title: Use of three-dimensional (3D) sonography to assess the true midsagittal plane of fetal spine.
abstract: OBJECTIVE
  To study the angle of the deviation of a presumed midsagittal plane of the fetal spine from the true midsagittal planes by three-dimensional (3D) ultrasound and to investigate whether the experience of operators has an effect on the degree of this deviation.
  
  
  METHODS
  Eight sonographers, four were trained to perform routine anomaly scan (Trained Group) and four were trained to perform fetal biometric measurement only (Non-trained Group), were asked to use a 3D transducer to obtain a 2D image which they thought to represent the true midsagittal plane of the fetal spine. A 3D volume was then acquired. Stored volumes were analyzed using the multiplanar mode. In the transverse plane, the angle of the deviation of presumed midsagittal planes from the true midsagittal planes was measured.
  
  
  RESULTS
  The mean angle of deviation of the trained group was significantly lower than that of the non-trained group (7.9 vs. 21.1, p < 0.001). There were no significant variations among the four operators within each group. However, even among the Trained Group, the angle of deviation could be as large as 27.2°.
  
  
  CONCLUSIONS
  Training improved the ability to obtain a midsagittal plane of the fetal spine. 3D ultrasound might provide potential useful information to guide the acquisition of standard image planes.
authors.affiliation: Fetal Medicine Unit, Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
authors.forename: Xiao Hong
authors.initials: XH
authors.lastname: Yang
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Tak Yeung
authors.initials: TY
authors.lastname: Leung
authors.forename: Sau Mei
authors.initials: SM
authors.lastname: Wong
authors.forename: Tze Kin
authors.initials: TK
authors.lastname: Lau
mesh_terms: D000328:Adult; D001699:Biometry; D019521:Body Patterning / Q000502:physiology; D001837:Body Weights and Measures; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000706:statistics & numerical data; D007746:Labor Presentation; D015588:Observer Variation; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011361:Professional Competence / Q000706:statistics & numerical data; D013131:Spine / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000196:embryology*; D016216:Ultrasonography, Prenatal / Q000379:methods* / Q000706:statistics & numerical data