Surface-based preoperative CT/MRI to intraoperative face scan
registration: a clinical study

L. Joskowicz, R. Shamir, M. Freiman, The Hebrew Univ. of Jerusalem,Y. Shoshan F. Umansky, Hadassah Univ. Hosp., Jerusalem, E. Zehavi, Mazor Surgical Technologies,
Caesarea.

Abstract. We present a clinical study of surface-based registration between a preoperative CT/MRI of a patient head and an intraoperative surface scan of his face. The study was conducted on 14 patients that underwent neurosurgery with standard Neuronavigation based on preoperative CT/MRI datasets. Intraoperatively, before the surgery started, surface scans of the patient faces were acquired with a surface scanner. After extracting face surface points in the upper region of the face from both datasets, the resulting point sets were aligned with a robust two-step rigid registration algorithm. The mean face registration error was 0.9mm (std=0.35mm). The mean estimated target registration errors at 60, 105, 150mm from the face surface were 2.0mm, 3,2mm, 4.5mm. These results indicate that surface-based face registration is clinically viable.

Keywords: surface-based rigid registration, neurosurgery, registration error