Cortical blindness due to osmotic disruption of the blood-brain barrier by angiographic contrast material: CT and MRI studies.

Numerous experimental studies have demonstrated disruption of the blood-brain barrier by the hyperosmolar, iodinated contrast agents in common use for intravascular injection during radiologic studies. We report 4 cases in which cortical blindness occurred after cerebral angiography. The patients underwent x-ray CT within 1 hour. CT showed abnormal contrast enhancement in the occipital regions in all 4 instances. Two patients underwent MRI; 1 of these manifested abnormal high-signal intensity in the occipital lobes on T2-weighted images. Only 2 previous cases documenting immediate contrast enhancement within the brain substance on CT following angiography are in the literature.