No abstract

We imaged two patients who had silicone oil injected their vitreous cavities. The images demonstrated an increased chemical shift artifact. We developed and tested an in vitro silicone oil model in an attempt to explain this. To our knowledge, this artifact has not been previously described. We constructed a phantom using medication cups containing water, lard and two types of silicone. Background control baths of water and lard were used to simulate different local environments. The phantoms were imaged with T1-and T2-weighted and T1-weighted fat suppression sequences. The artifacts were due to the pronounced chemical shift of silicone in relation to intraconal fat. Our model accurately reproduced our clinical images. Spectral analysis of the silicone model revealed different resonating frequencies for fat/silicone, thereby explaining the pronounced chemical shift artifact.

Two patients with complex aneurysms of the vertebrobasilar system were treated using platinum coils. During these sessions, 22 coils were placed in a basilar tip aneurysm in a 48-year-old woman. Almost total occlusion of the lumen was achieved, excepted in the area from which the right posterior cerebral artery arose. A large fusiform vertebral artery aneurysm in a 6-year-old boy was treated using 16 coils, which partially occluded the lumen at initial embolization. Follow-up angiography 2 weeks later revealed almost complete occlusion of the lumen with preservation of the vertebral artery. Our experience indicates that coil embolization of complex intracranial aneurysms is an acceptable treatment alternative to surgery or to a detachable balloon.

A craniopharyngioma with two unusual manifestations, a dense capsular stain and occlusion of the internal carotid artery, is reported. Neither of these findings appear to have been reported previously. Explanations for these unusual phenomena are offered.