Glossary
Overview
This glossary explains important terms related to TrichoScan, hair analysis and the standardized capture of hair parameters. The explanations are intentionally concise and easy to understand and are meant as orientation.
A – D
Anagen
Growth phase of the hair. Hairs in the anagen phase grow actively and are especially relevant for many questions in hair analysis.
Anagen/telogen ratio
Proportion of growing hairs (anagen) and resting hairs (telogen). This value can indicate changes in the hair cycle.
Dermatoscope
Optical device for an enlarged view of skin and hair. In connection with TrichoScan, it is used together with an (integrated) camera for standardized images of a small scalp area.
Cumulative thickness density
Metric that considers not only the number of hairs but also their thickness. Cumulative thickness density is an important parameter in studies and follow-up measurements.
E – H
Endpoint
Defined target parameter in a study. In the context of TrichoScan, for example, hair density, hair thickness or the anagen/telogen ratio can serve as endpoints.
Follicular unit
Natural group of one or more hairs emerging from neighboring follicles. It can be considered as its own parameter in the evaluation.
Phototrichogram
Method for the photographic capture of hair growth and the hair cycle. Methodologically, TrichoScan is based on the combination of image capture and digital evaluation.
Hair density
Number of hairs per defined area. It is one of the fundamental metrics in hair analysis.
Hair thickness / hair diameter
Thickness of a single hair. In TrichoScan evaluation, mean or median hair thickness can be used as a measurement value.
Brightness parameters
Measurement values describing the brightness and contrast of hairs or the relationship to the surrounding skin. Depending on the question, they can provide additional information.
K – R
Compatibility
Suitability of a device or system for use with TrichoScan. Decisive factors include image quality, lighting, focus and reproducible magnification.
Contact plate
Glass plate on the front side of the dermatoscope that is placed on the skin. This presses the hairs into one plane, which helps achieve sharp and standardized images and supports defined conditions at the measurement site.
Measurement site
The precisely defined area of the scalp where images are taken. For follow-up measurements, it is crucial to find the same measurement site again as accurately as possible. In studies, this site can be marked with a small, quickly fading tattoo.
Phototrichogram
See phototrichogram.
Reproducibility
Ability to repeat images and measurements under comparable conditions. It is a key prerequisite for robust follow-up data.
S – Z
SOP
Abbreviation for “Standard Operating Procedure”. It refers to a standardized workflow that ensures preparation, image capture and evaluation are carried out consistently.
Standardization
Uniform execution of all steps in the measurement, for example with respect to the measurement site, lighting, magnification and hair preparation.
Telogen
Resting phase of the hair. Hairs in the telogen phase do not grow actively and are shed later as part of the natural hair cycle.
Terminal hair
Thick, more strongly pigmented hair. Its counterpart is the finer vellus hair.
TrichoScan Research
Validated research version of TrichoScan for studies and scientific applications.
Trichogram
Classic method for assessing hair roots and the hair cycle. Depending on the application, it is complemented or replaced by image-based methods.
Vellus hair
Fine, usually shorter hair with a smaller diameter. The ratio of vellus to terminal hairs can be relevant in hair analysis.
Follow-up measurement
Comparison of several measurements over time. For TrichoScan, this is often more meaningful than a single snapshot.
Growth rate
Increase in hair length per unit of time. Depending on the program version and question, it can be captured as a parameter.