Urologists will benefit from an imaging modality which can assess intra- and extra-luminal characteristics of urethral strictures. We conducted a prospective pilot study evaluating the utility of contrast-enhanced ultrasound and shear wave elastography for the evaluation of bulbar urethral stricture disease.
Patients with a single, bulbar urethral stricture were prospectively recruited. Contrast-enhanced ultrasound and shear wave elastography were performed at the time of surgical repair and at 4 months follow up using an Aplio i800 scanner (Canon Medical Systems, Tustin, CA) with an i8CX1 transducer. Sulfur hexafluoride lipid-type A microsphere ultrasound contrast (Lumason®, Bracco Imaging, Princeton, NJ) was injected retrograde through the urethra. Stiffness of the corpus spongiosum was measured at and adjacent to the stricture site. Stricture lengths based on retrograde urethrogram, grayscale ultrasound, and contrast-enhanced ultrasound were correlated with measured intraoperative stricture length.
Thirty men were enrolled. Contrast-enhanced ultrasound (R2=0.709) showed the best correlation with measured intraoperative measured stricture length compared to retrograde urethrogram (R2=0.016) or grayscale ultrasound (R2=0.471). Stiffness of the spongiosum was greater at the site of the stricture (32.6±5.4 versus 27.3±5.8 kPa, p=0.044) and in narrower caliber strictures (p=0.044) but did not differ by stricture length (p=0.182). At follow up (4.3±1.1 months) contrast-enhanced ultrasound detected stricture recurrence with 80% sensitivity, 100% specificity, and 93% accuracy compared to cystoscopy.
This pilot study demonstrated the ability of contrast-enhanced ultrasound and shear wave elastography to become safe, accurate, and potentially efficacious modalities for assessing bulbar urethral strictures and spongiofibrosis.
The Journal of urology. 2021 Aug 24 [Epub ahead of print]
Paul H Chung, Joon Yau Leong, Priscilla Machado, Corinne E Wessner, Edouard J Trabulsi, Ethan J Halpern, John R Eisenbrey, Flemming Forsberg
Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania., Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania.