title: Fetal cardiac interventricular septum: volume assessment by 3D/4D ultrasound using spatio-temporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL).
abstract: OBJECTIVE
  To determine reference values for fetal interventricular septum (IVS) volume by 3D/4D ultrasound using spatio-temporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL).
  
  
  METHODS
  A prospective cross-sectional study was conducted on 200 consecutive normal low-risk pregnant women at a gestational age ranging from 18w0d to 33w6d. The volume data sets of the fetal heart were acquired by applying STIC to a four-chamber plane. IVS volume was calculated offline using VOCAL with rotation of 30° (six planes). To assess the correlation of fetal IVS volume as a function of gestational age (GA), Pearson's correlation coefficient (r) and polynomial regression models with adjustments through the coefficient of determination (R(2)) were calculated. The intra-class coefficient (ICC) was used to evaluate intra- and inter-observer reproducibility.
  
  
  RESULTS
  A good correlation between GA and fetal IVS volume (r = 0.827) was observed. The mean fetal IVS volume ranged from 0.13 ± 0.03 cm(3) (0.08-0.18 cm(3)) at 18wd0 of gestation to 1.33 ± 0.37 cm(3) (0.41-1.98 cm(3)) at 33w6d. The best correlation between fetal IVS volume and GA was exponential: fetal IVS volume = 0.11e(0.139×GA) (R(2 )= 0.785). A good intra- and inter-observer reliability were observed, with ICC = 0.999 and 0.991, respectively.
  
  
  CONCLUSIONS
  Reference values for fetal IVS volume using STIC and VOCAL by 3D/4D ultrasound between 18w0d and 33w6d of gestation were determined and showed to be reliable and concordant.
authors.affiliation: a Fetal Cardiology Unit, Department of Obstetrics , Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP) , São Paulo , SP , Brazil .
authors.forename: Liliam Cristine
authors.initials: LC
authors.lastname: Rolo
authors.forename: Eduardo Felix Martins
authors.initials: EF
authors.lastname: Santana
authors.forename: Priscila Henriques
authors.initials: PH
authors.lastname: da Silva
authors.forename: Fabricio Da Silva
authors.initials: Fda S
authors.lastname: Costa
authors.forename: Luciano Marcondes Machado
authors.initials: LM
authors.lastname: Nardozza
authors.forename: Gabriele
authors.initials: G
authors.lastname: Tonni
authors.forename: Antonio Fernandes
authors.initials: AF
authors.lastname: Moron
authors.forename: Edward
authors.initials: E
authors.lastname: Araujo Júnior
mesh_terms: D003430:Cross-Sectional Studies; D019561:Echocardiography, Four-Dimensional; D019560:Echocardiography, Three-Dimensional / Q000379:methods; D005260:Female; D005318:Fetal Heart / Q000000981:diagnostic imaging*; D005865:Gestational Age; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D015233:Models, Statistical; D015588:Observer Variation; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D062211:Spatio-Temporal Analysis; D016216:Ultrasonography, Prenatal / Q000379:methods*; D054088:Ventricular Septum / Q000000981:diagnostic imaging* / Q000196:embryology*
keywords: Echocardiography; fetus; interventricular septum; reference value; three-dimensional ultrasound