Prenatal ultrasonic research of fetal optic chiasma / 中华超声影像学杂志

ABSTRACT

Objective To research fetal optic nerve,optic chiasma and optic tract size using high resolution prenatal ultrasound,establish a scan method and the reference range of optic nerve,optic chiasma and optic tract in normal fetus.Methods Based on the section of circulus arteriosus cerebri,the probe were rotated to get the chiasma section for measuring the diameter of bilateral optic nerve,optic tract and area of optic chiasma in 453 normal fetus respectively.Used gestation age and corresponding biological parameters as independent variables,the regression equation was established analyse the gender differences.Results 26-33 weeks was the preferable gestational age to visualize the chiasma section.It had good repeatability except chiasma area.The bilateral optic nerve and optic tract diameter,optic chiasma diameter and area had an increased along with the gestational age reposefully.There was no significant difference between the two sides of optic nerve and the gender.Conclusions Prenatal ultrasound can assess the size and shape of fetal optic nerve,optic chiasma and optic tract.The normal reference range,established by ultrasound,is helpful to diagnose the abnormality of optic chiasma.