Fig. 1. Applications of dynamic change of light field amplitude in OCT functional imaging. (a) Angiography^[29]; (b) 3D velocimetry^[30]; (c) tissue-specific imaging^[31]; (d) thermometry^[28]

Fig. 2. Illustration of dynamic changes in OCT amplitude due to microscopic movements in an organism

Fig. 3. Different types of scanning (spatiotemporal sampling) protocols for acquiring dynamic changes in OCT light field amplitude. (a) MB scanning; (b) BM scanning; (c) bidirectional scanning; (d) frame-by-frame volumetric scanning; (e) intervolume scanning; (f) Lissajous scanning^[49]

Fig. 4. Data analysis methods for extracting functional information from dynamic change of OCT light field amplitude. (a) Dynamic light scattering-based method; (b) power spectrum-based method

Fig. 5. Examples of new techniques and applications in OCTA. (a) Visible-light OCTA to measure retinal capillary blood oxygenation^[66]; (b) ultra-wide-field-of-view high-sensitivity OCT for finger capillary imaging^[67]; (c) subcutaneous microvasculature of the GI tract acquired by an ultra-high-speed endoscopic OCT probe^[69]; (d) handheld OCTA for the diagnosis and treatment of retinopathy of prematurity^[71]

Fig. 6. Application examples of three-dimensional blood flow velocity measurement using dynamic light scattering OCT. (a) Measurement of blood flow velocity using dynamic light scattering OCT in B-scan mode (red) compared with results using Doppler OCT and M-scan mode^[75]; (b) quantitative imaging of cerebral blood flow velocity^[77]

Fig. 7. Examples of technical realization schemes for dynamic OCT. (a) BM scanning mode + spectrum-based analysis method^[57]; (b) intervolume scanning mode + combination of spectrum-based and dynamic light scattering-based analysis methods^[31]

Fig. 8. Examples of tissue/cell-specific imaging applications of dynamic OCT. (a) Infiltrating breast cancer tissue^[87]; (b) esophageal tissue^[89]

Fig. 9. Techniques and results of OCT thermometry applied to thermophysical therapy monitoring. (a) RF ablation temperature field monitoring of an esophageal balloon catheter^[92]; (b) relationship between the speckle variance signal and temperature during laser treatment of skin lesion^[28]; (c) visualization of the depth of laser treatment using a noise-corrected speckle decorrelation algorithm^[91]