ИСТИНА

Objectives: Development of principles for dynamic evaluation of cerebral blood flow (CBF) using intraoperative ASL MRI during surgical revascularization in patients with chronic cerebral ischemia in order to determine indications for additional bypasses. Background: The effectiveness of surgical revascularization in patients with chronic cerebral ischemia directly depends on the degree of restoration of CBF. The current methods do not take into account dynamic changes in cerebral perfusion after the bypass. Intraoperative ASL MRI allows to determine revascularization tactics using single or double bypasses directly during surgical intervention. Methods: From April 2022 to April 2023 in Burdenko Neurosurgical Center 27 patients underwent surgical revascularization (STA-MCA extra-intracranial bypass) with intraoperative MRI. Among them were 14 patients with post-thrombotic occlusion of the internal carotid artery or middle cerebral artery and 13 patients with Moyamoya disease. All patients underwent a comprehensive preoperative MRI study. During the surgical intervention after applying the first bypass intraoperative MRI (DWI, ASL, 3DTOF sequences) was performed in order to determine localization of zones of residual hypoperfusion, to identify signs of local hyperperfusion and to determine indications or contraindications for additional brain revascularization with the second donor branch. In 10 cases, the single bypass was not enough to restore CBF, and a second bypass was performed. Results: In all cases, complete restoration of CBF was achieved in the target areas of the brain. Postoperative MRI, performed on the 1st day after surgery, confirmed the reliability of intraoperative MRI data. In early postoperative period immediate improvement of clinical symptoms was seen in 70%. There were no postoperative complications in any patient. Conclusions: Intraoperative ASL MRI is an effective and useful tool to determine the degree of CBF restoration directly during the surgery that allows to adjust the tactics of surgical treatment and to determine indications or contraindications for the additional revascularization and exclude early ischemic complications.