Percentage Amplitude of Fluctuation Alterations in Multiple Frequency Bands in Patients With Transient Ischemic Attack: A Resting-State fMRI Study.

Purpose: This study aims to investigate functional abnormalities in transient ischemic attack (TIA) patients compared to healthy controls (HCs) using percent amplitude of fluctuation (PerAF) across multiple frequency bands derived from resting-state functional magnetic resonance imaging (rs-fMRI). Methods: We scanned 48 TIA patients and 41 HCs using rs-fMRI and high-resolution T1-weighted brain images. Both PerAF and modified PerAF (mPerAF) were utilized for comparative analysis across the typical frequency band (0.01-0.08 Hz) and two subfrequency bands: slow-4 (0.027-0.073 Hz) and slow-5 (0.01-0.027 Hz). Two-sample t-tests were conducted to assess group differences, with multiple comparisons correction using Gaussian random field (GRF) methods. Results: Compared to HCs, TIA patients exhibited significantly lower PerAF in the right inferior frontal triangular gyrus in both the typical and slow-5 bands. Additionally, reductions were observed in the right superior frontal medial gyrus in the slow-4 band and the left middle temporal gyrus in the slow-5 band. No significant differences were observed in mPerAF. Conclusion: These findings suggest a significant impact of TIA on multiple brain regions, with frequency-specific alterations in PerAF, providing novel insights into the underlying mechanisms of TIA.