fNIRS Monitoring During Mechanical Thrombectomy for Outcomes Prediction

Mechanical thrombectomy (MT) is a standard solution to remove the blood clots in the large cerebral arteries when an ischemic stroke occurs. During MT, digital subtraction angiography (DSA) is applied to identify the blood clots and characterize the restoration of the blood flow. However, the hemodynamic changes of various cortices, which is closely related to multiple functions, often are not monitored simultaneously. Functional near-infrared spectroscopy (fNIRS) is a proper wearable neuroimaging technique to monitor the hemodynamic status in real-time. In this paper, the fNIRS signals of the channels covering affected and unaffected cortices of a patient with left middle cerebral artery occlusion are recorded pre-, peri- and post-MT. The variances of the fNIRS signal are expressed using the standard deviation (STD). It is shown that before MT, the STD of the channels over affected cortices is larger than that of the channels over the unaffected cortices. In addition, the STD of the signals over affected cortices decreases gradually after the recanalization. Moreover, the STD of the affected channels only becomes similar to that of the unaffected channels forty seconds after recanalization. To conclude, the STD of the fNIRS signal suggesting the hemodynamic status of the cortices is associated with the stenosis or occlusion conditions of the large cerebral arteries. Therefore, STD of fNIRS signals can be a biomarker to predict the outcome of MT.