Quantitative evaluation of severity in psoriatic lesions using three‐dimensional morphometry

Abstract

The severity of psoriasis has been traditionally assessed by measures, such as the psoriasis area and severity index (PASI), the psoriasis severity scores, and the lesional severity scores. As a result, even experienced dermatologists show variations when attempting to determine the severity of psoriasis. Therefore, a better non-invasive and objective measurement of clinical signs is needed. In this study, an instrument, a so-called 'stereoimage optical topometer' (SOT), based on a new concept of 'stereoimaging' was used to measure the three-dimensional skin surface. The aim of this study was to compare the results obtained by the SOT with the visual score of psoriasis lesion. Thirty psoriatic patients were enrolled in this study. Initially, the severity of the infiltration and the scale of 134 psoriatic lesions were assessed by using a visual scoring system (0: none, 1: mild, 2: moderate, 3: severe, and 4: very severe), as scored by five dermatologists. The SOT was then used to quantify the severity of each psoriatic lesion using four three-dimensional SOT parameters (Sa, SL, SA, and SV). Secondly, the involved skin-surface area in the psoriasis cases was scored by the naked eye by the five dermatologists and by image analysis. Statistically significant differences were observed between grades 0, 1, 2, and 3 in terms of the severity measurements of the individual psoriatic lesions by SOT when using the parameters Sa, SL, SA, and SV. Therefore, it was concluded that there is a strong correlation between the results measured by visual scoring and by SOT in psoriasis.

Computer-aided measurement of psoriatic lesion area in a multicenter clinical trial—Comparison to physician's estimations

“…Previous studies have indicated wide variations between observer's estimates of involved surface area [4][5][6][7][8]. Computeraided image analysis (CIA) was used by several authors to minimize the variability of psoriatic area estimation [6][7][8][9][10][11][12][13][14]. Both photographs and drawing were used in CIA.…”

“…Both photographs and drawing were used in CIA. The methods for measurement of the intensity of other psoriasis signs were also developed [9,11,14]. Curved body sites and consequently the uneven illumination of photographs (shadows) is the main obstacle for efficient CIA.…”

Semi‐quantitative assessment of the distribution of skin lesions in patients with psoriasis and psoriasis arthritis

“…There are many promising publication titles regarding photometric measurements of lesion thickness (21), blood flow (22) and other markers of psoriasis. However, these methods require complicated and expensive equipment and methodology and their application is tested on selected skin areas ranging in size from microscopic (23), flat surfaces of limbs (22) to flattened large body chunks (4). It is clear that these methods are still under development and lack the ability to automatically resolve lesions on the whole skin surface.…”

Objective interpretation of severity of SLS induced edema by stereoimaging

“…Disparity data contains information on height measured from not only from the original x and y coordinates but also of the z co-ordinate--the height. Thus, this 3D information can be easily calculated and used to study characteristic skin surface contours [15][16][17][18].…”