Alternative Contrast Mechanism in Optical Coherence Tomography: Temporal Speckle Synchronization Effects

Abstract

We propose an alternative optical coherence tomography (OCT) contrast mechanism based on analysis of speckle temporal synchronization using B-mode OCT structural images. We show that the changes in synchronized speckle intensities with time may be used to distinguish between different tissue types, thus providing a novel and potentially useful contrast for OCT imaging. The developed methodology is tested in scattering flow phantoms, and in vivo on cervical cancer tumour grown within a mouse dorsal skin window chamber model. Derived speckle synchronization metric is compared with autocorrelation function analysis to demonstrate its different nature. The phantom and pre-clinical in vivo results suggest that the proposed synchronization approach is sensitive to tissue type/pathology, potentially enabling tumour quantitative evaluation and its delineation from surrounding normal tissues.

Analysis of low-scattering regions in optical coherence tomography: applications to neurography and lymphangiography

“…It is important to note here, that although the number of 1080 pixels per ROI was considered to be sufficient to detect structures of interest, these 1080 statistical samples of the speckle distribution per small analysis volume may not be fully independent at OCT's frame rate of 40 Hz and the resultant inter-frame temporal spacing of 25 ms. In our earlier in-vivo experiments [42,43] we explored the range of OCT signal decorrelation times for blood, tumor and normal tissues. For blood, decorrelation times were found to range from ∼20 ms (0.5 mm/s flow rate in small vessels like capillaries) to ∼1 ms (>12 mm/s flow rate in larger vessels); tumor and normal tissues had much longer decorrelation times reaching ∼500 ms and 1.1s (skin), respectively.…”