Fig. 4: Bi-exponential model is required to fully describe in vivo measurements.
From: Time-of-flight resolved light field fluctuations reveal deep human tissue physiology
a–c Fitting TOF-resolved field autocorrelations with an empirical bi-exponential 5-parameter model (3 amplitudes, 2 decay rates) reveals the presence of a slow dynamic component. d–f Corresponding TOF-resolved decay rates, and quantitative blood flow indices for the fast dynamic component (BFIfast). Shaded regions represent 95% confidence intervals. g–i Adjusted R2 values support the need for the 5-parameter model to accurately describe iNIRS measurements up to intermediate times of flight of 200–400 ps, depending on the tissue, beyond which a 3-parameter model suffices (two amplitudes, one decay rate). j–l Exemplary field autocorrelations for selected times of flight confirm the need for the 5-parameter model up to intermediate TOFs. Note that with more averaging, a 5-parameter model was needed in the human forehead at even later TOFs (Supplementary Fig. 4).
