Four-dimensional reconstruction and characterization of bladder deformations.

Area of Science:

• Medical Imaging
• Biomechanical Engineering
• Urology

Background:

• Pelvic floor disorders are common, yet poorly understood, hindering effective patient care.
• Current clinical observations of pelvic floor dynamics are limited to 2D and do not fully capture 3D mechanical defects.
• Understanding bladder deformation is crucial for diagnosing and treating pelvic floor disorders.

Purpose of the Study:

• To develop a methodology for 3D representation of bladder deformations during straining exercises.
• To combine 3D bladder deformation with 3D surface strain analysis.
• To provide a tool for better understanding pelvic organ prolapse pathophysiology.

Main Methods:

• Utilized novel image segmentation and registration techniques with multi-slice MRI.
• Reconstructed real-time dynamic bladder volumes using three geometrical configurations.
• Applied in-bore forced breathing exercises to simulate straining conditions.

Main Results:

• Achieved real-time 3D deformation fields of the bladder during strain for the first time.
• Demonstrated average bladder volume deviations of approximately 2.5% in control subjects.
• Attained high registration accuracy with mean distance of 0.4 ± 0.3 mm and Hausdorff distance of 2.2 ± 1.1 mm.

Conclusions:

• The developed framework enables accurate 3D+t spatial tracking of bladder deformations.
• This method has direct clinical applications for understanding pelvic organ prolapse.
• Potential for characterizing pelvic floor pathologies and aiding preoperative surgical planning.