Correlation-stability approach in optical microelastography of tissues

摘要

In the conventional cross-correlation approach to reconstruction of displacements (and then the strain field), the reduction of correlation between the consequently obtained images caused by distortions of scatterer patterns in deformed tissues is a negative factor reducing the accuracy of the displacement-field reconstruction. However, just this reduction in the cross-correlation between the images of deformed tissues can be intentionally used for evaluation of the tissue rigidity. Evidently, in areas with higher rigidity the distortions of the scatterer pattern in deformed tissues are smaller and, correspondingly, the reduction in the cross-correlation between the consequent OCT images is also smaller. Observation of such a cross-correlation field we call the correlation-stability approach (CS-approach) to mapping the relative rigidity of biological tissues. The proposed CS-approach is illustrated by numerical simulations corresponding to two characteristic cases (sheared or compressed samples with average strain range 25-100 %). This strain level is favorable for performing such mapping "by hand" and in vivo conditions. Some examples of such in vivo obtained relative-rigidity images are presented in this report.