MR-guided endoscopic sinus surgery.

We describe an interactive, intraoperative imaging-guided method for performing endoscopic sinus surgery (ESS) within a vertically open MR system. The procedure was performed with intraoperative imaging using a 0.5-T magnet with a 56-cm vertical gap. Interactive control of imaging planes was accomplished by optical tracking with two infrared light-emitting diodes mounted on an aspirator probe. The probe's position defined the location of the orthogonal imaging planes. Twelve patients with varying degrees of sinus disease underwent ESS with MR imaging guidance. Patients had acute and chronic sinusitis, nasal polyposis causing airway obstruction, or tumor requiring tissue biopsy. All procedures were performed with the patients under general anesthesia. The integration of endoscopy with optical tracking and intraoperative interactive imaging allowed localization of anatomic landmarks during ESS. No complications were encountered.