title: Cross-section Trichometry: A Clinical Tool for Assessing the Progression and Treatment Response of Alopecia.
abstract: BACKGROUND
  To properly assess the progression and treatment response of alopecia, one must measure the changes in hair mass, which is influenced by both the density and diameter of hair. Unfortunately, a convenient device for hair mass evaluation had not been available to dermatologists until the recent introduction of the cross-section trichometer, which directly measures the cross-sectional area of an isolated bundle of hair.
  
  
  OBJECTIVE
  We sought to evaluate the accuracy and sensitivity of the HairCheck(®) device, a commercial product derived from the original cross-section trichometer.
  
  
  METHODS
  Bundles of surgical silk and human hair were used to evaluate the ability of the HairCheck(®) device to detect and measure small changes in the number and diameter of strands, and bundle weight.
  
  
  RESULTS
  Strong correlations were observed between the bundle's cross-sectional area, displayed as the numeric Hair Mass Index (HMI), the number of strands, the silk/hair diameter, and the bundle dry weight.
  
  
  CONCLUSIONS
  HMI strongly correlated with the number and diameter of silk/hair, and the weight of the bundle, suggesting that it can serve as a valid indicator of hair mass. We have given the name cross-section trichometry (CST) to the methodology of obtaining the HMI using the HairCheck(®) system. CST is a simple modality for the quantification of hair mass, and may be used as a convenient and useful tool to clinically assess changes in hair mass caused by thinning, shedding, breakage, or growth in males and females with progressive alopecia or those receiving alopecia treatment.
authors.affiliation: Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida 33136, USA.
authors.forename: Tongyu Cao
authors.initials: TC
authors.lastname: Wikramanayake
authors.forename: Lucia M
authors.initials: LM
authors.lastname: Mauro
authors.forename: Irene A
authors.initials: IA
authors.lastname: Tabas
authors.forename: Anne L
authors.initials: AL
authors.lastname: Chen
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Llanes
authors.forename: Joaquin J
authors.initials: JJ
authors.lastname: Jimenez
keywords: Hair density; hair diameter; hair mass; hair mass index; hair measurement