Comparison of MR and CT in Patients with Intracranial Aneurysm Clips
CT and MR images of the brain were obtained without complications in 16 patients operated upon for ruptured aneurysms using nonferromagnetic Yasargil Phynox or Sugita Elgiloy clips. These clips were not magnetized and did not move when introduced into our scanner (0.3 T Fonar β-3000 M) in a previous study. The artifacts caused by the clips were smaller on MR than on CT and anatomical structures such as brain stem and temporal lobe were therefore better visualized on MR. Brain tissue lesions corresponding to the frontotemporal surgical approach were seen in seven patients with MR and in six with CT. In three patients temporal lobe lesions seen on MR were not visualized on CT because of beam hardening artifacts. Lesions unrelated to the region of surgery were seen in nine patients with MR and in five with CT. In conclusion, our study shows that patients with nonferromagnetic Yasargil and Sugita clips can safely be examined in a 0.3 T Fonar MR scanner. MR provides more information than CT because of less disturbance of the image by metal artifacts and superior soft tissue discrimination.