The role of bladder imaging with Shear Wave Elastography in the diagnosis of overactive bladder in women

Objective:To identify biomechanical changes in the bladder wall using ultrasonographic shear wave elastography in the evaluation of female patients with overactive bladder (OAB) symptoms. Materials and Methods: Between January 2024 and January 2025, 22 female patients aged 20–60 years (Group 1) who presented with OAB symptoms to the Urology Outpatient Clinic of Tokat Gaziosmanpaşa University Faculty of Medicine Hospital and had not received any prior treatment were included in the study. Additionally, 25 individuals without any urological symptoms were enrolled as the control group (Group 2). Ultrasonographic parameters, age distribution, International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) scores, Validated Overactive Bladder Questionnaire-V8 (OAB-V8) scores, bladder diaries, post-void residual urine volumes, uroflowmetry measurements, and complete urinalysis results were recorded after a general urological examination. The correlation between biomechanical parameters measured using sonoelastographic techniques and clinical diagnosis was analyzed. Bladder wall sonoelastographic evaluations were performed using a Logiq E9 device (GE Healthcare, Milwaukee, USA) with a 9L MHz probe. Measurements were documented, and values were compared between the patient and control groups. Results: The mean age of Group 1 was 41.86±12.19 years, while that of Group 2 was 32.44±6.58 years (p=0.003). The groups were further analyzed based on body mass index (BMI), parity and smoking status. In Group 1, the BMI was 27.20±5.65 kg/m², parity was 1.86±1.64, and 2 patients were smokers. In Group 2, the BMI was 24.52±4.17 kg/m², parity was 0.64±0.95, and 8 patients were smokers. No statistically significant difference was found between the groups regarding BMI (p=0.068), but parity differed significantly (p=0.003). The mean symptom duration in Group 1 was 30.82±23.86 months. The nocturia value was 2.04±1.09 in Group 1 and 0.4±0.86 in Group 2 (p<0.001). At presentation,%45.5 (n=10) of the patients had urgency urinary incontinence (wet-type OAB), while %54.5 (n=12) had no incontinence and were classified as having dry-type OAB. The mean daily voiding frequency in Group 1 was 9.95±2.06. OAB-V8 and ICIQ-SF scores significantly differed between the two groups (p<0.001). Uroflowmetric parameters in Group 1 were as follows: mean Qmax, Qave, and voided volume were 28.06±12.81 mL/s, 14.12±5.45 mL/s, and 286.65±212.60 mL, respectively. No significant difference was observed in post-void residual (PVR) urine volumes between the groups (35.00±17.75 mL vs. 28.40±17.84 mL, p>0.05). Regarding shear wave elastography values, Group 1 had a mean velocity of 1.11±0.18 m/s and stiffness of 3.98±0.99 kPa, while Group 2 had a velocity of 1.13±0.19 m/s and stiffness of 4.20±1.35 kPa. No statistically significant difference was found between the groups in terms of velocity (p=0.71) or stiffness (p=0.531). A strong negative correlation was identified between anterior stiffness and Qmax (p<0.001) and between anterior velocity and Qmax (p=0.016). A significant positive correlation was found between left lateral velocity and Qmax (p=0.045) as well as between left lateral stiffness and both Qave (p=0.026) and Qmax (p=0.018). Additionally, a negative correlation was observed between posterior velocity and Qmax (p=0.017). Bladder wall thickness measured from the anterior wall was 2.57 mm in Group 1 and 2.74 mm in Group 2 (p=0.435). Conclusion: Shear wave elastography is a method used to assess tissue elasticity in various organ pathologies and has potential applications in evaluating bladder dysfunctions. In our study, negative correlations were identified between anterior stiffness and velocity as well as posterior velocity and Qmax, while significant positive correlations were observed between left lateral velocity and Qmax and between left lateral stiffness and both Qave and Qmax. These findings suggest that ultrasonographic shear wave elastography may serve as an important diagnostic tool for detecting biomechanical changes in the bladder wall and predicting their relationship with disease severity. This technique may reduce the necessity for invasive tests such as urodynamics in the diagnosis and treatment planning of OAB. Furthermore, it has the potential to contribute to the development of treatment strategies and monitoring of existing therapeutic processes in OAB. However, further randomized controlled clinical trials with larger patient populations are needed to evaluate the clinical applicability of ultrasonographic shear wave elastography in patients with OAB. Keywords: overactive bladder, ultrasonography, elastography, diagnosis