Inter-observer variability in male pelvic-floor MRI measurements that might predict post-prostatectomy incontinence

Area of Science:

• Radiology and Urology
• Medical Imaging Analysis
• Pelvic Floor Anatomy

Background:

• Preoperative prostate MRI anatomical variables are increasingly studied for predicting post-prostatectomy incontinence (PPI).
• Limited evidence exists on the reliability of these anatomical measurements.
• Assessing inter-observer agreement is crucial for validating these predictors.

Purpose of the Study:

• To evaluate the concordance between urologists and radiologists in measuring anatomical variables on preoperative prostate MRI.
• To determine the reliability of these measurements as potential predictors of post-prostatectomy incontinence (PPI).

Main Methods:

• Two radiologists and two urologists independently performed pelvic floor measurements using 3T-MRI.
• Measurements were conducted blindly to ensure objectivity.
• Interobserver agreement was quantified using the intraclass correlation coefficient (ICC) and Bland-Altman plots.

Main Results:

• Good-acceptable agreement was observed for most measurements, including intravesical prostatic protrusion (IPP) and prostate volume (ICC > 0.60).
• Membranous urethral length (MUL) and the angle of the membranous urethra-prostate axis (aLUMP) showed moderate agreement (ICC > 0.40).
• Levator ani and puborectalis muscle thickness exhibited poor agreement (ICC < 0.20), indicating low reliability.

Conclusions:

• Measurements like MUL, IPP, prostate volume, aLUMP, obturator internus muscle thickness (OIT), urethral width, and prostatic length demonstrate acceptable inter-observer concordance.
• These parameters are considered reliable predictors for post-prostatectomy incontinence (PPI).
• Levator ani and puborectalis muscle thickness measurements are unreliable due to poor agreement.