Table 1.

Comparison of DPIV and Scanning DLS-OCT. A comparison of the benefits and limitations of each technique is shown. Sample values as demonstrated in our experiments are given, although these values do not necessarily reflect the theoretical limits of the techniques. ROI = region of intersest. SNR = signal-to-noise ratio. CSF = cerebrospinal fluid.

	DPIV	Scanning DLS-OCT
Scattering Regime	Optimized for sparsely scattering media (<1 particle / focal volume), but possible to be used in speckled regime	Optimized for densely scattering media (≫1 particle / focal volume)
Speed of Flow	Slow (<100 μm/s) or faster flow possible, but SNR decreased by fast out-of-plane flow (Trachea 20–50 μm/s, CSF 20–100 μm/s, Epithelium 100–1000 μm/s)	Optimized for faster flows (Epithelium 100–1000 μm/s)
Assumption of Stationarity	Spatial stationarity in xz plane over ROI (CSF 20×20 μm2, Trachea 50×50 μm2, Epithelium 120×120 μm2), temporal stationarity over the aquisition of two separate velocity measurements at a single location (15 – 50 s acquisition time)	Temporal stationarity for duration of scanning at a single point (6 –10 s) or entire sample (60 – 90 s), spatial stationarity over lateral extent of scan (30 – 50 μm)
Temporal Resolution	Dictated by interframe time for 2D2C ∼50 ms, or by duration of total acquisition in 3D3C (15 – 50 s)	Dictated by temporal duration of scan for 1D3C (6 – 10 s), or entire acquisition time for 3D3C (60 – 90 s)
Spatial Resolution	Axial and lateral spatial resolution dictated by ROI in processing (20×20 μm2 − 120×120 μm2)	Axial spatial resolution equivalent to imaging system (∼7 μm), lateral resolution limited by extent of lateral scanning (30–50 μm)