Standardization and Validation of Scalp Surface Area Measurement and Assessment of Interchangeability Between Two Independent Methodologies for Head Crown Area and Total Hair Count Measurement.
Level 4 - case-series / case-control
Cross-sectional method validation and comparison study
PubMed 41909352 · doi:10.7759/cureus.104173
What was done
A prospective, single-visit method-comparison study evaluated techniques for measuring scalp area and hair count in adults aged 18 to 55 years. Total scalp surface area was measured in 25 participants using a calibrated measuring tape. Head crown surface area, including frontal and mid-scalp regions, was measured in 25 participants using both a calibrated measuring tape and photographic image analysis with Image-Pro software. Hair counts from global 90° head photographs of 50 participants were compared between phototrichogram-based CASLite NOVA software and Image-Pro software. Agreement was evaluated using Bland-Altman analysis, intraclass correlation coefficients (ICC), and concordance correlation coefficients (CCC).
What was found
Mean scalp surface area was 492.36 ± 30.97 cm². For head crown area measurements, comparison between the measuring tape and Image-Pro analysis yielded an ICC of 0.75 and a CCC of 0.74, with minimal systematic bias reported on Bland-Altman analysis. Hair count comparisons between CASLite NOVA and Image-Pro were reported to show good agreement with small average differences and acceptable limits of agreement, though specific numerical values for hair counts, bias, and limits of agreement were not provided in the abstract.
Why it matters
The findings provide normative data for scalp surface area and support the interchangeable use of calibrated measuring tape and photographic image analysis for head crown area and hair count assessments in clinical and cosmetic research.
Limits
The sample size was small (n = 25 for area measurements, n = 50 photographic datasets for hair counts). Specific numerical data for hair counts, Bland-Altman bias, and exact limits of agreement were omitted from the abstract. Long-term reproducibility and inter-rater reliability across diverse scalp shapes or hair loss grades were not reported.
Cited by
- supports The human scalp contains approximately 70,000 to 100,000 hair follicles on average.