The purpose of this study is to investigate methods to visualize and measure the fetal
optic chiasma (OC) using transabdominal and/or transvaginal two-dimensional (2D) ultrasound
in the coronal plane. The role of analyzing optic chiasma cannot be down scaled in
prognosticating septo-optic dysplasia (SOD) and agenesis of septum pellucidum. This
is a retrospective study of 117 random cases referred for various indications. The
gestational age of the fetuses included in the study was between 19 and 37 weeks.
The OC was visualized and measured in the 2D coronal plane with color Doppler by transabdominal
and/or transvaginal routes. There were 97 normal low risk cases and 19 abnormal cases
in the study. We conclude that it is possible to locate and measure OC width by transabdominal
and transvaginal scans from 19 week onwards. It is possible to get equally good views
by both, transabdominal and transvaginal routes.
Keywords
Optic chiasma (OC) - Two dimension (2D) - Three dimension (3D) - Septo optic dysplasia
(SOD) - Agenesis of corpus callosum (ACC) - Partial agenesis of corpus callosum (PACC)
- Central nervous system (CNS) - Intra uterine growth restriction (IUGR) - Gestational
age (GA) - Magnetic resonance imaging (MRI) - Septum pellucidum (SP)
