Neuroradiologic investigation of the visual system using magnetic resonance imaging.

The aim of this review is to give highlights about technical imaging aspects with which researchers in the neuro-ophthalmologic fields ought to be familiar. After a short overview of history of anatomy of the visual system, a review of the main anatomic details and their corresponding MRI aspects concerning the visual pathways is proposed. Reference lines suitable for MR imaging of the visual system in normal and in diseased states are proposed to orient the neuroradio-ophthalmologic investigations. Brain, cutaneous, and bony landmarks are given to help multimodality imaging approaches, indispensable for anatomofunctional correlations. The neuro-ocular plane is used as the reference for the screening of the visual pathway in its entirety and retained as the orientation of choice for studying orbital optic nerves and eyes. Two other reference lines primarily devoted to temporal lobe imaging, are proposed for the study of the intracranial optic path: the chiasmatocommissural line and the commissural-obex, brainstem axis reference line. Based on brain commissural landmarks present in all vertebrates, these two lines are also helpful in comparative brain anatomic and physiologic studies in vivo as well as in vitro.