Purpose or Case Report: Acoustic radiation force imaging (ARFI) is a type of quantitative sonoelastography (SE) that has been used to determine tissue stiffness in many disorders including liver fibrosis, breast cancer, thyroid nodules and more recently, cutaneous scleroderma. However the use of this technology for the assessment of skin lesions in the paediatric population has not yet been investigated. The purpose of this study is to test the feasibility of using ARFI SE to quantify the stiffness of morphea or localized scleroderma (LS) and hypertrophic burn scars (HTS), two skin conditions in which there is excessive deposition of collagenous and non-collagenous extracellular matrix causing fibrosis.
Methods & Materials: We employed conventional ultrasound (US) and ARFI SE to characterize changes in the skin of pre-assigned LS and HTS lesions and compared them to the normal contralateral sites as controls. The inclusion criteria was clinical diagnosis of the corresponding skin condition by a specialist. For each participant, a “target lesion” was selected and marked by the clinician as well as a section of contralateral matched normal skin for US and ARFI measurements. The Wilcoxon signed-rank test was used to compare scar and control sites.
Results: 26 patients from the outpatient Morphea (n = 13) and Burn (n = 13) clinics at our tertiary pediatric hospital were prospectively recruited (age range: 4 to 16; 12 females, 14 males). Lesions varied in location and severity. As expected LS lesions and HTS were significantly stiffer than normal skin (E means of 17.61 for LS and 41.11 kPa for HTS respectively, versus 10.32 and 10.05 kPa for the normal controls).
Skin thickness of the LS lesions was 30.7% thinner than the respective healthy skin, but the difference between means was only significant for the dermal layer. HTS were significantly thicker than the control sites (p < 0.05). Mean thickness values for the scar and control sites were 4.06 mm and 1.43 mm respectively. Variable changes in echogenicity and vascularity were seen in both group of lesions.
Conclusions: This study demonstrated the feasibility of using ARFI SE to discriminate between normal skin and fibrosclerotic skin conditions (LS and HTS) by measuring skin stiffness. In addition, the findings show that both these types of lesions are significantly stiffer than normal skin. Future research should focus on establishing reference data and determining the technology’s ability to detect scar changes over time and evaluate response to treatment.