Cortical Blindness, Transient and Otherwise, Associated with Detachable Coil Embolization of Intracranial Aneurysms

Abstract

BACKGROUND AND PURPOSE:Cortical visual loss is a rare complication of cerebral angiography without a definitive pathophysiology. Given the rapid increase in endovascular procedures used to treat cerebral aneurysms, we explored the prevalence of this complication and whether we could add to the understanding of this disorder.

Repeated Injection of Contrast Medium Inducing Dysfunction of the Blood-Brain Barrier

“…In our case, administration of only 72 ml of contrast medium was sufficient to cause toxicity, dysfunction of the BBB, and changes in the brain. 4,8) This unusual case of contrast medium inducing dysfunction of the BBB in the anterior circulation during coil embolization of an intracranial unruptured aneurysm was confirmed by repeated CT, MR imaging, and single-photon emission computed tomography. Tolerance to toxicity of contrast medium probably depends on the individual patient, but repeated injection of contrast medium may cause dysfunction of the BBB, pass through the BBB, and lead to toxic changes directly in the brain.…”

“…9) If the toxicity is too high, changes in the brain may be irreversible. 4,5) We cannot explain why the convulsion occurred during the procedures. Indeed, abandoning the procedures and performing immediate CT to confirm absence of intracranial hemorrhage might be an option, but partial embolization of the aneurysm might also lead to aneurysm rupture or parent artery occlusion, and will probably limit subsequent treatment.…”

“…In cases of systemic administration of contrast medium (350 or 370 mg/ml), a total of 300 to 400 ml contrast medium was administered within a few minutes, 2) whereas in cases of coil embolization, a total of 50 to 300 ml contrast medium (300 mg/ml) was injected selectively within a few hours. [3][4][5] In cases of systemic administration, 300 ml or more contrast medium may be the threshold level of toxicity, whereas in cases of intracranial selective injection, a smaller volume may cause toxicity for the BBB, although the toxic tolerance of the BBB depends on the individual patient. 8) Therefore, the range to cause toxicity is from 50 ml to 300 ml of contrast medium.…”

“…Contrast medium is known to carry the risk of inducing dysfunction of the blood-brain barrier (BBB) in posterior circulation after coil embolization, [3][4][5] but few cases in the anterior circulation have been confirmed by computed tomography (CT), magnetic resonance (MR) imaging, and single-photon emission computed tomography. 8) We report an unusual case of a patient with probable dysfunction of the BBB induced by repeated injection of contrast medium.…”

Confirmation of a Diagnosis by CSF Analysis in a Case of Symptomatic Contrast-induced Encephalopathy with an Onset Immediately after Coil Embolization of an Unruptured Cerebral Aneurysm

“…There have also been reports that angiography performed before and after an episode of contrast-induced encephalopathy did not induce symptoms. 12,13) In our patient, a relatively large amount of contrast agent (210 ml) was used, and the possibility that the temporary right hemiplegia observed immediately after the first session was contrast-induced encephalopathy cannot be excluded. Although contrast-induced encephalopathy is considered to be a specific response to a contrast agent, its causation has not been clarified.…”