Quantitatively assessing port-wine stains using a photoacoustic imaging method: A pilot study
Authors: Haonan Zhang, Guolong Zhang, Yunfeng Zhang, Long Wen, Mengjiao Zhang, Jing Pan, Peiru Wang, Xueding Wang, Qian Cheng, Xiuli Wang
Journal: Journal of the American Academy of Dermatology (2021)

Currently, the severity and treatment response in port-wine stains (PWSs) are assessed through clinic-based subjective or semiquantitative methods.1Sharif S.A. Taydas E. Mazhar A. et al.Noninvasive clinical assessment of port-wine stain birthmarks using current and future optical imaging technology: a review: noninvasive clinical assessment of port-wine stain birthmarks.Br J Dermatol. 2012; 167: 1215-1223Crossref PubMed Scopus (32) Google Scholar, 2Wen L. Zhang Y. Zhang L. et al.Application of different noninvasive diagnostic techniques used in HMME-PDT in the treatment of port wine stains.Photodiagnosis Photodyn Ther. 2019; 25: 369-375Crossref PubMed Scopus (12) Google Scholar, 3Naran S. Gilmore J. Deleyiannis F.W.-B. The assessment of port wine stains in children following multiple pulsed-dye laser treatments.Ann Plast Surg. 2008; 60: 426-430Crossref PubMed Scopus (7) Google Scholar, 4Humbert P. Fanian F. Maibach H.I. Agache P. Agache's Measuring the Skin: Non-Invasive Investigations, Physiology, Normal Constants. Springer International Publishing, 2017Crossref Scopus (1) Google Scholar Photoacoustic imaging (PAI) is an emerging, hybrid, medical imaging technology.5Wang X. Pang Y. Ku G. Xie X. Stoica G. Wang L.V. Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain.Nat Biotechnol. 2003; 21: 803-806Crossref PubMed Scopus (1497) Google Scholar It uses the intrinsically strong optical absorption by hemoglobin in the visible and near-infrared spectral region to quantify the blood perfusion under the skin. We adapted a commercial, portable, light emitting diode–based PAI system for the clinical assessment of PWSs. A new imaging parameter, the "PWS level," indicating the severity of PWS lesions, can quantitatively assess the severity and treatment response in PWS lesions. Thirty-five patients with a facial PWS were included for the PWS level validation. Because of financial reasons, only 4 of these patients were enrolled in a 6-checkpoint prospective study over a 2-month treatment cycle of hematoporphyrin monomethyl ether photodynamic therapy. To observe PWS level changes, they were imaged immediately after treatment and at 1, 2, 4, and 8 weeks posttreatment. With 1 additional patient imaged at 2 time points (before treatment and at 8 weeks posttreatment), 5 patients were also enrolled in the longitudinal 2-checkpoint efficacy assessment study. Details regarding the PWS level, PAI schematic, protocol, patient demography, clearance score standards, and results of the PWS level validation and longitudinal 2-checkpoint treatment efficacy evaluation of 5 patients can be found in the Supplemental Material available via Mendeley at https://data.mendeley.com/datasets/rzsjvj9m2r/1. The trend in the PWS levels was similar in all 4 patients enrolled in the 6-checkpoint study (Fig 1). Immediately posttreatment, a quick decrease in the PWS level occurred because of a swelling effect. Local blood perfusion is reduced because of vascular endothelial destruction after PDT. At 1 week posttreatment, the levels rose because of short-term inflammation. However, at 2, 4, and 8 weeks, they dropped again and were lower than the pretreatment measurements, reflecting the long-term outcomes. Significant differences were achieved in unpaired t tests comparing the posttreatment (immediately and at 8 weeks) and pretreatment levels per patient. Corresponding clinical pictures are shown in Fig 2.Fig 2Clinical pictures taken at the 6 time points during the 2-month follow-up from the 4 patients involved in the prospective study. PDT, Photodynamic therapy.View Large Image Figure ViewerDownload Hi-res image Download (PPT) The treatment response was also evaluated in the 2-checkpoint longitudinal study (Supplemental Fig 1). The mean PWS levels before treatment and at 8 weeks posttreatment were 2.45 ± 0.23 and 1.73 ± 0.14, respectively (P < .01). The PWS level reduction at 8 weeks posttreatment per patient was computed and compared with the clearance scores allocated by 5 dermatologists. The standard deviation of each PWS level reduction was smaller than that of the corresponding clearance score, suggesting a better repeatability in assessing response to treatment. In addition, the average PWS level reduction of this cohort was 49.30% ± 9.50%, demonstrating a satisfactory treatment effect. The findings indicate a new quantitative assessment method for PWS severity and treatment response, which shows better repeatability compared with semiquantitative visual assessment. In conclusion, we propose a new alternative to evaluate PWS, which is now being developed into a practical option in the clinic for monitoring purposes. None disclosed.