P25 A METHODOLOGY STUDY COMPARING TRADITIONAL 35MM HAIR COUNTS TO AUTOMATED IMAGE ANALYSIS MEASUREMENTS, AND ASSESSING VISUALIZATION SENSITIVITY OF HAIR DYING WHEN QUANTIFYING HAIR LOSS IN MEN AND WOMEN WITH ANDROGENETIC ALOPECIA
Kohut B, Wanser R, Reardon R, Canfield W, Canfield D
Pfizer, Consumer Healthcare, Morris Plains, NJ; TKL Research, Paramus, NJ; Canfield Scientific, Inc., Fairfield NJ, USA

For approximately 20 years the "gold standard" for evaluating PHL/AGA (pattern hair loss/androgenetic alopecia) is 35mm macro-photography using standardized optical reproduction ratios designed to limit target area hair counts (TAHC) to non-vellus hairs utilizing a "photographic threshold". New digital image technologies using digital epiluminescence (ELP) and analysis software allow thresholding of hair thickness measurements for determining TAHC. This methodology study compared traditional 35mm macro-photography, measuring visualized TAHC, to computer-assisted non-vellus hair counts from digital photographs. Visualization sensitivity effects with hair dying were also explored. The study was conducted in men and women (n=7) with mild/moderate PHL At four time points in one day, both the standard 35mm camera system and digital ELP images were taken. Prior to baseline, a target site with decreased scalp hair density was prepared by clipping hairs to approximately 1 mm in length. At baseline and time two, photographs were taken without the use of hair dye. Prior to time three and four, the clipped hair was dyed prior to photography. All visualized hairs within 1 cm2 of scalp area on the 35mm color transparencies were manually mapped. TAHC was then generated using custom image analysis. Widths and TAHC in the digital images from ELP were recorded using a validated image analysis software system. Counts of visualized hair by 35mm were compared to the non-vellus hair counts (= 30 microns) from ELP. Results of this study showed that the traditional 35mm mean TAHC was 169.1 and the corresponding mean TAHC using ELP (hairs >30 microns) was 167.9. While the results of this study confirm that the visualized hairs recorded by 35 mm are hairs = 30 microns, the ELP technique offers other advantages such as specific data on hair thickness distributions.