Radiographic calibration for pubic diastasis assessment in bladder exstrophy-epispadias complex: a phantom study

Area of Science:

• Pediatric Radiology
• Surgical Planning
• Medical Imaging Analysis

Background:

• Accurate assessment of pubic diastasis is vital for surgical planning in bladder exstrophy-epispadias complex.
• Radiographic measurements of pubic diastasis can be influenced by patient size, imaging protocols, and equipment.
• Standardization methods like image calibration and anatomic ratios may improve measurement reliability.

Purpose of the Study:

• To evaluate the impact of radiographic calibration on pubic diastasis measurements using imaging phantoms.
• To assess the effectiveness of an internal anatomic ratio in accounting for growth-related changes.
• To determine if calibration mitigates variations caused by different imaging techniques and equipment.

Main Methods:

• Computed tomography (CT) phantoms of varying sizes (infant, child, older child) were imaged using multiple pelvic radiography techniques.
• Simulated pubic diastasis and sacral width were measured with and without image calibration.
• Measurements were repeated across three different imaging system manufacturers.

Main Results:

• Excellent interrater agreement (ICC > 0.99) was achieved for all measurements.
• Image calibration significantly improved the accuracy of anterior pubic diastasis measurements (p=0.04) by reducing magnification effects.
• Calibration resolved significant differences in simulated pubic distance measurements between different imaging techniques (p=0.04), restoring consistency (p=0.6).

Conclusions:

• Image calibration provides more uniform and accurate pubic diastasis measurements, essential for consistent clinical application.
• Calibration is necessary for reliable inter-pubic distance measurements across diverse patient sizes, imaging techniques, and equipment.
• While small differences in pelvic ratios may not be clinically significant, calibration is recommended for optimal accuracy.