br Prior to the endoscopic procedure all patients underwent
Prior to the endoscopic procedure, all patients underwent high-resolution mUS assessment in a lithotomic position. Micro-US imaging was performed using the ExactVu system with an EV29L 29-MHz side-fire transducer (Exact Imaging, Markham, Canada). Two urologists (G.L.
The procedure was feasible in all female patients. We failed to evaluate two male patients because the prostate longitudinal diameter was longer than 5 cm and the bladder window was limited.
After instillation of 50 cc of saline solution, the bladder appeared triangular in shape and its content anechoic. With mUS imaging, the bladder wall appears as a three-layered structure: the urothelium appearing hyperechoic, the detrusor muscle presenting as a normoechogenic homoge-neous layer, and the adventitia appearing as a thin
Please cite this article in press as: Saita A, et al. Assessing the Feasibility and Accuracy of High-resolution Microultrasound Imaging for Bladder Cancer Detection and Staging. Eur Urol (2019), https://doi.org/10.1016/j.eururo.2019.03.044
Table 1 – Descriptive characteristics of patients with primary bladder cancer evaluated with mUS
MIBC = muscle-invasive bladder cancer; mUS = microultrasound;
NMIBC = non-muscle-invasive bladder cancer; SD = standard deviation.
hyperechoic layer (Fig. 1). The ureteric orifices appear as small, focal, round thickenings close to the bladder base.
All cancers 5 mm in size were clearly visualized, appearing as heterogeneous structures protruding from the normal
bladder wall. In NMIBC cases, lesions were not disrupting, or only focally disrupting, the hyperechoic line representing the urothelium (Fig. 2). In MIBC, tumors were clearly extending beyond this line into the muscular layer, showing a hyperechoic aspect (with or without a “starry sky” appearance) at the Acarbose of the lesion with the loss of the typical three-layer structure (Fig. 3). The endoscopic check showed a limit of resolution for the detection of bladder tumors 4 mm. No differentiation was performed between Ta and T1 tumors.
3.4. Step 4: pathological correlation
Tissue samples were obtained by standard or en bloc TUR depending on the number, size, and location of the lesions. The stage (NMIBC vs MIBC), grade, and margins (only for en bloc resection) were described. The pathologists confirmed all the 14 NMIBC patients; instead, two of the seven MIBC cases were downstaged to NMIBC at histopathological evaluation.
Our findings showed that bladder imaging with mUS is feasible and capable of describing normal bladder wall layers and BCs accurately. The concordance between mUS and histopathological results seems to confirm that mUS could be used as a noninvasive and potentially cost-effective staging device, although further data are warranted. Thus,
Table 2 – Case-by-case characteristics of the 23 patients enrolled in the study
Gender Age Smoking Urine Macrohematuria mUS Site No. Size pTNM En-bloc vs Description
(yr) status cytology
traditional of the
1 F 59 Former Negative No NMIBC Trigone 2 6–5 pTa LG En bloc Papillary 2 M 71 Yes Negative No NMIBC Left side wall 1 15 pTa LG En bloc Sessile 3 F 76 No Negative No MIBC Right side wall 1 15 pT1 HG Traditional Papillary 4 F 69 Yes Negative No NMIBC Right side wall 1 30 pTa HG Traditional Papillary 5 M 38 Yes Negative Yes NMIBC Right side wall 1 20 pTa LG En bloc Papillary 6 M 73 Yes NA Yes NMIBC Trigone, posterior wall 2 10–20 pTa LG Traditional Sessile 7 M 50 Yes Negative Yes NA Anterior wall 1 9 pTa LG Traditional Sessile 8 F 42 No Negative No NMIBC Trigone 1 20 pTa LG Traditional Papillary 9 M 79 No Negative Yes MIBC Right side wall 2 20–30 pT1 HG Traditional Flat 10 F 81 No Negative No NMIBC Multifocal 4 10–10–5–5 pTa LG Traditional Papillary 11 M 72 Former NA Yes MIBC Right side wall, trigone 1 55 pT2 HG Traditional Papillary
12 F 42 No Negative No NMIBC Left side wall 1 10 pTa LG En bloc Papillary 13 M 65 Former Positive No MIBC Trigone 1 40 pT2 HG Traditional Papillary 14 F 61 No Negative No NMIBC Left side wall 1 15 pTa LG En bloc Papillary 15 M 76 No Negative No NA Dome, anterior wall 2 15–5 pTa LG Traditional Sessile 16 M 63 Former NA Yes MIBC Left side wall, trigone 1 70 pT2 HG Traditional Sessile 17 F 76 No Negative Yes NMIBC Right side wall 1 9 pTa LG En bloc Papillary 18 F 62 Yes Negative No NMIBC Trigone 1 5 pTa HG Traditional Sessile 19 M 57 Yes Positive Yes MIBC Posterior wall, trigone 2 10–20 pT2 HG Traditional Papillary 20 F 85 No Uncertain Yes NMIBC