A Reliable and Robust Method of Measuring Male Pelvic Floor Muscle Volume Using Three-dimensional Computed Tomography

Objectives: The pelvic floor muscle (PFM) plays a major role in sexual and urinary functions. No objective method exists to measure the PFM in male. This study evaluated the reliability of male PFM volume using three-dimensional computed tomography (3D-CT).

Methods: PFMs of five patients aged 43-83 years were selectively extracted from thin-slice CT using a workstation to reconstruct stereoscopic images and measure PFM volume. Two raters measured the PFM volume three times in all patients to confirm the reliability of PFM volume measurement. Intra- and inter-rater correlation coefficients, i.e., intraclass correlation coefficient, were determined. The CT attenuation of PFMs was also evaluated.

Results: Raters 1 and 2 reported an average PFM volume of 46.4 ± 11.5 cm³ and 46.1 ± 12.5 cm³, respectively. The intra- and inter-rater correlation coefficients were 0.99 and 0.98, respectively. The average CT value of PFMs had a minimum of 13.7 Hounsfield Unit (HU) in the eldest male and a maximum of 38.9 HU in the youngest male.

Conclusions: Male PFMs could be selectively extracted using a workstation to reconstruct a stereoscopic image. The PFM volume measurement is feasible and highly reproducible. To our knowledge, this is the first study that standardizes the method for measuring the male PFM volume using 3D-CT and examines its reliability.