New asymptomatic ischemic lesions on diffusion-weighted imaging after cerebral angiography *
Conventional cerebral angiography（CAG）is relatively low risk for neurological complications. However, diffusion-weighted imaging（DWI）after CAG occasionally reveal an asymptomatic ischemic lesion on the brain. The aim of this study was to investigate the frequency of new asymptomatic or symptomatic DWI lesions after CAG and to clarify the factors associated with them. Fifty-six patients with acute ischemic stroke and transient ischemic attack were prospectively enrolled. Magnetic resonance imaging（MRI）studies including DWI were studied twice, within 48 hours before and after CAG. The following factors were assessed;age, gender, history of stroke, history of ischemic heart disease, vascular risk factors, NIHSS score on admission, stroke subtype, treatment before stroke or TIA（antiplatelets or warfarin）, approach for catheters（transbrachial or femoral artery）, amount of contrast medium used, length of the angiographic procedure, and fluoroscophy time. We divided the patients into two groups according to the presence of new DWI lesions after CAG;Positive group had new DWI lesions, whereas the Negative group had none. After CAG, no patients had new neurological deficits. New asymptomatic DWI lesions were observed in 24 patients（42.9％）. The significant differences observed between two groups were as follows;age（69.8±11.3 for the Positive group versus 61.9±11.3 for the Negative group, p＝0.043）, female（54％versus 28％, p＝0.048）, non-small vessel occlusion（100％versus66％, p＝0.009）, catheter approach for transfemoral artery（63％ versus 13％, p＜0.001）, mean length of the angiographic procedure（63.1±21.6 min versus 43.7±14.2 min, p＜0.001）, mean fluoroscopy time（26.5±13.0 min versus 14.9±5.9 min, p＜0.001）. Sensitivity and specificity analysis to discriminate the positive and negative groups revealed 17 minutes to be the critical threshold point（sensitivity 66.6％ and specificity 68.8％）. Multivariate logistic regression analysis demonstrated that a fluoroscopy time over 17 minutes was an independent factor associated with new DWI lesions after CAG（OR, 9.355, 1.800 to 48.626, p＝0.0078）. After CAG, new asymptomatic DWI lesions were present in 42.9％. Attention should be paid procedures short to avoid the occurrence of brain ischemia.（Accepted on July 20，2006）
