Three-Dimensional Computerized Model Based on the Sonourethrogram: A Novel Technique to Evaluate Anterior Urethral Stricture

Optimizing anterior urethral stricture assessment: leveraging AI-assisted three-dimensional sonourethrography in clinical practice

PURPOSE

This investigation sought to validate the clinical precision and practical applicability of AI-enhanced three-dimensional sonographic imaging for the identification of anterior urethral stricture.

METHODS

The study enrolled 63 male patients with diagnosed anterior urethral strictures alongside 10 healthy volunteers to serve as controls. The imaging protocol utilized a high-frequency 3D ultrasound system combined with a linear stepper motor, which enabled precise and rapid image acquisition. For image analysis, an advanced AI-based segmentation process using a modified U-net algorithm was implemented to perform real-time, high-resolution segmentation and three-dimensional reconstruction of the urethra. A comparative analysis was performed against the surgically measured stricture lengths. Spearman's correlation analysis was executed to assess the findings.

RESULTS

The AI model completed the entire processing sequence, encompassing recognition, segmentation, and reconstruction, within approximately 5 min. The mean intraoperative length of urethral stricture was determined to be 14.4 ± 8.4 mm. Notably, the mean lengths of the urethral strictures reconstructed by manual and AI models were 13.1 ± 7.5 mm and 13.4 ± 7.2 mm, respectively. Interestingly, no statistically significant disparity in urethral stricture length between manually reconstructed and AI-reconstructed images was observed. Spearman's correlation analysis underscored a more robust association of AI-reconstructed images with intraoperative urethral stricture length than manually reconstructed 3D images (0.870 vs. 0.820). Furthermore, AI-reconstructed images provided detailed views of the corpus spongiosum fibrosis from multiple perspectives.

CONCLUSIONS

The research heralds the inception of an innovative, efficient AI-driven sonographic approach for three-dimensional visualization of urethral strictures, substantiating its viability and superiority in clinical application.

Contrast-enhanced voiding urosonography part 2: urethral imaging

Ultrasound (US) has been increasingly used as an important imaging tool to assess the urethra in children. The earliest reports of pediatric urethral sonography involved imaging the urethra in a non-voiding state, during physiological voiding of urine, and after instillation of saline. The introduction of US contrast agents has continued to improve visualization of urethral anatomy. Contrast-enhanced US of the urethra can be performed during the voiding phase of a standard contrast-enhanced voiding urosonography (ceVUS) exam or with retrograde instillation of a contrast agent, depending on the exam indication. Both techniques are well tolerated by children and provide accurate information about urethral pathology and periurethral soft tissues. This article reviews the technical aspects and imaging findings of urethral pathologies in children using contrast-enhanced US, both by the voiding and retrograde instillation techniques.

Three-dimensional measurement and analysis of benign prostatic hyperplasia

Background

The volume and thickness of intravesical prostatic protrusion and other characteristics of benign prostatic hyperplasia have not been investigated. We determine the effects of age and prostate volume on anatomical features of benign prostatic hyperplasia using three-dimensional measurement in this study.

Methods

This retrospective study included a total of 98 patients with benign prostatic hyperplasia. Three-dimensional models of prostate, central gland, peripheral zone, intravesical prostatic protrusion, prostatic urethra and bladder were reconstructed according to pelvic T2-weighted magnetic resonance imaging of these patients. The models were used to measure the intravesical prostatic protrusion volume, intravesical prostatic protrusion thickness, intravesical prostatic protrusion index, intravesical prostatic protrusion, prostate volume, peripheral zone volume, peripheral zone thickness, peripheral zone index, prostatic urethra thickness, the angle and distance of distal prostatic urethra with regard to coronal plane and sagittal plane and so on.

Results

Intravesical prostatic protrusion volume, intravesical prostatic protrusion thickness and peripheral zone volume of prostate volume >80 mL group were significantly higher than these in prostate volume <80 mL group (P<0.001, 0.01, 0.01, respectively). These parameters significantly increased with age (P<0.001, 0.01, 0.05, respectively). Peripheral zone index was significantly lower of prostate volume >80 mL group than these in prostate volume <80 mL group (P<0.05). Peripheral zone index significantly decreased with age (P<0.01). Intravesical prostatic protrusion index had no significant difference in all age groups. Peripheral zone thickness and prostatic urethra thickness had no significant difference in all groups. The distance and angle of distal prostatic urethra prostatic urethra with regard to coronal plane were significantly higher than these with regard to sagittal plane (both P<0.001).

Conclusions

The rearward slope of the prostatic urethra is greater than the left or right offset during the process of benign prostatic hyperplasia. Three-dimensional measurement provides good supports for further clinical and scientific research.

Urethral Stricture Disease: Evaluation of the Male Urethra

The diagnosis of urethral stricture disease is often made when a man with obstructive voiding symptoms undergoes flexible cystoscopy (urethroscopy). However, a more complete and definitive diagnosis is then achieved when the urethra is subsequently evaluated with a retrograde urethrogram, and in many cases, a voiding cystourethrogram (VCUG). In situations where there is stricture disease involving the meatus or fossa navicularis that prevents the passage of adult flexible cystoscope, other testing appropriate in these cases include distal urethral calibration using bougie-a-boules and possibly the advancement of a pediatric cystoscope. It is only after the exact location and length and severity of the stricture is assessed that patients can be properly advised of all options before decision-making and the implementation of a treatment plan. This section will review the evaluation of the male urethra.

Historical and Current Practices in the Management of Fossa Navicularis Strictures

PURPOSE OF REVIEW

Fossa navicularis strictures represent a surgically challenging disease process that requires detailed preoperative planning and an understanding of each patient's goals in order to achieve a satisfactory long-term outcome. This review summarizes the various approaches used in the management of fossa navicularis strictures over the past several decades.

RECENT FINDINGS

In addition to existing evidence to support open flap- and graft-based reconstruction, recent studies suggest a potential role for limited open repair via a transurethral approach. Open repair of fossa navicularis strictures has become the standard of care with high success rates using local skin flaps or tissue grafts. There remains a very limited role for minimally invasive techniques in definitive management of this disease.