Intraoperative imaging in a comprehensive neuronavigation environment for minimally invasive brain tumour surgery

Development of an image-guided operation theatre offering multimodal information for mini-invasive neurosurgical brain tumour operations.

A multi-purpose resistive low-field MR scanner with on-off capability, was installed in a radio frequency-shielded operating room with in-room control panel and display. Intraoperative ultrasound imaging with Doppler mode as needed is used to provide check-up image data between intraoperative MR-imaging sessions. Cortical stimulation and registration are performed during awake craniotomies. The neuronavigation systems are customised arm-based and passive optical. The navigation systems show the positions of the ultrasound probe, cortical stimulation electrode, biopsy needles, endoscope and other instruments on the intraoperative MR-images.

Since 1999, 70 patients (mean age 47, range 3-88 years) have been operated with intraoperative MR-guidance (including 10 tumour biopsies, 56 resections). Twenty-one patients (mean age 46, range 16-67 years) underwent awake craniotomy and tumour resection secured with cortical stimulation and usually preoperative fMR-imaging. The present operating environment offered useful multimodal information for surgery of brain tumours in critical locations. Surgical mortality was 0%, morbidity included 3 (4.3%) infections and 2 (2.9%) permanent hemiparesis. Further removal of tumour was continued in 17 cases (57%) out of the 30 cases where intraoperative MR imaging was used for controlling completeness of the resection.