Computational multi-directional optical coherence tomography for visualizing the microstructural directionality of the tissue

Abstract

We demonstrate computational multi-directional optical coherence tomography (OCT) to assess the directional property of tissue microstructure. This method is the combination of phase-sensitive volumetric OCT imaging and post-signal processing. The latter comprises of two steps. The first step is an intensity-directional analysis, which determines the dominant en face fiber orientations. The second step is the phase-directional imaging, which reveals the sub-resolution depth-orientation of the microstructure. The feasibility of the method was tested by assessing muscle and tendon samples. Stripe patterns with several sizes were visualized in the phase-directional images. In order to interpret these images, the muscle and tendon structures were numerically modeled, and the phase-directional images were generated from the numerical model. The similarity of the experimental and numerical results suggested that the stripe patterns correspond to the muscle fiber bundle and its crimping.

Anisotropic properties of acoustically induced electric polarization in soft fibrous biological tissues

“…The presence of muscle fiber crimps and a complex extracellular matrix may result in smaller anisotropy of polarization. In the angular distribution of structural orientation in optical coherence tomography, 37) it has been reported that the peak representing the degree of orientation is broader in chicken breast muscle than in Achilles tendon.…”

A theoretical model for en face optical coherence tomography imaging and its application to volumetric differential contrast imaging

“…For the experimental validation of VDC imaging, we used a fiber-based spectral-domain OCT system [13]. The light source was a superluminescent diode (SLD, Superlum, Ireland) with a center wavelength and bandwidth of 840 nm and 100 nm, respectively.…”

“…Oida et al demonstrated computational multi-directional (CMD)-OCT for qualitatively visualizing the microscopic phase structure of the sample [13]. This method exploits the phase angle of 𝑠(𝒙 + Δ𝒙/2)𝑠 * (𝒙 − Δ𝒙/2), and hence is similar to our VDC method.…”

“…An example is artifacts found in A-scan-wise Doppler OCT images caused by the structure of superior tissue. Another example relates to the specific imaging condition required for computational multi-directional OCT [13]. In experiments, it was found that defocus is mandatory to achieve this method [14], but this necessity has not been explained in theory.…”

Theoretical model for en face optical coherence tomography imaging and its application to volumetric differential contrast imaging

“…An example is artifacts found in A-scan-wise Doppler OCT images caused by the structure of superior tissue. Another example relates to the specific imaging condition required for point-scanning computational multi-directional OCT [ 14 ]. In experiments, it was found that defocus is mandatory to achieve this method [ 15 ], but this necessity has not been explained in theory.…”