Dynamic Changes in Bladder Morphology Over Time in Cervical Cancer Patients

Area of Science:

• Medical imaging and radiation oncology
• Urology and functional anatomy

Background:

• Continuous bladder volume (BV) surveillance is crucial for urogenital disease treatment due to dynamic changes in bladder position, size, and shape.
• Understanding bladder motion is essential for accurate treatment planning and delivery.

Purpose of the Study:

• To quantify the motion and spatial changes of the urinary bladder during different filling phases.
• To establish correlations between bladder filling rate, patient factors, and volumetric changes.

Main Methods:

• Utilized daily ultrasound and weekly cone-beam CT scans from 89 patients in a supine position.
• Measured bladder volume (BV), centroid positions, and triaxial lengths (LR, AP, SI) over time.
• Compared these parameters across various bladder filling states.

Main Results:

• Bladder volume increased linearly with time; filling rate correlated with age and water consumption.
• Greatest bladder centroid motion was longitudinal (inferiorly/posteriorly) with decreasing BV.
• Triaxial length changes varied by filling phase, with significant expansion in LR, AP, and SI directions at lower volumes (10-80 mL).

Conclusions:

• Urinary filling rate can assess temporal bladder changes.
• Spatial bladder changes (centroid position, triaxial lengths) must be evaluated considering distinct filling phases for effective clinical application.