APPLICATION OF CONTRAST-ENHANCED CONSTRUCTIVE INTERFERENCE IN STEADY STATE MAGNETIC RESONANCE IMAGING TO LEKSELL GAMMAPLAN FOR LOCALIZING C2-C3 ANEURYSMS

OBJECTIVE We used gadolinium (Gd)-enhanced constructive interference in steady state (CISS) magnetic resonance imaging with the Leksell GammaPlan (LGP; Elekta AB, Stockholm, Sweden) system for accurate preoperative evaluation of the anatomic localization of intradural and/or extradural C2–C3 aneurysms. METHODS Anatomic localization of 8 unruptured aneurysms of the C2–C3 segment was evaluated using Gd-enhanced CISS imaging with LGP. Four patients diagnosed with intradural aneurysms, 1 with a combined intraextradural aneurysm, and 1 with an intracavernous aneurysm underwent operation. The aneurysmal localizations diagnosed preoperatively by Gd-enhanced CISS imaging with LGP were compared with intraoperative findings. RESULTS By use of Gd-enhanced CISS imaging with LGP, 3-dimensional visualization of the internal carotid artery, aneurysms at the C2–C3 segment, optic nerve, oculomotor nerve, cavernous sinus, and anterior clinoid process was possible in 8 patients. The localization of intradural or combined intra-extradural aneurysms was diagnosed on the basis of the oculomotor nerve and the cavernous sinus depicted in 3-dimensional images. The oculomotor nerve and the cavernous sinus serve as landmarks for the proximal ring on images of the carotico-oculomotor membrane. Intradural or intra-extradural localization of C2–C3 aneurysms with this novel technique was in complete agreement with intraoperative findings in 6 surgical cases. CONCLUSION This study demonstrated the utility of Gd-enhanced CISS imaging used with LGP for accurate preoperative localization of intradural and/or extradural aneurysms at the C2–C3 segments.