Nine of 1468 patients from 2027 procedures were identified. Median age was 75 years (IQR 63-78). 7/9 had hypertension and hyperlipidemia. Six patients underwent aneurysm embolization, one for carotid artery stenting and two diagnostic DSA. Median procedure time was 100 minutes (IQR 91-123). Isovue-300 was used in all except two cases (elevated creatinine) where Visipaque-320 was used (contrast median of 109cc (IQR 100-125cc)). All patients presented elevated intervals of SBP ranging between 150-200 mmHg during the procedure. Mean symptom onset was six hours post-procedure with aphasia (six patients), encephalopathy (five), motor weakness (four), neglect (two) and cortical blindness (two).  

All the patients had head CT performed shortly after the symptoms onset. It demonstrated loss of gray-white matter differentiation (six), sulcal effacement (five) and contrast extravasation (two). CTP demonstrated prolonged MTT with mildly decreased CBF in three patients with patent intracranial vasculature. No laboratory abnormality was found in any of the patients.

EEG performed in 4 patients demonstrated diffuse ipsilateral dysfunction without epileptiform activity. All patients received intravenous fluids and steroids with symptom resolution within 72 hours in 8/9 (88%).

CIN should be considered in the context of progressive onset of neurological deficits after endovascular procedures. A distinct imaging pattern of ipsilateral hemisphere edema in the absent of acute ischemia is usually identified. Uncontrolled procedural hypertension seems to be a predisposing factor for all these patients.