Neuro-ophthalmological and orbital disease: Imaging indications and findings

Learning objectives: to illustrate imaging findings of the main neuro-ophthalmological and orbital diseases. To describe general guidelines for the choice of imaging modality in neuroophthalmology. Background: the purpose of imaging in ophthalmology is to try to detect and localize the lesions along the course of the visual pathways (eye, optic nerve, optic chiasm, optic tract, brain stem, cerebral cortex). Orbital pathologies can be groped into different etiologic processes: congenital, traumatic, inflammatory, vascular, neoplastic. Orbital lesions can be analyzed as to their position in the orbital spaces: intraocular, intraconal, extraconal-intaorbital, extraconal-extraorbital, lacrimal. Imaging findings: We illustrate the spectrum of imaging findings of the main neuro-ophthalmological and orbital diseases with emphasis on differential diagnosis. We summarize general guidelines for the choice of imaging modality in neuroophthalmology. Ultrasonography is the technique of choice for globe lesions. Computed tomography is useful for the evaluation of patients with orbital disease (tumor, trauma, thyroid) and in those with acute intracranial bleeding. MRI best demonstrates diseases of the optic nerve, which include tumours (glioma, meningioma, hemangioma), radiation-induced damage, demyelinating disease, and inflammatory damage. MRI is the study of choice for sellar and parasellar lesions. Angiographic and venographic techniques are required when studying vascular disease (aneurysms, dural venous sinus thrombosis). Functional studies might be useful when structural imaging appears normal despite clinical findings that suggest underlying brain dysfunction. Conclusion: modern neuroimaging modalities play an important role in the management of many neuro-ophthalmological disorders. Accurate communication between radiologist and ophthalmologist is mandatory in order to optimize the prescription and interpretation of imaging in ophthalmology.