Three-dimensional contrast medium-enhanced computed tomographic cisternography for preoperative evaluation of surgical anatomy of intradural paraclinoid aneurysms of the internal carotid artery: Technical note

OBJECTIVE AND IMPORTANCE: Precise preoperative evaluation is especially important when internal carotid artery aneurysms in the paraclinoid region are clipped, because these vascular structures are located in close proximity to various important in structures such as the optic nerve and anterior clinoid process. We report a new, method for "simultaneously" describing the interrelationships among the aneurysm, internal carotid artery, optic nerve, and bony structures with three-dimensional. contrast medium-enhanced computed tomographic (3-D CMECT) cisternography. METHODS: Informed consent was obtained from the patient. An 8-ml injection of iotrolan (Isovist; Schering, Berlin, Germarny) (240 mg l/ml) was administered into the lumbar intrathecal space. A computed tomographic scan of the head was obtained 2, hours later with a multislice Asteion computed tomographic scanner (Toshiba, Inc., Tokyo, Japan). An Alatoview workstation (Silicon Graphics, Mountain View, CA) was used to reconstruct the three-dimensional images. RESULTS: These images, as generated by to by 3-D CMECT cisternography, were found to accurately demonstrate the interrelationships of the internal carotid artery, aneurysm, and surrounding structures preoperatively. The findings obtained from these images proved to be quite similar to the intraoperative findings, 3-D CMECT cisternography clarified whether the paraclinoid aneurysm was intradural or extradural. CONCLUSION: 3-D CMECT cisternography was found to provide a useful means for preoperative evaluation of lesions in the paraclinoid area.