OBJECTIVE AND IMPORTANCE:Coil embolization of wide-necked aneurysms is currently difficult, when using a conventional endovascular approach without resorting to complex adjunctive techniques.CLINICAL PRESENTATION:A 41-year-old woman with a history of systemic lupus erythematosus and hypertension refractory to treatment presented with an unruptured right ophthalmic segment aneurysm of the internal carotid artery having an unfavorable neck-to-fundus ratio.INTERVENTION:A new type of Guglielmi detachable coil (Target Therapeutics, Fremont, CA), consisting of a series of omega loops, spontaneously forms a three-dimensional cage after deployment and was used to successfully treat the aneurysm, which was angiographically stable at the 3-month follow-up.CONCLUSION:The new Guglielmi detachable coil may be useful in the embolization of aneurysms having an unfavorable geometry, which would otherwise not be amenable to endovascular treatment without adjunctive techniques.