Fetal echocardiography: z-score reference ranges for a large patient population

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Name Diagnosis Date ID#
Z-Score Input
FL (mm) MENS AGE BPD (mm)    
   
Aortic Valve (mm) Pulmonary Valve ( mm) Left Ventricle (mm) Right Ventricle (mm) Circumference (mm)

Z-Score Results
Z-Scores Aortic
Valve
Pulmonary
Valve
RV LV Cirumference
FL
MA
BPD

Aortic valve-end systolic diameter

  Fetal Size/Age   Aortic Valve   Z-Score
FL
BPD
MENSTRUAL AGE

Pulmonary valve end-systolic diameter

  Fetal Size/Age   Pulmonary Valve   Z-Score
FL
BPD
MENSTRUAL AGE

Left Ventricular end-diastolic diameter

  Fetal Size/Age   LV End-Diastole   Z-Score
FL
BPD
MENSTRUAL AGE

Right ventricular end diastolic diameter

  Fetal Size/Age   RV End-Diastole   Z-Score
FL
BPD
MENSTRUAL AGE

End-Diastolic cardiac circumference

  Fetal Size/Age   Heart Circum   Z-Score
FL
BPD
MENSTRUAL AGE

   

Lee, W., T. Riggs, et al. (2010). "Fetal echocardiography: z-score reference ranges for a large patient population." Ultrasound Obstet Gynecol 35(1): 28-34.

Ultrasound Obstet Gynecol 2010; 35: 28–34 Published online 15 December 2009 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.7483

Fetal echocardiography: z-score reference ranges for a large patient population

W. LEE*, T. RIGGS†‡, V. AMULA†, M. TSIMIS§, N. CUTLER†, R. BRONSTEEN* and C. H. COMSTOCK*

*Department of Obstetrics and Gynecology, William Beaumont Hospital, †Department of Pediatrics, Beaumont Children's Hospital and ‡Division of Biostatistics, Beaumont Research Institute, Royal Oak and §Wayne State University School of Medicine, Detroit, MI, USA

ABSTRACT
OBJECTIVES: The main goal was to develop new z-score reference ranges for common fetal echocardiographic measurements from a large referral population.
METHODS: A retrospective cross-sectional study of 2735 fetuses was performed for standard biometry (biparietal diameter (BPD) and femoral diaphysis length (FDL)) and an assessment of menstrual age (MA). Standardized fetal echocardiographic measurements included aortic valve annulus and pulmonary valve annulus diameters at endsystole, right and left ventricular diameters at end-diastole, and cardiac circumference from a four-chamber view of the heart during end-diastole. Normal z-score ranges were developed for these echocardiographic measurements using MA, BPD and FDL as independent variables. This was accomplished by using first standard regression analysis and then weighted regression of absolute residual values for each parameter in order to adjust for inconstant variance.
RESULTS: A simple, linear regression model was the best description of the data in each case and correlations between fetal cardiac measurements and the independent variables were excellent. There was significant heteroscedasticity of standard deviation with increasing gestational age, which also could be modeled with simple linear regression. After this adjustment, the residuals conformed to a normal distribution, validating the calculation and interpretation of z-scores.
CONCLUSION: Development of reliable z-scores is possible for common fetal echocardiographic parameters by applying statistical methods that are based on a large sample size and weighted regression of absolute residuals in order to minimize the effect of heteroscedasticity. These normative ranges should be especially useful for the detection and monitoring of suspected fetal cardiac size and growth abnormalities. Copyright  2009 ISUOG. Published by John Wiley & Sons, Ltd.