grey-scale US: 43.6 Vs 76.9 for sessile tumors and 64.2 Vs 84.2 for papillary ones respectively. None of the patients has suffered adverse reactions to CEUS contrast agent, and no renal function worsening was suspected.
In our experience contrast enhanced ultrasound demonstrated to be a safe, fast and low cost procedure. It doesn't require a long learning curve and the hard disk storage of every exam allows to perform time/intensity curves in post processing phase.
Contrast-enhanced ultrasound can be useful to better define bladder carcinomas: in our experience CEUS demonstrated an high detection rate both for papillary and sessile tumors. Wider series may conduce to a more accurate predictivity of T/IS curves and to develop a tailored preoperative planning and timing; moreover CEUS may be useful in postoperative follow-up of patients with sessile Ta-T1 tumors non suitable to the recommended repeated cystoscopic schedule.