Agreement and reliability of pelvic floor measurements during rest and on maximum Valsalva maneuver using three-dimensional translabial ultrasound and virtual reality imaging.
OBJECTIVE
Imaging of the levator ani hiatus provides valuable information for the diagnosis and follow-up of patients with pelvic organ prolapse (POP). This study compared measurements of levator ani hiatal volume during rest and on maximum Valsalva, obtained using conventional three-dimensional (3D) translabial ultrasound and virtual reality imaging. Our objectives were to establish their agreement and reliability, and their relationship with prolapse symptoms and POP quantification (POP-Q) stage.


METHODS
One hundred women with an intact levator ani were selected from our tertiary clinic database. Information on clinical symptoms were obtained using standardized questionnaires. Ultrasound datasets were analyzed using a rendered volume with a slice thickness of 1.5 cm, at the level of minimal hiatal dimensions, during rest and on maximum Valsalva. The levator area (in cm(2) ) was measured and multiplied by 1.5 to obtain the levator ani hiatal volume (in cm(3) ) on conventional 3D ultrasound. Levator ani hiatal volume (in cm(3) ) was measured semi-automatically by virtual reality imaging using a segmentation algorithm. Twenty patients were chosen randomly to analyze intra- and interobserver agreement.


RESULTS
The mean difference between levator hiatal volume measurements on 3D ultrasound and by virtual reality was 1.52 cm(3) (95% CI, 1.00-2.04 cm(3) ) at rest and 1.16 cm(3) (95% CI, 0.56-1.76 cm(3) ) during maximum Valsalva (P < 0.001). Both intra- and interobserver intraclass correlation coefficients were ≥ 0.96 for conventional 3D ultrasound and > 0.99 for virtual reality. Patients with prolapse symptoms or POP-Q Stage ≥ 2 had significantly larger hiatal measurements than those without symptoms or POP-Q Stage < 2.


CONCLUSIONS
Levator ani hiatal volume at rest and on maximum Valsalva is significantly smaller when using virtual reality compared with conventional 3D ultrasound; however, this difference does not seem clinically important. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Department of Obstetrics and Gynecology, Division of Urogynecology, Erasmus Medical Center, Rotterdam, The Netherlands.
L
L
Speksnijder
Department of Obstetrics and Gynecology, Division of Urogynecology, Erasmus Medical Center, Rotterdam, The Netherlands.
D M J
DM
Oom
Department of Bioinformatics, Erasmus Medical Center, Rotterdam, The Netherlands.
A H J
AH
Koning
Department of Obstetrics and Gynecology, Division of Urogynecology, Erasmus Medical Center, Rotterdam, The Netherlands.
C S
CS
Biesmeijer
Department of Obstetrics and Gynecology, Division of Obstetrics and Prenatal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
E A P
EA
Steegers
Department of Obstetrics and Gynecology, Division of Urogynecology, Erasmus Medical Center, Rotterdam, The Netherlands.
A B
AB
Steensma
D000328:Adult; D000368:Aged; D000465:Algorithms; D003198:Computer Simulation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008875:Middle Aged; D015588:Observer Variation; D056887:Pelvic Organ Prolapse / Q000000981:diagnostic imaging*; D010502:Perineum / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012146:Rest; D014463:Ultrasonography; D014636:Valsalva Maneuver; D055815:Young Adult
3D translabial ultrasound; agreement; levator hiatus; pelvic floor muscles; pelvic organ prolapse; reliability; virtual reality imaging