Korotkevich À.*, Ermolaev Yu.**
* Railway Clinical Hospital, Irkutsk, Russia;
** Irkutsk State Institute Of Postgraduate Medical Education, Irkutsk, Russia
Use of intraoperative ultrasonic navigation in the neurosurgical department of the Road Clinical Hospital started in 1990. There were 149 cases (95 males and 54 females), operated for intracerebral hematomas and focal contusions (46), meningeal-vascular and glial tumors (77), intracerebral cysts (15) and brain abscesses (11). Ultrasonic scanning was carried out via dura or on the open brain with application of ALOKA-500 and SHIMADZU SDL-310 apparatus. The method of examination consisted in rotation and change of a sensor dip angle in different planes for obtaining a distinct image of a falx, lateral ventricles, a mass and its spread, a zone of perifocal edema.
Intracerebral hematomas looked like a negative mass with a perifocal hyperechogenic zone, whereas focal contusions were represented by a hyperechogenic zone with rather homogenous density. Meningeal-vascular cerebral tumors manifested themselves as hyperechogenic round structures, delimited from the brain and having a zone of perifocal edema. Glial tumors were not hyperechogenic; there was a wide zone of edema in malignant neoplasms. A borderline between a tumor and the brain was absent rather often. Intracerebral cysts were visualized as homogenous echogenic formations. Brain abscesses looked like round objects with a heterogeneous echo; their cavities had a hyperechogenic content. They were surrounded by a capsule of a different thickness with a zone of perifocal edema. All this information, as well as neurovisualization, allowed to achieve more exact intraoperative localization of a pathologic process even in the absence of up-to-date navigation systems.