title: Reference ranges for the fetal cardiac circumference derived by cardio-spatiotemporal image correlation from 14 to 40 weeks' gestation.
abstract: OBJECTIVE
  The purpose of this study was to construct reference ranges for the fetal cardiac circumference derived from volume data sets obtained by cardio-spatiotemporal image correlation.
  
  
  METHODS
  A prospective descriptive study was conducted on normal singleton pregnancies with certain dates from 14 to 40 weeks' gestation. All underwent cardio-spatiotemporal image correlation to acquire volume data sets for subsequent analysis. Cardiac circumferences were measured offline in a multiplanar view with 4-dimensional imaging software. The reference ranges were constructed against gestational weeks and the biparietal diameter as independent variables, using regression models for both the mean and SD.
  
  
  RESULTS
  A total of 678 satisfactory volumes were analyzed. Normal reference ranges for predicting means and SDs of the fetal cardiac circumference were established based on best-fitted equations. The mean cardiac circumference (millimeters) was modeled as a function of gestational age (weeks) and biparietal diameter (centimeters) as follows: cardiac circumference = -53.11 + 6.56 × gestational age - 0.035 × gestational age(2) (SD = 0.67 + 0.18 × gestational age) and -17.60 + 17.68 × biparietal diameter (SD = 1.651 + 0.61 × biparietal diameter). Equations for z score calculation were also provided, and percentile charts for predicting the cardiac circumference at various points of gestational age and biparietal diameter were constructed.
  
  
  CONCLUSIONS
  Normal reference ranges and z scores for the fetal cardiac circumference have been provided. These normative data may be useful tools for assessment of fetal cardiac size, especially in cardiomegaly due to fetal anemia.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Kuntharee
authors.initials: K
authors.lastname: Traisrisilp
authors.forename: Fuanglada
authors.initials: F
authors.lastname: Tongprasert
authors.forename: Kasemsri
authors.initials: K
authors.lastname: Srisupundit
authors.forename: Suchaya
authors.initials: S
authors.lastname: Luewan
authors.forename: Theera
authors.initials: T
authors.lastname: Tongsong
mesh_terms: D000293:Adolescent; D000328:Adult; D019561:Echocardiography, Four-Dimensional / Q000379:methods*; D005260:Female; D006321:Heart / Q000196:embryology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D009929:Organ Size; D011247:Pregnancy; D011446:Prospective Studies; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*