A clinimetric assessment of the validity and reliability of 3D technology for scar surface area measurement.

INTRODUCTION: The quality of scars has become an important outcome of burn care. Objective scar assessment through scar surface area measurement enables quantification of scar formation and evaluation of treatment efficacy. 3D technology has proven valid and reliable but often remains cumbersome, expensive, and time-consuming. 3D technology with depth sensors on mobile devices has become available and might surpass these limitations. This study provides a clinimetric assessment of the validity and reliability of a 3D system with a depth sensor for scar surface area measurement. METHODS: A technology involving a depth sensor mounted on a mobile device was used. Images and analyses were made with a custom-made software application. A standardized one-keyframe image capturing procedure was followed. To assess validity, stickers with predefined dimensions (8.01 cm2 - 77.70 cm2) were imaged in a single observer setting on various body parts of healthy volunteers. To assess reliability, hypertrophic scars, keloids, and normotrophic scars were imaged and rated by two observers independently. Data are expressed as mean (+/-SD), Coefficient of Variation (CV), Intraclass Correlation Coefficients (ICC), and Limits of Agreements (LoA). RESULTS: Eighty stickers placed on 20 healthy volunteers showed validity with CV between 0.62%- 1.67% for observer A and 0.75%- 1.19% for observer B. For the reliability study, 69 scars on 36 patients were included. Mean scar surface area ranged from 0.83 cm2 to 155.59 cm2. Mean scar surface area measurement was 13.83 cm2 (SD 23.06) for observer A and 13.59 cm2 (SD 23.31) for observer B. Adjusted interobserver CV for trained observers is estimated as 5.59%, with corresponding LoA = 0 ± 0.15 x mean surface area. Interobserver ICCs were 0.99-1.00. CONCLUSION: This 3D technology with a depth sensor for measuring scar surface area provides valid and reliable data and thereby surpasses expensive and time-consuming 3D cameras.

High-resolution ultrasound for keloids and hypertrophic scar assessment.

Most of the widely used scales to evaluate scars are subjective relying on clinical observations. There is a growing need to find out a noninvasive objective tool for this purpose. The study is aimed at evaluating the value of the high-resolution ultrasound in the assessment of the scars when compared with a clinical evaluation scoring system, the Vancouver Scar Scale (VSS). The study included 22 patients with hypertrophic scars or keloids. At baseline, scars were assessed using the Vancouver Scar Scale and high-resolution ultrasound (13-MHz probe). Patients received three Nd:YAG laser sessions (100 J/cm2 fluence, pulse width 50 ms, frequency rate 2 Hz, and spot size 7 mm) at 1-month intervals. Pulses were applied in a painting motion till reaching the clinical end point which is mild erythema. After the 3rd session, lesions were evaluated again using the VSS and the high-resolution ultrasound. The Vancouver Scar Scale decreased significantly after treatment in both treatment groups. Radiological evaluations showed significant improvement in lesion thickness and echogenicity, but not the lesion vascularity. There was a significant difference between the improvement percent measured by the VSS and high-resolution ultrasound (p = 0.001). The percent of HTS improvement was higher than that of keloid improvement. Among all the studied variables, it seems that female sex is the only factor which predicts better treatment outcome. The combined clinical and radiological assessment of scars is helpful in assessing these lesions and comparing the efficacy of different treatment modalities.

Evaluating accuracy and reliability of active stereophotogrammetry using MAVIS III Wound Camera for three-dimensional assessment of hypertrophic scars.

OBJECTIVE: Current strategies for estimating positive scar volume following burns is limited to employing subjective scar scales. This study assesses the accuracy and reliability of Measurement of Area and Volume Instrument System (MAVIS) III, a portable 3D active stereophotogrammetric imaging system, for non-invasive assessment of hypertrophic scar volume and elucidates factors that leads to inaccurate volume determination. METHODS: To determine accuracy, hypertrophic scars arising in various skin and wound types were modeled using moldable putty substance. Volumetric measurements calculated by the camera's software were compared to measurements determined by fluid displacement. To assess inter-rater reliability, 25 images of patients with hypertrophic scars on various anatomical regions (hand, arm, leg, and flank area) were assessed by three blind evaluators. RESULTS: Volumetric measurements obtained from MAVIS III ranged from adequate to excellent accuracy (Pearson's correlation coefficient of 0.54-0.90) compared to measurements determined by fluid displacement. The reliability of volume determination of human hypertrophic scars was rated excellent (overall Intraclass correlation coefficient of 0.95). CONCLUSIONS: This study finds that MAVIS III is accurate in its volumetric measurements and is reliable between users; making it a potential candidate for non-invasive assessment of hypertrophic scars. Further considerations for refining active stereo-photogrammetry and the user interface of the software are also highlighted to allow superior evaluation of scar volume.

Comparison between high-frequency ultrasonography and histological assessment reveals weak correlation for measurements of scar tissue thickness.

OBJECTIVE: Current methods for evaluating scar tissue volume following burns have shortcomings. The Vancouver Burn Scar scale is subjective, leading to a high variability in assessment. Although histological assessment via punch biopsy can discriminate between the different layers of skin, such an approach is invasive, inefficient, and detrimental to patient experience and wound healing. This study investigates the accuracy of high-frequency ultrasonography, a non-invasive alternative to histology, for measuring dermal and epidermal thickness in scar tissue. METHODS: Scar thicknesses of 10 patients following burns were assessed using a 2-D high-frequency ultrasound probe. The scars were then biopsied using a circular 4mm punch biopsy for histological assessment. Dermal, epidermal, and total thickness of the scar tissue was measured using ultrasound and histology, and correlations between the two measurements were calculated. RESULTS: There was not a strong correlation between ultrasound measurement and histological analysis for epidermal, dermal, and total thickness (Spearman's rank correlation of -0.1223, -0.6242, and -0.6242) of scar tissue. CONCLUSIONS: Measurements of scar thickness using high-frequency ultrasonography did not recapitulate the in vivo dermal, epidermal and total thickness. Based on these findings, strategies for further optimization of 2-D ultrasonography is discussed before clinical and research use.

Ultrasound assessment of scald scars in Asian children receiving pressure garment therapy.

BACKGROUND/PURPOSE: Scar formation after scald injury in children is managed commonly by application of pressure garment. The duration of the treatment depends on clinical assessment. The objective of the study was to evaluate the efficacy of the pressure garment therapy and to correlate the clinical assessment scar thickness with ultrasound measurement. METHODS: Prospective study of children with hypertrophic scars receiving pressure garment therapy was carried out between 1993 and 1998. The scars were mapped with paper cutting. Representative scar sites were scored clinically according to Vancouver General Hospital Burn Assessment Scale (pigmentation, vascularity, pliability, height, pain, itchiness). Blind to the clinical results, 2 radiologists measured the scar thickness of the same sites with ultrasonography (5 to 10 MHz transducer, General Electric LOGIQ 500). The correlation between the clinical scores and ultrasound measurement of scar thickness were analysed using analysis of variance (ANOVA). RESULTS: The median age of 58 children with scald injury (M:F = 36:22) was 2.8 years (0.5 to 15.8 years). The mean percentage of scald was 8.8% (24% had scald area >10%). In addition, there were 5 children with burn from naked flame and 9 children with keloid secondary to surgical incisions. With pressure garment therapy, the scar thickness reached a plateau 1 (1/2) years after the injury and began to decline gradually thereafter. The clinical estimation of scar thickness correlated well with the ultrasound measurement (ANOVA, P =.003, Adjusted R square = 0.99). The accuracy rate of clinical thickness estimation was 67%. Overestimation and underestimation accounted for 15% and 18%, respectively. There also was good correlation between total clinical score and the ultrasound measurement (ANOVA, P <.001). CONCLUSIONS: In children with scald injury, the pressure garment needs to be continued for a minimum of 1 year. Ultrasound measurement correlates well with overall score of the Vancouver General Hospital Burn Assessment Scale but not individual components of the scoring system except wound height.

The cutometer and ultrasonography in the assessment of postburn hypertrophic scar--a preliminary study.

Sixteen patients with various degrees of postburn hypertrophic scars were evaluated by ultrasonography and elastometry. An Aloka Echo Camera (SSD-500) with a 7.5 MHz probe and a Cutometer SEM 575 skin elastometer were used. Serial monthly examinations were performed using both pieces of equipment. In some patients, more than one scar was assessed. The assessments were correlated with clinical grading of the progress of the scars. It was noted that ultrasonography was very sensitive in the localization of scar tissues, distinguishing them from normal skin, assessment of thickness and also delineation of the extent of scar tissues. The subcutaneous part of the scar could be assessed. Cutometer SEM 575 is a new machine that applies a gentle suction to the skin to measure its viscoelasticity. It is sensitive, the inter-observer variation is low, and it could be used for the grading of a scar. These two assessment techniques compliment other methods of scar assessment and will prove useful when assessment of response to treatment is required.