Full-field swept-source optical coherence elastography

Optical coherence elastography (OCE) enables label-free imaging of tissue mechanical properties, but conventional scanning implementations have limited volumetric acquisition speed. We present a full-field swept-source optical coherence elastography (FF-SS-OCE) system, based on compressive loading, that provides rapid volumetric imaging of strain at a rate of 2 volumes/s, enabled by an effective OCT A-scan rate of 4.2 MHz, corresponding to an order-of-magnitude increase in imaging speed over previous OCE demonstrations. The system achieves a shot-noise-limited phase sensitivity in volumetric imaging by combining highly parallel signal detection using a full-field configuration, implementation of a common-path interferometer to minimize the impact of environmental noise, a highly stable tunable laser, and active reduction of spatial coherence to reduce cross-talk noise. We demonstrate, for the same signal-to-noise ratio (SNR) of ∼20dB, that FF-SS-OCE provides 41% higher phase sensitivity and 35% higher strain sensitivity compared to a scanning OCT system. We validate the method using structured phantoms and freshly excised human breast tissue, demonstrating rapid visualization of mechanical contrast and showing its potential to discern between tumor and healthy tissue based on their distinct mechanical properties. These results establish FF-SS-OCE as a promising approach for high-speed, high-sensitivity volumetric elastography in biomedical tissue imaging.