Reliable assessment of forearm photoageing by high-frequency ultrasound: a cross-sectional study.
OBJECTIVE
High-frequency ultrasound is a non-invasive tool used in skin ageing research to assess dermis thickness and echogenicity. This study evaluated the reliability of a range of high-frequency ultrasound parameters and tested their correlation with age and a validated clinical scale for the assessment of forearm skin photoageing; the difference between two body sites according to environmental exposition patterns was also investigated.


METHODS
Twenty-three volunteers aged 28-82 years were divided into three groups according to forearm photoageing degree. A 20 MHz ultrasound unit was used to obtain cross-sectional images of the skin by two trained investigators on two different sites: the dorsal forearm (chronically photoexposed skin) and the proximal medial arm (non-photoexposed skin). Several echogenicity parameters were studied for each skin compartment: total dermis, upper dermis and lower dermis, and the ratio between upper and lower dermis.


RESULTS
The intraclass correlation coefficient (for complete agreement) between investigators was higher for upper and total dermis echogenicity measures compared with the lower dermis. At the non-photoexposed site, the upper and lower dermis parameter ratio was better correlated with age. At the photoexposed area, total dermis parameters demonstrated higher correlations with clinical score.


CONCLUSIONS
The authors discuss the choice of parameters for forearm photoageing assessment using high-frequency ultrasound.
Dermatology Department, Universidade Federal de São Paulo - UNIFESP, R Borges Lagoa, 508, São Paulo, SP, 04038-001, Brazil.
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L de Caetano
Dermatology Department, Universidade Federal de São Paulo - UNIFESP, R Borges Lagoa, 508, São Paulo, SP, 04038-001, Brazil.
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Soares
Dermatology Department, Universidade Federal de São Paulo - UNIFESP, R Borges Lagoa, 508, São Paulo, SP, 04038-001, Brazil.
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Bagatin
Department of Dermatology and Radiotherapy, Universidade Estadual Paulista "Julio de Mesquita Filho" - UNESP, Campus Universitário de Rubião Jr., Botucatu, SP, 18618-000, Brazil.
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Miot
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005542:Forearm / Q000528:radiation effects*; D006801:Humans; D008027:Light; D008875:Middle Aged; D015595:Skin Aging; D014465:Ultrasonics
safety testing; skin ageing; skin physiology/structure; statistics; ultrasonography