Abstract
Thirty-two patients who underwent surgery for intracranial aneurysm (clipping with non-ferromagnetic Sugita's clip in 30 and wrapping in two) were studied by MRI and the findings were compared with those of CT. On MRI, the artifacts around the clip consisted of a central signal void and a peripheral rim of increased signal intensity, but they were much smaller than those on CT. MRI apparently was superior to CT in delineation of associating lesions such as lacunar infarction, intraparenchymal hemorrage or periventricular edema. Although the size of ischemic area due to vasospasm and the sensitivity of detecting it on MRI were not different from those on CT, MRI provided figures with better contrast. An increased number of lacunar infarctions in deep cerebral white matter and/or basal ganglia were detected in the post-operative MRI, seemingly due to vasospasm. On the serial MRI, no consistent findings were found in the chronological changes of signal intensities in the subarachnoid space.
