Microcirculatory changes identified by photoacoustic microscopy in patients with complex regional pain syndrome type I after stellate ganglion blocks

Abstract

Abstract. Complex regional pain syndrome (CRPS) is a chronic pain syndrome that causes intractable pain, disability, and poor quality of life for patients. The etiology and pathophysiology of CRPS are still poorly understood. Due to a lack of proper diagnostic tools, the prognosis of CRPS is primarily based on clinical observation. The objective of this work is to evaluate a new imaging modality, photoacoustic microscopy (PAM), for assisting diagnoses and monitoring the progress and treatment outcome of CRPS. Blood vasculature and oxygen saturation (sO 2 ) were imaged by PAM from eight adult patients with CRPS-1. Patients' hands and cuticles were imaged both before and after stellate ganglion block (SGB) for comparison. For all patients, both vascular structure and sO 2 could be assessed by PAM. In addition, more vessels and stronger signals were observed after SGB. The results show that PAM can help diagnose and monitor CRPS.

Multiscale Functional and Molecular Photoacoustic Tomography

“…For example, by using a 50 MHz focused ultrasonic transducer, the first AR-PAM achieved a lateral resolution of ~45 μm, an axial resolution of ~15 μm and an imaging depth of ~3 mm in tissue [8, 40]. Such an imaging depth is sufficient for melanoma staging [40] and pain treatment evaluation [41] in the human skin. By using a similar design but with a 5 MHz transducer, photoacoustic macroscopy (PAMac) increased the imaging depth to ~38 mm, with a relaxed lateral resolution of ~500 μm and axial resolution of ~144 μm [42, 43].…”

In vivophotoacoustic microscopy of human cuticle microvasculature with single-cell resolution

“…[37][38][39][40][41][42][43] Combined with the flow speed imaging techniques reported previously, [44][45][46] OR-PAM has been demonstrated as a powerful tool to acquire such important parameters of the microcirculation as sO 2 , DsO 2 , C Hb , v Hb , and the metabolic rate of oxygen in tissues. [37][38][39][40][41][42][43] Combined with the flow speed imaging techniques reported previously, [44][45][46] OR-PAM has been demonstrated as a powerful tool to acquire such important parameters of the microcirculation as sO 2 , DsO 2 , C Hb , v Hb , and the metabolic rate of oxygen in tissues.…”

Detecting both melanoma depth and volume in vivo with a handheld photoacoustic probe

“…[8][9][10][11] In PAT, the target is first illuminated with a short laser pulse. Then the laser light is absorbed by the target, leading to a temperature rise and a subsequent initial pressure rise.…”