High-frequency ultrasound biomicroscopy of the normal canine haired skin.

Background: The ultrasonographic appearance of the normal canine haired skin examined using high-frequency ultrasonography has not been described.

Hyposthesis/objectives: To describe the echogenicity of normal canine haired skin using high-frequency (50 MHz) ultrasonography and to compare ultrasonographic with histological measurements of skin thickness using snap-frozen tissue biopsy samples.

Animals: Ten normal healthy beagle dogs.

Methods: Ultrasonographic examination was performed on eight cutaneous sites by use of a 50 MHz polyvinylidene difluoride transducer. The skin echogenicity was evaluated, and the mean of 10 skin thickness measurements was calculated. Ultrasonography results were compared with histological findings of skin cryosections stained with haematoxylin and eosin, as well as with histometric measurements of skin thickness. Differences in the ultrasonographic and histological measurements among biopsy sites, age and sex of the animals were also examined.

Results: The skin layers and hair follicles could be identified with high-frequency ultrasound biomicroscopy in all eight examination sites of all 10 dogs. There was a highly significant, positive association between the ultrasonographic and histological measurements (P < 0.001) of skin thickness. For both ultrasonographic and histological skin thickness measurements, there were no statistically significant differences between sex, age or among the different examination sites.

Conclusions And Clinical Importance: Cutaneous ultrasound biomicroscopy using a 50 MHz transducer is a useful tool for the following applications: (i) to identify the skin layers (including the epidermis, dermis and subcutaneous fat); (ii) to demonstrate the hair follicles in various areas of the haired skin; and (iii) to measure the thickness of normal canine skin accurately.