Abstract
Purpose::
To evaluate a new method of fetal age estimation based on orbital measurement and including the pathologic condition of the fetus.
Methods::
Six orbital and one facial CT-Scan measurements were taken on 71 fetuses ranging from 14 to 41 weeks of gestational age. A full evaluation including radiographic, karyotypic, gross anatomic, and histologic examination of the fetus identified 48 as non dysmorphic, the remaining fetuses were abnormal and presented the same abnormal karyotype (47 + 21 : Down syndrome). A multiple linear stepwise regression, combining these variables (orbital measurements and T21 parameter), was realized to estimate fetal age. The relationship between orbit and trisomy 21 was established by logistic regression. The anatomy/imagery correspondence was evaluated comparing our result to those obtained by direct bone measurement on same fetuses.
Results::
Trisomy 21 parameter is not conserved in the final age determination model. No statistically difference was found between CT scan and bony measurements. One parameter including facial measurement seems to be particularly linked with trisomy 21.
Conclusions::
In this study, trisomy 21 doesn’t appear as a significant fetal age determination influencing factor. CT scan measurements present a good radio-anatomy correspondence and offer an interesting alternative to direct bone measurement. Some measurement could have medical implication for Down’s syndrome prenatal diagnosis.
Keywords: orbit • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • pathology: human