Investigation of optical attenuation imaging using optical coherence tomography for monitoring of scars undergoing fractional laser treatment

Abstract

We demonstrate the use of the near-infrared attenuation coefficient, measured using optical coherence tomography (OCT), in longitudinal assessment of hypertrophic burn scars undergoing fractional laser treatment. The measurement method incorporates blood vessel detection by speckle decorrelation and masking, and a robust regression estimator to produce 2D en face parametric images of the attenuation coefficient of the dermis. Through reliable co-location of the field of view across pre- and post-treatment imaging sessions, the study was able to quantify changes in the attenuation coefficient of the dermis over a period of ∼20 weeks in seven patients. Minimal variation was observed in the mean attenuation coefficient of normal skin and control (untreated) mature scars, as expected. However, a significant decrease (13 ± 5%, mean ± standard deviation) was observed in the treated mature scars, resulting in a greater distinction from normal skin in response to localized damage from the laser treatment. By contrast, we observed an increase in the mean attenuation coefficient of treated (31 ± 27%) and control (27 ± 20%) immature scars, with numerical values incrementally approaching normal skin as the healing progressed. This pilot study supports conducting a more extensive investigation of OCT attenuation imaging for quantitative longitudinal monitoring of scars. En face 2D OCT attenuation coefficient map of a treated immature scar derived from the pre-treatment (top) and the post-treatment (bottom) scans. (Vasculature (black) is masked out.) The scale bars are 0.5 mm.

Optical coherence tomography for the investigation of frontal fibrosing alopecia

“…A low AC in the cicatricial area might be explained by reduced water content of the atrophic cicatricial skin as AC decreases when water content decreases. Although AC is typically increased by collagen deposition, data on AC values in scars is derived from studies on hypertrophic (increased net collagen) and not atrophic (decreased net collagen) scars . Our results show that FFA scarring is not due to an increased amount of collagen but instead a replacement of healthy tissue by fibrosis.…”

“…This value provides valuable information on the composition of the medium . Inflammation and collagen increase the AC by absorbing and scattering light, respectively …”

In vivo volumetric quantitative micro-elastography of human skin

“…An important next step is to perform pilot clinical studies to determine if this method has the required sensitivity to distinguish regions of pathological tissue. One attractive application of this method is the evaluation of the stiffness of burn scars, further extending our OCT-based approaches to quantify the structure and microvasculature of burn scars [31,41,42]. An exciting future possibility is the combination of these methods to perform a more comprehensive characterization of the micro-scale physical properties of skin than has been performed to date.…”

Parametric imaging of attenuation by optical coherence tomography: review of models, methods, and clinical translation

“…Es'haghian et al 69 further extended vasculature-masked OCT attenuation imaging to longitudinal monitoring of hypertrophic scars undergoing fractional laser ablation treatment, as shown in Figs. 6(d) and 6(e).…”