Intraoperative sonography is usially used in neurooncology to detect brain tumors and exclude their remnants. A few studies describe it's usage while removing hematomas or vascular malformations. Ultrasound is the only method allowing to observe brain tissue in real time. It is chip and doesn't violate surgical workflow. Main disadvantages of sonography are lengthy learning curve and poorer image quality compared to magnetic resonance imaging. Novel acoustic coupling fluid, contrast-enhanced ultrasound and elastography expanded it's effectiveness. Meanwhile problems of locating of isoechogenic lesions with poor margins and elimination of artefacts are steel actual.~Objective of the study is to determine possibilities of intraoperative sonography in detecting of various brain mass lesions, assessing extent of their resection and define indications to use ultrasound-guided needle or ultrasound wire-guided port.~A surgeon will intraoperatively locate mass lesion and assess extent of it's resection with sonography. Ultrasound scanning will be performed through the same surgical approach or at a distance through enlarged craniotomy, periodically or permanently. To facilitate approach to subcortical and deep small mass lesions ultrasound-guided needle or ultrasound wire-guided port will be used.
Objective of the study is to determine possibilities of intraoperative sonography in detecting of various brain mass lesions, assessing extent of their resection and define indications to use ultrasound-guided needle or ultrasound wire-guided port.