Intraoperative evaluation using a multimodality probe of temperature-dependent neurovascular modulation during focal brain cooling.

OBJECTIVE

This study aimed to assess the effects of focal brain cooling (FBC) on human brain tissue through use of multiple sensing techniques by monitoring cerebrovascular activity and brain temperature.

METHODS

Intraoperative brain activity monitoring using a multimodality probe capable of measuring brain temperature, electrocorticography (ECoG) and changes in cerebral hemoglobin concentration was performed in 13 patients with refractory epilepsy. Brain temperature and neurovascular activity were measured beneath and surrounding the FBC device. Data were categorized into three temperature ranges [low-temperature range (LTR, <18 °C), moderate-temperature range (MTR, 18 °C-28 °C), and high-temperature range (HTR, >28 °C)] for analysis.

RESULTS

Changes in oxyhemoglobin (ΔO2Hb) and deoxyhemoglobin (ΔHHb) across the temperature ranges showed a U-shape and inverted U-shape pattern, respectively. ΔO2Hb decreased and ΔHHb increased in the MTR, reflecting enhanced neuronal activity and increased oxygen consumption. Conversely, ΔO2Hb increased and ΔHHb decreased in the LTR, indicating suppressed neuronal activity and reduced oxygen consumption. These findings highlight the temperature-dependent modulation of neurovascular activity by FBC, driven by distinct non-linear patterns.

CONCLUSIONS

FBC selectively influenced brain electrical activity and hemoglobin concentration, highlighting its subtle effects on neurovascular dynamics.

SIGNIFICANCE: These findings provide critical insights into optimizing cooling strategies for neurological disorders using multimodality probes and FBC devices.