Objective: Cerebral hyperperfusion syndrome(CHS) manifests as a collection of symptoms brought on by heightened focal cerebral blood flow, afflicting nearly 30% of patients who have undergone superficial temporal artery(STA)-middle cerebral artery(MCA) anastomosis. The aim of this study was to investigate whether the amalgamation of magnetic resonance imaging(MRI) fluid-attenuated inversion recovery(FLAIR) and apparent diffusion coefficient(ADC) imaging via MRI can discern cerebral hyperemia after STA-MCA anastomosis surgery.
Methods: A retrospective study was performed of patients who underwent STA-MCA anastomosis due to Moyamoya disease or atherosclerotic steno-occlusive disease. A protocol aimed at preventing CHS was instituted, leveraging the use of MRI FLAIR. Patients underwent MRI diffusion with FLAIR imaging 24 h after STA-MCA anastomosis. A high signal on FLAIR images signified the presence of hyperemia at the bypass site, triggering a protocol of hyperemia care. All patients underwent hemodynamic evaluations, including perfusion MRI, single-photon emission computed tomography(SPECT), and digital subtraction angiography, both before and after the surgery. If a high signal intensity is observed on MRI FLAIR within 24 hours of the surgery, a repeat MRI is performed to confirm the presence of hyperemia. Patients with confirmed hyperemia are managed according to a protocol aimed at preventing further progression.
Results: Out of a total of 162 patients, 24 individuals(comprising 16 women and 8 men) exhibited hyperemia on their MRI FLAIR scans following the procedure. SPECT was conducted on 23 patients, and 11 of them yielded positive results. All 24 patients underwent perfusion MRI, but 9 of them showed no significant findings. Among the patients, 10 displayed elevations in both cerebral blood flow(CBF) and cerebral blood volume(CBV), 3 only showed elevation in CBF, and 2 only showed elevation in CBV. Follow-up MRI FLAIR scans conducted 6 months later on these patients revealed complete normalization of the previously observed high signal intensity, with no evidence of ischemic injury.
Conclusion: The study determined that the use of MRI FLAIR and ADC mapping is a competent means of early detection of hyperemia after STA-MCA anastomosis surgery. The protocol established can be adopted by other neurosurgical institutions to enhance patient outcomes and mitigate the hazard of permanent cerebral injury caused by cerebral hyperemia.
Keywords: Cerebral blood flow; Cerebral revascularization; Hyperemia; STA-MCA bypass.