Brain shift is the main natural cause of major navigation imprecision. Despite numerous attempts no trials showed a possibility to calculate and predict it's value although some patterns were found. Some modern navigational features allow to partially resolve this problem. Manual shift correction allows to displace brain structures but can only be used if brain shift is linear. Intraoperative computed tomography (CT) and magnetic resonance imaging (MRI) allow to update navigational data but violate surgical workflow and cannot display brain tissue in real time. Intraoperative sonography has poorer quality, limited observe volume and lengthy learning curve.~The purpose of the study is to calculate magnitude, type of intraoperative brain shift and assess possibility of it's prediction.~For each patient a surgeon intraoperatively will assess location of brain surface, various intracranial structures and lesion margins during surgery. Postoperatively these data will be compared to lesion's characteristics, patient's state and intraoperative features.
The purpose of the study is to calculate magnitude, type of intraoperative brain shift and assess possibility of it's prediction.