Body surface area measurement and soft clustering for PASI area assessment

Shear wave elastography and microvascular ultrasound in response evaluation to calcipotriol+betamethasone foam in plaque psoriasis

Psoriasis (PsO) is a chronic skin disease. This study aims to evaluate clinical and subclinical response to calcipotriol+betamethasone foam, in patients with PsO, comparing, for the first time, data from microvascular ultrasound (MicroV) and shear wave elastography (SWE) with Psoriasis Area and Severity Index (PASI).

METHODS

Between November 2018 and April 2019 in Tor Vergata Hospital (Roma, Italy), we enrolled 26 patients with PsO who were ageds 20-75 years, with PASI score ≥4, candidated for calcipotriol+betamethasone foam treatment. They underwent MicroV and SWE evaluation at baseline (T₀) and after 4 weeks of treatment (T₄). Clinical follow-up was carried on at T₄, T₈ and T₁₂. Student's t-test (p values<0.05 statistically significant) was used to compare SWE and PASI values.

RESULTS

At T₀, SWE stiffness values of target plaques (61.5% on elbows, 23% knees, 7.7% sacrum,7.7% legs) were significantly higher than values under healthy skin. At T₄, all patients showed a significant reduction of PASI; MicroV showed reduction in vascularisation of responsive plaques in 85% of cases, only in 15%, the vascularisation degree remained stable; and SWE values of target plaques were significantly lower compared with T₀. Only in 7.7%, there was a relapse at T₁₂.

CONCLUSIONS

Calcipotriol+betamethasone foam is a very effective topical treatment in a short-medium term follow-up in patients with PsO. MicroV and SWE evaluate response to treatment (in term of plaque vascularisation and stiffness), so they could represent promising early indicators of therapeutic response and help the physician to establish a better clinical-therapeutic management of patients with PsO.

3D surface roughness measurement for scaliness scoring of psoriasis lesions

Psoriasis is an incurable skin disorder affecting 2-3% of the world population. The scaliness of psoriasis is a key assessment parameter of the Psoriasis Area and Severity Index (PASI). Dermatologists typically use visual and tactile senses in PASI scaliness assessment. However, the assessment can be subjective resulting in inter- and intra-rater variability in the scores. This paper proposes an assessment method that incorporates 3D surface roughness with standard clustering techniques to objectively determine the PASI scaliness score for psoriasis lesions. A surface roughness algorithm using structured light projection has been applied to 1999 3D psoriasis lesion surfaces. The algorithm has been validated with an accuracy of 94.12%. Clustering algorithms were used to classify the surface roughness measured using the proposed assessment method for PASI scaliness scoring. The reliability of the developed PASI scaliness algorithm was high with kappa coefficients>0.84 (almost perfect agreement).