Laser treatment of port wine stains: therapeutic outcome in relation to morphological parameters

Abstract

Thirty patients were treated with a flashlamp-pumped pulsed dye laser, with 0.45 ms pulse width and 585 nm wavelength. Punch biopsies were taken prior to treatment, and the biopsies were examined morphometrically. Three different test sites were exposed to laser light of fluence 5.25, 6.50 and 7.75 J/cm2. The degree of blanching was examined 6-8 weeks after treatment, and each site was retreated four times. Six patients (20%) achieved poor blanching, eight patients (27%) obtained moderate lightening and 16 patients (53%) showed good response. The vessels of the good responders were located significantly more superficially than the vessels of the moderate and poor responders (P < 0.05). The poor responders had significantly smaller vessels than the moderate and good responders (P < 0.01). The moderate responders had deeper, but larger vessels, than the poor responders. Hence, an increasing vessel diameter reduces the negative outcome of increasing vessel depth. The vessel diameter was correlated to the colour (P < 0.01), e.g. the mean vessel diameter was increasing from 16.5 microns in pink lesions to 51.2 microns in purple lesions. The vessel depth was partly reflected in the lesional colour, as the pink and purple lesions had significantly deeper vessels than the red ones (P = 0.02). These results indicate that pink lesions predict poor blanching due to deeply located small vessels, while red lesions predict a good therapeutic result because of more superficially located vessels.

A new Monte Carlo program for simulating light transport through Port Wine Stain skin

“…This is in agreement with previous biopsy [3,4] and simulation [26,40] studies. As a result, any combination of these three vessel parameters, for a fixed epidermis, creates a unique spectral reflectance curve.…”

“…However, the blood vessel parameters predicted by the procedure were shown to be consistent with those found elsewhere in the literature [3,4] and resulted in spectral reflectance curves, which reproduced measured spectra to a satisfactory degree of accuracy. It is likely that further iterations of the procedure would have resulted in a closer fit between measured and simulated spectra, as well as improved repeatability in the predicted vessel parameters.…”

“…Biopsy studies [3,4] have shown that skin colour is affected by the depths, diameters and number density of PWS vessels. Although, skin colour measurements are the most established and widely used technique for the objective assessment of PWS skin [5][6][7], to date this method has not been used to extract such information.…”

Thermal depth profiling of vascular lesions: automated regularization of reconstruction algorithms

“…As a basis for 'realistic' PWS geometries, we chose to use data published by Fiskerstrand et al (1996) in which histological data of 32 PWS patients were stratified by response to laser treatment. The resulting data for each response group were presented as distributions of vessel diameter and depth.…”

“…A simplification in our approach is that we assumed all vessels to be horizontally positioned and parallel to each other. Using the vessel diameter and depth distributions published by Fiskerstrand et al (1996) as a basis, we randomly resampled five geometries for each of the following response groups to laser treatment. Three resampled geometries are illustrated in figures 1(A), (D) and (G) for 'poor', 'moderate' and 'good' responders, respectively.…”