Fetal echocardiography. V. M-mode measurements of the aortic root and aortic valve in second- and third-trimester normal human fetuses.

The aortic root dimension and aortic valve excursion of 43 normal fetuses were recorded with M-mode echocardiography and the measured dimensions correlated with noncardiac measurements (biparietal diameter, head circumference, abdominal circumference, and femur length) and cardiac measurements (diastolic biventricular inner dimension, diastolic left ventricular internal dimension, and mitral valve excursion). The correlation coefficients for the aortic root dimension ranged between 0.87 and 0.95, while those for the aortic valve excursion ranged between 0.78 and 0.87. Regression analysis demonstrated that the best fit of the data was a linear model from which the 5% and 95% confidence limits were computed for individual predictions of aortic root dimension and aortic valve excursion from noncardiac and cardiac measurements.