The authors discuss the choice of parameters for forearm photoageing assessment using high-frequency ultrasound.

Background Topical tretinoin cream is the gold standard treatment for skin ageing, particularly photoaging. The purpose of tretinoin peel was to obtain similar results, but in a shorter time, however, there have been few controlled trials on its effectiveness. Objective To compare efficacy and safety of tretinoin 0.05% cream and 5% as a peeling agent on photoaging and field cancerization of the forearms. Methods Clinical trial with therapeutic intervention, prospective, randomized (computer‐generated randomization list), parallel, comparative (intrasubject) and evaluator‐blinded (except for histology and immunohistochemistry), including 24 women (48 forearms) aged over 60 years who have not undergone hormone replacement and categorized as Fitzpatrick skin phototype II or III. The forearms of the participants were randomized for treatment with 0.05% tretinoin cream three nights a week, or 5% tretinoin peel every 2 weeks. The opinion of the participant, severity of photoaging, corneometry, profilometry, high‐frequency ultrasound, histology (haematoxylin–eosin and Verhoeff stainings) and immunohistochemistry (p53, bcl‐2, Ki67 and collagen I) were assessed. Results One participant dropped out. The mean photoaging score reduced 20% and the mean actinic keratosis (AK) count reduced 60% with no difference between treatments. Three efficacy parameters showed opposite effects between the tretinoin treatments (P < 0.05%): (i) thickness of the corneal layer decreased with 0.05% tretinoin and increased by 5%; (ii) dermis echogenicity increased by 0.05% and decreased by 5% and (iii) Ki67 expression increased by 0.05% and decreased by 5%. There was good tolerability for both regimens. Conclusion Tretinoin as a cream 0.05% or peeling (5%) is safe and effective for the treatment of moderate photoaging and forearm field cancerization. The cream was superior in improving ultrasonographic parameters of ageing. Peeling was shown a superior performance in the stabilization of field cancerization.

Ultrasound imaging has been increasingly used in dermatologic research over the past four decades. This paper aims to review its use as a disease severity and treatment efficacy assessment tool, with emphasis on the past five years. Quantitative parameters such as skin thickness, overall echogenicity, echogenicity distribution, dermal-subcutaneous interface length or area are used. The authors review skin aging, cellulite, striae, fillers, scleroderma, hypertrophic scar, wounds and psoriasis studies, and discuss correlation between sonographic findings and clinical assessment and/or validated scores. Data are still insufficient to support ultrasound imaging use as an unique efficacy assessment method in a trial, but favor that it is a valuable adjuvant assessment tool that brings objectiveness to subjective clinical assessment. Further studies and technology improvement will expand its applications in dermatology. KEYWORDS: dermatology • lipodystrophy • localized scleroderma • psoriasis • scars • skin aging • systemic scleroderma • ultrasonography • ultrasound biomicroscopy • wound healingUltrasonography has been used in medicine for more than 50 years and is one of the most frequently applied diagnostic tools. It is a noninvasive and non-ionizing method with a relatively low cost when compared with computed tomography and scintigraphic scanning techniques [1]. Alexander and Miller were the pioneers in the use of ultrasound (US) in dermatology since 1979 [2]. They demonstrated a15 MHz one-dimensional (A-scan) US equipment that measured the skin thickness with similar accuracy to the radiological techniquethe most accurate non-invasive method so far. Three years later its reproducibility and validation was shown, although the skin thickness determined in vitro was found to be greater than when in vivo determinations were made, probably due to the release of in vivo tension within the dermis [3].The 20 MHz bidimensional (B-scan) US units were first available in the 1980s, thanks to the emergence of mechanical transducers that enabled the cross-sectional imaging of the skin [4]. From then on, studies have evaluated its application in a range of skin conditions with different aims: disease severity and treatment response evaluation, adjunct diagnostic tool, tumor dimensions assessment and other uses. This paper reviews the state of art of US imaging in dermatologic research, focusing on its role as a disease severity and/or treatment efficacy assessment tool, with emphasis on the most frequently reported applications over the past five years. The use of US as a diagnostic tool or for tumor dimension assessment is not discussed here. ConceptsUS is a mechanically propagated wave with frequency above 20 kHz -the upper frequency limit of human hearing [5]. US transducers are made out of piezoelectric materials that generate acoustic energy when a voltage is applied to them. The US beam is transferred as a pulse from the transducer to the adjacent fluid or tissue and propagates as a wave, which can be reflected or refract...

Meaningful differences in the biophysical characteristics of the extensor and flexor faces of the forearms were detected. Because the non-invasive instrumental measurements correlated with clinical findings, they may represent useful tools to assess efficacy and safety of skin ageing treatments in clinical research.

Cellulite caused impact in quality of life. Poor correlation between objective measures and clinical evaluation was detected. Cellulite severity assessment is a challenge, and objective parameters should be optimized for clinical trials.