Quantification of skin lesions using high-frequency ultrasound and shear wave elastography in port-wine stain patients: a clinical study

Abstract

Background: This study aimed to assess the different types of port-wine stain (PWS) skin lesions quantitatively using high-frequency ultrasound (US) and shear wave elastography (SWE) before and after treatment, and investigate the feasibility and application value of high-frequency US and SWE in PWSs.

Methods: A total of 195 PWS patients with 238 skin lesions before treatment and 72 follow-up PWS patients with 90 skin lesions were assessed using high-frequency US and SWE. The skin lesions were divided into four groups: pink-type, purple-type, thickened-type, and nodular-type PWSs. Gray-scale US was used to observe normal skin, observe the skin changes of lesions, and assess the skin thickness. The thickened skin was calculated. Power Doppler (PD) signal grades were used to assess the skin blood signals. SW velocity (in m/s) and Young's elastic modulus (in kPa) were used to assess the stiffness of normal skin and skin lesions. The heightened SWE was also calculated.

Results: The dermis hypoechogenicity, thickness of thickened skin, and skin PD signal grades were significantly higher in all PWS-type groups compared with the normal-skin group (all P<0.05). The thickened skin and skin PD signal grades in the nodular-type and thickened-type group were significantly thicker and higher than those in the pink-type and purple-type group (all P<0.05). The PD signal grades in the purple-type was significantly higher than that in the pink-type group (P<0.05). All SWE values of PWS lesions were significantly higher in the transverse section than those in the longitudinal section (all P<0.05). The differences in heightened Emean, Emin, Cmean, and Cmin between each PWS group and the normal-skin group were not significant. The heightened Emax and Cmax in the nodular-type PWS group was significantly higher than those in the normal-skin group and pink-type, and purple-type PWS groups (all P<0.05). The heightened Emax and Cmax were significantly higher in the thickened-type PWS group than those in the normal-skin group (all P<0.05). In the evaluation of therapeutic effects, the ratio of dermis hypoechogenicity in pink-type lesions significantly decreased, and thickened skins in all groups were significantly thinned (all P<0.05). The differences of PD signal grades, heightened Emax, and Cmax in all groups between pre-treatment and post-treatment showed no significance.

Conclusions: High-frequency US and SWE show feasibility and application values assessing PWS skin lesions. Their features include dermis hypoechogenicity, thicker skin, higher PD signal grades, higher Emax, and higher Cmax. Thicker skin is thus the best feature for assessing therapeutic effect.

Keywords: High-frequency ultrasound (high-frequency US); port-wine stain (PWS); shear wave elastography (SWE); treatment.

Conflict of interest statement

Conflicts of Interest: The authors have no conflicts of interest to declare.

2019 Annals of Translational Medicine. All rights reserved.

Figures

Figure 1

Gray-scale US used to assess the skin thickness (red line) of PWS lesions on the left face (A) and the normal side on the right face (B). PWS, port-wine stain; US, ultrasound.

Figure 2

Blood signals of PWS lesions assessed using PD ultrasound. (A) Grade 0 of a pink-type lesion; (B) grade 1 of a thickened-type lesion; (C) grade 2 of a thickened-type lesion; (D) grade 3 of a nodular-type lesion. PD, power Doppler.

Figure 3

SWE used to assess the skin stiffness of PWS lesions on the right temple (A) and the normal side on the left temple (B). PWS, port-wine stain; SWE, shear wave elastography.

Figure 4

Box-and-whisker plots of Emean, Emin, Emax, Cmean, Cmin, and Cmax of PWS lesions in transverse and longitudinal sections. The top and bottom of each box represent the 75th percentile and 25th percentile, respectively; the horizontal line in each box represents the median; and the top and bottom of the whiskers represent the minimum and maximum, respectively. *, P<0.05. Cmax, maximum velocity; Cmean, mean velocity; Cmin, minimum velocity; Emax, maximum elastic modulus; Emean, mean elastic modulus; Emin, minimum elastic modulus; L, longitudinal section; PWS, port-wine stain; T, transverse section.