Images of the optic nerve: anatomic-CT correlation

Area of Science:

• Ophthalmology
• Radiology
• Neuroanatomy

Background:

• The intraorbital optic nerve's complex, sinuous course presents challenges in imaging interpretation.
• Accurate assessment of optic nerve anatomy is crucial for diagnosing various ophthalmic and neurological conditions.

Purpose of the Study:

• To correlate the anatomical course of the intraorbital optic nerve with its appearance on computed tomographic (CT) images.
• To analyze and explain discrepancies between anatomical and CT findings of the optic nerve.

Main Methods:

• Analysis of anatomical sections of the optic nerve in various planes.
• Correlation of anatomical findings with corresponding computed tomographic (CT) images.
• Evaluation of optic nerve appearance on reformatted CT images based on original section planes.

Main Results:

• The optic nerve exhibits a sinuous course in both horizontal and vertical planes.
• No single thin axial or sagittal CT section can be perfectly parallel to the optic nerve.
• Oblique transsection of the optic nerve on CT leads to apparent hypodensity or "thinning" of segments.
• The appearance of the optic nerve on reformatted CT images is dependent on the original CT section plane.
• CT scans of the eye in primary position may not allow reliable judgments of optic nerve course and size.

Conclusions:

• Apparent "thinning" or hypodensity of the optic nerve on CT is an artifact of oblique imaging planes.
• Understanding these imaging artifacts is essential for accurate interpretation of optic nerve CT scans.
• CT imaging of the optic nerve requires consideration of sectioning planes to avoid misinterpretation of its true anatomy.