Neurosurgery for functional disorders guided by multimodality imaging

This paper presents a procedure for combining MR anatomical information and a stereotactic reference obtained from a CT study with a Leksell frame attached to the patient’s head, in order to guide neurosurgery of functional disorders. MRI acquisition can be performed well before the surgery, without the stereotactic frame. The day of the intervention, after attaching the Leksell frame to the patient, a CT image (1.5 mm slices) is acquired. This study will provide the stereotactic reference and includes only the part of the brain where the disorder is located. Before surgery, physicians register the MRI with the CT using a procedure based on an automated algorithm (Mutual Information) and visually check the result. MRI is used to locate the target in the brain, while the frame visible in the CT allows to calculate the stereotactic 3D coordinates. Frame references are located on the MRI image allowing to calculate Leksell coordinates of any given point. When the exact position of relevant structures has been recorded, the physicians proceed with the surgery. The protocol has been tested in ten patients, showing a positive surgical outcome with a significant decrease of the functional disorders. The method has proved to be accurate enough, avoiding the use of stereotactical frames during the MR acquisition and making the clinical procedure simpler and faster.