Abstract: This document discusses an exovascular approach to treating an aneurysm using a minimally-invasive instrument guided by magnetic resonance imaging (MRI), computed tomography (CT), or another suitable imaging device. A trajectory guide entry device assists in targeting the aneurysm and determining the proper trajectory thereto. Examples of the aneurysm treatment device include a clip, a clasp, a snare, a loop, a hook, a staple, and an electrocautery or other electrode, or any combination of such devices. The aneurysm treatment device is delivered by a probe, such as a tube or other catheter.

Abstract: A medical device is provided comprising a MRI compatible cranial drill having a removable sterilizable drill bit and a sterile barrier. The sterile barrier has an interior portion, a proximal end, a distal end, a proximal opening at the proximal end and an opening at the distal end. The opening at the distal end further comprises an aperture. The drill is insertable into the proximal opening, the aperture being constructed and arranged to seal around the drill bit such that the drill is enclosed in the interior portion of the sterile barrier and only a portion of the sterile drill bit extends exteriorly of the barrier. In one embodiment, the medical device includes a MRI compatible adjustable depth stop which limits and defines depth of penetration of the drill.