[Cerebral complications induced by neurotoxity of nonionic contrast medium after embolization of unruptured cerebral aneurysms: report of 2 cases]

We successfully performed endovascular coil embolization for 2 patients with unruptured saccular aneurysms. However, transient cortical blindness and generalized seizure associated with CNS neurotoxity of contrast medium were noted for each patient after the procedure. In the first case of a 62-year-old woman with a right BA-SCA aneurysm, she complained of blindness with restlessness one day after the intervention but no evidence of embolism on MRA. Abnormal EEG with slow, large amplitudes and 99mTc-HMPAO SPECT-evidenced hyperperfusion were observed in the occipital area. Accompanied by resolution of the edematous changes on MRI in conjunction with normalization of EEG and rCBF by anticonvulsant administration, her visual acuity completely recovered 8 days after the onset. According to these findings, we considered this case as transient cortical blindness. In the second case of a 68-year-old man with a left MCA aneurysm, he exhibited generalized seizure 8 hours after the procedure. CT scan revealed retention of the contrast medium over the left hemisphere. Postictal EEG one day after the seizure showed left frontal slowing but had no evidence of contrast medium retention or hyperperfusion. He recovered well with corticosteroid, anticonvulsant, and intravenous hydration. His follow-up DSA 2 years after the coiling was performed without trouble by reducing the amount/concentration of the contrast medium and by prophylactic steroid and hydration. Non-ionic contrast medium-related neurotoxity as represented by transient cortical blindness or generalized seizure should be recognized as a possible complication of endovascular surgery where patients' brain areas are locally vulnerable to contrast medium exposure.