Spectral interferometric depth-resolved photoacoustic viscoelasticity imaging

Abstract

Viscoelasticity is closely related to the physiological characteristics of biological tissues. In this Letter, we propose a novel spectral interferometric depth-resolved photoacoustic viscoelasticity imaging (SID-PAVEI) method, to the best of our knowledge for the first time, which breaks the plight of surface viscoelasticity imaging and achieves an internal visible microscale SID-PAVEI in a noncontact fashion. In this work, we employ a high-sensitive and depth-resolved spectral domain low coherence interferometry (SDLCI) to remotely track photoacoustic-induced strain response of absorbers in situ. By decoupling the phase and amplitude of the photoacoustic-encoded spectral interference signal, the SID-PAVEI and scattering structure imaging (SSI) can be obtained simultaneously. Depth-resolved performance of the SID-PAVEI and the SSI in one scan were demonstrated by imaging biological tissues. The method opens new perspectives for three-dimensional microscale viscoelasticity imaging and provides a great potential in multi-parametric characterizing pathological information.

Photoacoustic micro‐viscoelastography for mapping mechanocellular properties

“…In addition, by implementing multiple channels using a microlens array and a linear array of ultrasonic transducers, the acquisition can be further accelerated dramatically [35]. Moreover, a cross-correlation processing algorithm between PA signal and reference signal without the lock-in amplifier device, the acquisition time can be reduced by nearly two orders of magnitude [36,37].…”

“…In future studies, depth-resolved and subsequent three-dimensional (3D) volumetric viscoelastic imaging may be recoverable by scanning layer by layer. In addition, the depth information also can be achieved without such time-consuming depth scanning, such as by exploiting optical coherence tomography (OCT) to detect depth-resolved PA response [23,36,38]. The advancements in the two aspects will enable high-throughput 3D micromechanical imaging.…”

Non-contact sub-nanometer displacement sensing based on optical digital coherent detection using frequency-domain filters

“…Differential operations in signal processing can result in noise doubling and additional degradation of 3 dB SNR [19,20]. Additionally, the loss of initial phase information in cross-correlation techniques makes it challenging to apply them to real-time detection [21,22]. To overcome these challenges, a novel displacement sensing method based on phase-diversity optical digital coherent detection [23][24][25] has recently been introduced [26][27][28].…”