Silent embolism in diagnostic cerebral angiography: detection with diffusion-weighted imaging

Angiography has known and documented risks of neurological events. We prospectively studied 20 patients who underwent diagnostic cerebral angiographic examinations and diffusion-weighted MRI (DWI). Eighteen patients had DWI before and after their angiogram, whereas two patients had a DWI only after their angiogram (DWI was normal in both of these patients). No clinical neurological deficits were detected in any of our patients after angiography, but in three of 20 patients there was a new hyperintense signal abnormality found on DWI. Diffusion-weighted MRI provides an objective means of detecting both clinical and subclinical neurological events. Diffusion-weighted imaging might therefore provide an easier method of assessing complication rates in cerebral angiography by reducing the number of patients required for meaningful statistical analysis.