The detection of volatile organic compounds (VOCs) in exhaled breath has emerged as one of the most promising non-invasive diagnostic methods in the medical field. In this study, a highly sensitive real-time exhaled methane (CH 4 ) detection system based on tunable diode laser absorption spectroscopy (TDLAS) technology was developed, and the correlation between gut microbiota metabolites and neurological diseases was investigated. The TDLAS system utilized a 3.334 μm mid-infrared laser with a 60-meter optical path Herriott cell, achieving a parts-per-billion (ppb)-level detection limit. The study employed a support vector machine (SVM) algorithm to construct a classification model. Exhaled breath from healthy controls and patients with transient ischemic attack (TIA), multi-cerebral infarction (MCI), acute cerebral infarction (ACI) was analyzed, and revealed significantly higher CH 4 concentrations in the patient groups (p < 0.05), among which the TIA group exhibited the highest concentration. This study confirms that exhaled CH 4 detection can serve as a non-invasive screening tool for cerebrovascular diseases and provides a new technological platform for research on the gut-brain axis mechanism. These findings hold significant clinical value for the early diagnosis and intervention of neurological disorders.
Song et al. (2026) studied this question.