<title>Application of transcranial cerebral oxygen monitoring during the balloon occlusion test</title>

The purpose of this paper is to evaluate the value of transcranial cerebral oximeter in combination with other monitoring techniques during the balloon occlusion test. In this study 22 patients underwent balloon occlusion testing and were monitored by neurological examination, electroencephalography, transcranial Doppler, and transcranial cerebral oximetry. Eighteen patients had an intracranial aneurysm and four patients had skull base meningiomas. Seventeen patients passed the test without any symptoms. One patient underwent extracranial-intracranial by-pass surgery after failing the first test and passed the second test after the treatment. Transcranial cerebral oximeter showed 10% or less decrease in rSO2 in patients who passed the test and 10% or higher decrease in rSO2 for more than one minute in patients who failed. Electroencephalography and cerebral oximetry are found to be the most dependable monitoring methods for predicting neurological deficits after balloon inflation. Transcranial cerebral oximeter has provided non- invasive monitoring with real-time quantitative information and it was very useful during the balloon occlusion test.