Assessment of silent embolism from carotid endarterectomy by use of diffusion-weighted imaging: Work in progress

BACKGROUND AND PURPOSE: Transcranial Doppler studies have suggested that mi croemboli are released into the arterial circulation during the majority of carotid endarterectomy (CEA) procedures. This, together with the observati on that neuropsychological performance may decline postoperatively, has led to concern that cerebral infarction may occur unrecognized during CEA, Our objective was to examine this risk with diffusion-weighted imaging, a tech nique that is highly sensitive to acute cerebral infarction, METHODS: Eighteen participants (median age, 68 years; age range, 56-87 year s) were assessed with diffusion-weighted imaging and the National Institute s of Health Stroke Scale before and after CEA, Imaging was performed using single-shot echo-planar imaging with a maximum diffusion sensitivity of b = 1000 s/mm(2) applied to three orthogonal planes. Preoperative imaging was performed a median of 2.5 hours before surgery (range, 0.5-12.5 hours) and 15 hours after surgery (range, 1.5-58.5 hours). Two neuroradiologists indep endently interpreted the diffusion-weighted images, blinded to operative st atus and clinical findings. RESULTS: There was no diffusion-weighted imaging evidence of silent embolis m in this series of 18 participants (95% confidence interval limits, 0 to 1 0%). Clinical complications were confined to one case of confusion occurrin g after CEA; the diffusion-weighted imaging results were normal in this eas e. CONCLUSION: There is no evidence from our series that silent cerebral infar ction is a common occurrence during CEA, These data provide further support for the safety of CEA.