Diffusion Restriction in the Optic Nerve and Retina in Patients With Carotid Occlusion.

Objectives: The primary role of magnetic resonance imaging (MRI) in a patient with suspected optic neuropathy is to rule out nonischemic disorders, and many of the reported cases of ischemic optic neuropathy with positive neuroimaging are atypical forms of ischemic optic neuropathy. We studied the role of diffusion-weighted images of MRI in patients with ocular ischemia.

Methods: We describe the clinical, fundoscopic and neuroimaging characteristics of 3 patients with definite ocular ischemia related to occlusion of the carotid artery.

Results: Diffusion-weighted images revealed typical changes of ischemia in a "cup of wine" shape, with increased signal intensity in diffusion-weighted imaging and a decrease in diffusivity in the apparent diffusion coefficient maps. A repeated MRI 8 days after presentation showed persistent hypointensity in apparent diffusion coefficient maps in 1 of the patients.

Conclusions: Patients with ocular ischemia can disclose typical ischemic changes on dedicated brain MRI sequences. These findings might be beneficial in the diagnosis of patients with acute vision loss.