Intraoperative fusion of field images with CT/MRI data by means of a stereotactic mechanical arm.

In this paper we describe a neurosurgical articulated arm used as a pointer and as a support for intraoperative image acquisition, integrated with a graphic 3-D rendering system. The patient's anatomy is volumetrically displayed, from stereotactically acquired CT, MRI, and DSA images; the head holder is the common reference system for image reconstruction and for the calibration of the surgical arm. Arm orientation in stereotatic space is displayed, together with the surgical arm. Arm orientation in stereotatic space is displayed, together with the volumetric reconstruction of cerebral lesions and surrounding healthy tissue. The arm, equipped with fail-safe electromagnetic brakes, can be employed to support imaging sources such as an endoscope, an echographic probe, or a CCD camera, whose images can be stereotactically integrated with preoperative data in performing minimally invasive neurosurgical procedures.