ABSTRACT

The aim of study was to evaluate the inter-observer reliability in assessing anterior and posterior pelvic floor compartments in nulliparous women using 3-dimensional endovaginal ultrasound, and to evaluate the association of age with the visualization or measurement of these structures. 3D EVUS images were obtained in community-dwelling nulliparous women ages 21-80. Two observers independently read all images, looking anteriorly for the vesical trigone (VT), trigonal ring (TR), trigonal plate (TP), striated urogenital sphincter (SUG), compressor urethra (CU), longitudinal and circular smooth muscle (LCM); posterior structures included the superficial external anal sphincter (EAS-sq), main external anal sphincter (EAS-m), internal anal sphincter (IAS), and rectovaginal septum (RVS). Urethral, RVS, and anal sphincter measurements were recorded. Inter-observer reliability was determined with Cohen’s kappa. Spearman’s rank correlation was used to evaluate the association between these measurements and age. Ultrasound images of 77 volunteers, including anterior and posterior compartment 3D volumes (total of 154), were analyzed for this study. The median measurements were: urethral length 3.68 cm (range 1.67, 6.84), IAS length 2.60 cm (range 1.74, 4.12), IAS width 0.32 cm (range 0.17, 0.63), RVS length 3.02 cm (range 2.15, 3.98), anorectal angle 157° (range 142, 168). Inter-observer agreement for the visualization of structures was substantial to almost perfect. There was no correlation between age and variations in urethral length, IAS length or width, RVS length or anorectal angle. 3D EVUS can reliably identify anterior and posterior compartment structures. Age is not associated with the visualization or measurement of these structures.