Elastographic Analysis of Urothelial Bladder Tumours

Overview

The preoperative evaluation of bladder tumors includes either computed tomography, magnetic resonance imaging in B-mode, or a cystoscopy in the absence of a radiological diagnosis. The diagnosis is confirmed after a transurethral resection of the bladder (TURB) and a histopathological analysis. Ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to produce images of internal structures. Conventional ultrasound in B-mode can only provide details about the tumor's number, size, and location. Elastography uses ultrasound imaging techniques to examine the stiffness of a tissue. Using the Aixplorer system many recently published papers suggested that ShearWave Elasticity (SWE) imaging, enables the differentiation of low- from high-grade breast tumors by assessing the elasticity of the tissue. Investigators intend to evaluate the stiffness of bladder tumors with ultrasound elastography in comparison with cystometry parameters and tumoral grade.

According to European and French guidelines, Transurethral resection of the bladder can be followed by an administration of early postoperative intravesical chemotherapy. This treatment is indicated in the absence of presumed high grade tumor (preoperative high grade cytology) and in the absence of post-operative haematuria and bladder perforation. Unfortunately, urine cytology has a sensitivity for the detection of high-grade tumour of only 50%. Therefore, it is essential to predict more precisely the bladder tumor grade. Ultrasound is a non-invasive imaging technique that uses high-frequency sound waves to produce images of internal structures. Conventional ultrasound in B-mode can only provide details about the tumor's number, size, and location. Elastography uses ultrasound imaging techniques to examine the stiffness of a tissue. Using the Aixplorer system many recently published papers suggested that ShearWave Elasticity (SWE) imaging, enables the differentiation of low- from high-grade breast tumors by assessing the elasticity of the tissue. Many studies have shown a significant correlation between ultrasound elastography of the bladder wall with measurements of the detrusor pressure. Only one study, conducted by Huang et al., have assessed its application in the evaluation of bladder cancer with an intraluminal transducer. A significant difference between elasticity of low grade and high grade bladder tumors was found. However, no data on the impact of the intravesical volume over the tumoral elasticity is available. The objective of this project is to evaluate the correlation between the ultrasound Elastography of urothelial bladder tumors with their tumoral grade before transurethral resection of the bladder. Knowing that ultrasound Elastography is impacted by the pressure applied to a tissue, investigators intend to measure the tumoral elasticity - with an abdominal ultrasound transducer - during bladder filling with a monitoring of the intravesical pressure.