title: Is curved three-dimensional ultrasound reconstruction needed to assess the warped pelvic floor plane?
abstract: OBJECTIVE
  Caudal distension of the female pelvic floor is common and results in perineal descent and a caudally curved levator hiatus (warping). Image reconstruction of the pelvic floor using currently available ultrasound techniques involves a linear approach (flat-plane reconstruction). We aimed to evaluate the feasibility, reproducibility and potential usefulness of a new three-dimensional (3D) technique capable of reconstructing a curved plane of the levator hiatus.
  
  
  METHODS
  Primiparous women were recruited to undergo a 3D/four-dimensional transperineal ultrasound examination 3-6 months after delivery. Levator ani muscle warping was evaluated on Valsalva maneuver by measuring the distance between the plane extending from the pubic rami to the anorectal angle and the plane of minimal hiatal dimensions on the coronal plane. Warping distance was used to reconstruct a curved plane of the levator hiatus using the curved OmniView volume contrast imaging (VCI) technique (C-OV). Intra- and interobserver reproducibility of the C-OV technique were assessed, as was intermethod agreement between the C-OV technique and the linear OmniView-VCI (L-OV) technique, for the measurement of levator hiatal area on Valsalva maneuver.
  
  
  RESULTS
  Measurement of the levator hiatal area using C-OV was feasible in all 84 women recruited. The warping distance ranged from -3.5 to 9.7 mm, confirming that the 1-2-cm slice thickness traditionally used for linear reconstruction was adequate for proper assessment of levator hiatal area in our population. C-OV showed excellent intra- and interobserver reproducibility, as well as excellent agreement with the L-OV technique for measuring levator hiatal area. No systematic difference was demonstrated in any of the reproducibility studies performed.
  
  
  CONCLUSIONS
  3D reconstruction of the warped levator hiatal plane is feasible and highly reproducible. In our population, reconstruction of a curved plane to correct for levator hiatal warping did not offer any benefit over the traditionally performed linear reconstruction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-9322-2184
authors.initials: A
authors.lastname: Youssef
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cavalera
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.|Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pacella
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Salsi
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Morganelli
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Montaguti
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Cataneo
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pilu
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Rizzo
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D010298:Parity; D017773:Pelvic Floor / Q000000981:diagnostic imaging*; D056887:Pelvic Organ Prolapse / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D014636:Valsalva Maneuver
keywords: contrast-enhancing technique; pelvic floor; pelvic organ prolapse; three-dimensional ultrasound; warping