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Quantitatively assessing port-wine stains using a photoacoustic imaging method: A pilot study

Open AccessPublished:December 20, 2020DOI:https://doi.org/10.1016/j.jaad.2020.12.024
      To the Editor:
      Currently, the severity and treatment response in port-wine stains (PWSs) are assessed through clinic-based subjective or semiquantitative methods.
      • Sharif 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.
      • Wen L.
      • Zhang Y.
      • Zhang L.
      • et al.
      Application of different noninvasive diagnostic techniques used in HMME-PDT in the treatment of port wine stains.
      • Naran S.
      • Gilmore J.
      • Deleyiannis F.W.-B.
      The assessment of port wine stains in children following multiple pulsed-dye laser treatments.
      Photoacoustic imaging (PAI) is an emerging, hybrid, medical imaging technology.
      • Wang 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.
      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.
      Figure thumbnail gr1
      Fig 1Prospective study of the port-wine stain (PWS) levels of 4 patients showing the quantified PWS levels at 6 time points. From left to right: before treatment, immediately posttreatment, and 1, 2, 4, and 8 weeks posttreatment. The mean and the standard deviation are from the multiple measurements made on each patient at each time point. ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001. PDT, Photodynamic therapy.
      Figure thumbnail gr2
      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.
      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.

      Conflicts of interest

      None disclosed.

      References

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        • Taydas E.
        • Mazhar A.
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        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.
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        Application of different noninvasive diagnostic techniques used in HMME-PDT in the treatment of port wine stains.
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        • Wang X.
        • Pang Y.
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        Noninvasive laser-induced photoacoustic tomography for structural and functional in vivo imaging of the brain.
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