Assessment of fetal optic chiasm: an echoanatomic and reproducibility study

Abstract

The hyperechoic structure evident on 2D- and 3D-US, just below the circle of Willis, is indeed the OC. 2D-US is apparently as good as 3D-US for visualization of the OC. However, only measurement of the decussation showed low intra- and interoperator variability, whereas measurement of the optic tract is of questionable variability. As gestation advances between 20 and 30 weeks, the OC becomes more oblique in orientation. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Agenesis of the septum pellucidum: Prenatal diagnosis and outcome

“…Nomograms of the fetal optic tract, including measurements of the optic nerves and optic chiasma, have been published in an attempt to prove that measurements of a normal fetal optic tract decrease significantly the risk of optic tract hypoplasia, but it is evident that these measurements are unable to completely exclude SOD diagnosis . In our study, we had measurements only for part of the cases and the difference between the groups was not statistically significant, although in cases in which it looked normal or abnormal it helped to differentiate between isolated and not isolated cases.…”

“…Data were collected from the US and MR examinations regarding the partial or complete nature of the agenesis, the presence and measurements of the optic nerves and the optic chiasma (measurements were taken according to the previously published articles) and presence of associated CNS and NON‐CNS anomalies. Since there were different centers and examiners can be variations between measurements.…”

How to obtain diagnostic planes of the fetal central nervous system using three-dimensional ultrasound and a context-preserving rendering technology

“…The qualitative evaluation of Crystal Vue™ in the assessment of the fetal CNS and its comparison to multiplanar and MRI highlights different properties for each technique. Multiplanar imaging is a useful modality for evaluation of the fetal CNS (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)63). Crystal Vue™ appears to give high resolution imaging in the assessment of the developing cortical gyri and sulci in the coronal and sagittal planes and for the delineation of the wall of cystic lesions.…”

“…On the other hand, the offline multiplanar navigation of 3D volumes can provide better visualization and recognition of normal fetal anatomy and more accurate definition of fetal abnormalities compared to 2D US (1)(2)(3)(4)(5)(6). For these reasons, this technology has been shown to be helpful for the evaluation of the fetal central nervous system (CNS) (7)(8)(9) and particularly of the posterior fossa (10)(11)(12)(13), the cortical layer (14)(15)(16)(17), midline structures (18)(19)(20) and the optic chiasm (21,22). Additionally, 3D US may provide advantages for the assessment of the face (23,24).…”

Fetal optic chiasm: three steps for visualization and measurement on routine transabdominal ultrasound

“…The critical step is obtaining a rotation angle needed to achieve an adequate image. Paladini et al . described the chiasmocallosal angle which changes as the brain rotates with advancing gestational age.…”