A correlation-stability approach to elasticity mapping in optical coherence tomography

A variant of compressional optical coherence elastography for mapping of the relative stiffness of biological tissues is reported. Unlike conventionally discussed displacement-based (DB) elastography, in which the decrease in the cross-correlation between subsequently obtained images is a negative factor causing errors in the mapping displacement and strain fields, we propose to intentionally use the difference in the correlation stability (CS) for deformed-tissue regions with different stiffnesses. We compare the parameter ranges (in terms of noise-to-signal ratio and strain) in which the conventional DB and CS approaches are operable. It is shown that the CS approach has advantages such as a significantly wider operability region in terms of strain and is more tolerant to noise. This is favorable for freehand implementation of the CS approach. Examples of simulated and real CS-based elastographic optical coherence tomography images are given.