Accuracy of residual urine measurement in men: comparison between real-time ultrasonography and catheterization

Area of Science:

• Urology
• Medical Imaging

Background:

• Accurate measurement of post-void residual (PVR) urine volume is crucial for managing lower urinary tract symptoms.
• Traditional methods like catheterization are invasive, while non-invasive techniques require validation.

Purpose of the Study:

• To evaluate the practical value and accuracy of ultrasonography for determining residual urine volume in men.
• To assess the correlation between ultrasound-derived bladder volume calculations and actual measured residual urine.

Main Methods:

• Real-time ultrasonography was used to measure bladder dimensions (diameters and areas) in 324 men post-voiding.
• Eleven established formulas were applied to calculate bladder volumes from ultrasonographic measurements.
• Calculated volumes were compared against measured total residual urine volumes.

Main Results:

• Ultrasonography had a lower limit of urine visualization around 48 ml.
• No significant correlation was found between calculated bladder volumes using any of the 11 formulas and measured residual urine.
• Ultrasonographic methods failed to accurately determine residual urine volume in this cohort.

Conclusions:

• Current ultrasonographic techniques are not yet reliable for rapid and accurate measurement of post-void residual urine volume.
• Catheterization, despite its invasiveness, remains the most accurate method for PVR assessment.
• Alternative, less invasive methods for PVR assessment require further development and validation.