Imaging techniques in the diagnosis and monitoring of psoriasis

Structural and functional imaging of psoriasis for severity assessment and quantitative monitoring of treatment response using high-resolution optoacoustic imaging

Psoriasis is a chronic inflammatory skin disease, characterized by thick scaly plaques. It imposes a notable disease burden with varying levels of severity affecting the quality of life significantly. Current disease severity assessment relies on semi-objective visual inspection based on the Psoriasis Area and Severity index (PASI) score that might not be sensitive to sub-clinical changes. Histology of psoriasis skin lesions necessitate invasive skin biopsies. This indicates an unmet need for a non-invasive, objective and quantitative approach to assess disease severity serially. Herein, we employ multispectral Raster-Scanning Optoacoustic Mesoscopy (ms-RSOM) derived structural and microvascular functional imaging metrics to examine the lesional and non-lesional skin in psoriasis subjects across different severities and also evaluate the treatment outcome in a subject with topical steroids and biologics, such as adalimumab. ms-RSOM derived structural metrics like epidermal thickness and total blood volume (TBV) and microvascular functional information such as oxygen saturation (sO2) are evaluated by spectrally resolving the endogenous chromophores like melanin, oxy-, and deoxy-hemoglobin. Initial findings reveal an elevated sO2 and TBV with severity in lesional and non-lesional psoriasis skin, thus representing increasing inflammation. An increase in epidermal thickness is also noted with the degree of severity, corresponding to the inflammation and increased abnormal cell growth. As a marker to evaluate the treatment response, we observed a decrease in epidermal thickness, sO2, and TBV in a psoriasis patient post-treatment, which is consistent with the decrease in the PASI score from 4.1 to 1.9. We envision that ms-RSOM has a huge potential to be translated into routine clinical setting for the diagnosis of severity and assessment of treatment monitoring in psoriasis subjects.

Preliminary Clinical Experience with a Novel Optical–Ultrasound Imaging Device on Various Skin Lesions

A compact handheld skin ultrasound imaging device has been developed that uses co-registered optical and ultrasound imaging to provide diagnostic information about the full skin depth. The aim of the current work is to present the preliminary clinical results of this device. Using additional photographic, dermoscopic and ultrasonic images as reference, the images from the device were assessed in terms of the detectability of the main skin layer boundaries and characteristic image features. Combined optical-ultrasonic recordings of various types of skin lesions (melanoma, basal cell carcinoma, seborrheic keratosis, dermatofibroma, naevus, dermatitis and psoriasis) were taken with the device (N = 53) and compared with images captured with a reference portable skin ultrasound imager. The investigator and two additional independent experts performed the evaluation. The detectability of skin structures was over 90% for the epidermis, the dermis and the lesions. The morphological and echogenicity information observed for the different skin lesions were found consistent with those of the reference ultrasound device and relevant ultrasound images in the literature. The presented device was able to obtain simultaneous in-vivo optical and ultrasound images of various skin lesions. This has the potential for further investigations, including the preoperative planning of skin cancer treatment.

Efficacy and Safety of Different Formulations of Calcipotriol/Betamethasone Dipropionate in Psoriasis: Gel, Foam, and Ointment

Preparations containing calcipotriol combined with betamethasone dipropionate (in the forms of ointment, gel, and foam) are available for the topical treatment of psoriasis. This review summarizes the differences in the efficacy and safety of these formulations, as well as the preferences of patients with various forms of psoriasis (plaque, scalp, and nail psoriasis). It has been documented that foams provide higher bioavailability, resulting in increased efficacy in plaque psoriasis compared to ointments and gels. Gels or foams are preferred by patients for their different practical qualities (e.g., gels for “easy application”, and foams for “immediate relief”). The available data indicate that ointments may be the most effective formulation in nail psoriasis, and gels are preferred by patients with scalp psoriasis because of their cosmetic features. Treatment with a foam formulation is associated with a lower number of medical appointments compared to treatment with an ointment and with a lower probability of developing indications for systemic treatment. The safety profiles of foams, ointments, and gels are comparable, with the most common adverse effect being pruritus at the application site (in 5.8% of the patients). A long-term proactive maintenance therapy markedly reduces the number of relapses and is likely to close the gap between topical and systemic treatment in psoriasis.

Biophysical and ultrasonographic changes in pityriasis rosea compared with uninvolved skin

BACKGROUND

Pityriasis rosea (PR) is a common, self-limited, inflammatory papulosquamous skin disease with a possible viral etiology.

OBJECTIVE

The goal of this study was to evaluate skin biophysical properties in patients with PR compared with uninvolved skin to better understand the pathogenesis of PR.

METHODS

Stratum corneum hydration, transepidermal water loss, surface friction, pH, sebum, melanin, erythema, temperature, elasticity parameters (R0, R2, R5), thickness, and echodensity of the epidermis and dermis were measured on lesions of classic PR in 21 patients and compared with control sites (average of uninvolved perilesional and symmetrical skin) with a paired t test.

RESULTS

Stratum corneum hydration (p < .001), R0 (p = .003), R2 (p = .001), R5 (p = .003), and echodensity of the dermis (p = .006) were significantly lower, whereas transepidermal water loss (p = .001), pH (p < .001), and erythema (p < .001) were significantly higher in PR lesions. There was no significant difference in friction index, sebum, melanin content, temperature, thickness of the epidermis and dermis, and echodensity of the epidermis between PR and normal skin.

CONCLUSION

PR skin is characterized by certain alterations in biophysical properties, which are mostly correlated with histologic changes. These changes may be helpful in early, noninvasive diagnosis of PR.

Clinical Applications of In Vivo and Ex Vivo Confocal Microscopy

Confocal laser scanning microscopy (CLSM) has been introduced in clinical settings as a tool enabling a quasi-histologic view of a given tissue, without performing a biopsy. It has been applied to many fields of medicine mainly to the skin and to the analysis of skin cancers for both in vivo and ex vivo CLSM. In vivo CLSM involves reflectance mode, which is based on refractive index of cell structures serving as endogenous chromophores, reaching a depth of exploration of 200 μm. It has been proven to increase the diagnostic accuracy of skin cancers, both melanoma and non-melanoma. While histopathologic examination is the gold standard for diagnosis, in vivo CLSM alone and in addition to dermoscopy, contributes to the reduction of the number of excised lesions to exclude a melanoma, and to improve margin recognition in lentigo maligna, enabling tissue sparing for excisions. Ex vivo CLSM can be performed in reflectance and fluorescent mode. Fluorescence confocal microscopy is applied for “real-time” pathological examination of freshly excised specimens for diagnostic purposes and for the evaluation of margin clearance after excision in Mohs surgery. Further prospective interventional studies using CLSM might contribute to increase the knowledge about its application, reproducing real-life settings.

Dermoscopy in Monitoring and Predicting Therapeutic Response in General Dermatology (Non-Tumoral Dermatoses): An Up-To-Date Overview

Besides the well-known use in supporting the non-invasive diagnosis of non-tumoral dermatoses (general dermatology), dermoscopy has been shown to be a promising tool also in predicting and monitoring therapeutic outcomes of such conditions, with the consequent improvement/optimization of their treatment. In the present paper, we sought to provide an up-to-date overview on the use of dermoscopy in highlighting response predictor factors and evaluating therapeutic results in the field of general dermatology according to the current literature data. Several dermatoses may somehow benefit from such applications, including inflammatory conditions (psoriasis, lichen planus, dermatitis, granulomatous conditions, erythro-telangiectatic rosacea, Zoon balanitis and vulvitis, cutaneous mastocytosis, morphea and extra-genital lichen sclerosus), pigmentary disorders (vitiligo and melasma) and infectious dermatoses (scabies, pediculosis, demodicosis and viral warts).