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

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 0.9 mm (STD 0.35 mm). The mean estimated target registration errors at60, 105, 150 mm from the face surface were 2.0, 3.2, 4.5 mm. These results indicate that surface-based face registration is clinically viable.