The application of capillaroscopy in scalp imaging

The trichoscope is a key instrument in the field of trichology. It allows the detection of early problems and diseases of the scalp, and the selection of appropriate treatment methods. In some cases, it is necessary to perform extended diagnostics. Capillaroscopy enables to measure cutaneous vascularization and evaluate vascular changes. The study aimed to introduce the use of capillaroscopy in imaging of the scalp. The possibilities of diagnostic development on the way to assess the predictive value of vascular and hyperpigmented skin dermatoses were indicated. Capillaroscopy can complement the basic diagnosis and control of the skin and its appendages.


INTRODUCTION
The origins of capillaroscopy, and attempts to describe the circulatory system, date back to antiquity.The development of this method was linked to the improvement of lenses and the visibility of blood vessels.The first capillaroscopy examination of the nail shaft occurred in 1663 by Johan Christophorus Klhau [1].The 1970s brought important diagnostic advances in the field of rheumatology.At that time, the possibility of diagnosing the development of systemic scleroderma and rheumatic diseases by observing cutaneous vascularisation was demonstrated [1,2].Technological innovations enabled the cataloguing of the images obtained and also a videodiagnosis.Research is currently underway to further improve video capillaroscopy, which is attracting interest and recognition among scientists, specialists and physicians for its diagnostic capabilities.Rheumatologists and dermatologists have also paid particular attention to capillaroscopy.Education in the interpretation of video capillaroscopy enabled to creation of a diagnostic scale for Raynaud's disease, systemic scleroderma, and has also led to a wider observation and first clinical conclusions in the course of diabetes, skin diseases such as rosacea and psoriasis [1,3].

SCALP DIAGNOSTICS
The examination to assess and differentiate scalp lesions is referred to as trichological diagnostics [4][5][6][7].It is based on the use of methods such as trichoscopy, capillaroscopy, Wood's lamp and laboratory tests [2,[6][7][8].During a single visit, specialists often use several diagnostic methods to gather enough information about the client's scalp [6].
Trichoscopy is considered as a primary method [6,8].This is a non-invasive method of imaging the scalp using a microscope with an anti-reflective lens with magnifications ranging from 20 to as high as 700 times, depending on the apparatus.The trichoscopic apparatus is equipped with different light sources and colours, which are used to differentiate between healthy and diseased tissue, skin lesions, the functioning hair and sebaceous apparatus and skin characteristics.The most commonly used light types are polarised light, white light, ultraviolet light and fluorescent light [4,[8][9][10][11][12].
Capillaroscopy is a non-invasive method for diagnosing the form and pattern of cutaneous vascularisation.It is also excellent for anthropometry of cutaneous vascularisation.Two diagnostic techniques are used to assess the vasculature: the dry technique and the immersion technique.The immersion technique requires the use of immersion oil, which is an oily liquid applied to the client's skin during capillaroscopy [8,9].The main characteristic of immersion oil a specific refractive index, which is almost identical to the refractive index of glass.This allows for homogeneous oil immersion and virtually eliminates beam deflection, which greatly increases the efficiency of the lens, enabling accurate measurements of vascularisation, structureless areas and avascular fields [1,2,8,9].The capillaroscopy device has a larger field of view (FOV) function, which provides the ability to make precise image measurements in terms of colour quality, shape and size of the parameters under study.The range of image reception extends to the superficial plexus of cutaneous vascularisation [6,9].
Wood's lamp is a quartz lamp with a filter.It emits ultraviolet radiation (UV) with a bandwidth of 320 to 400 nm.It is utilised in cosmetological and dermatological diagnostics to identify ringworm, dermatitis, infections, and other skin conditions [3,4,12].
Laboratory tests are not conducted by the trichologist.However, they are complementary tests, performed at the point of sampling, to assess the state of health [4,9,12].

CAPILLAROSCOPY IN MEDICINE AND TRICHOLOGY
Capillaroscopy is used by clinicians to examine capillary morphology and microcirculation [1].Assessment is performed on the nail shafts of the hands and feet [1].It is most commonly used in the differentiation of primary and secondary Raynaud's signs.Capillaroscopy has been successful in detecting systemic scleroderma, and the use of capillaroscopy in autoimmune diseases is promising [1,10,13,14].An upgraded version of capillaroscopy and definitely more practical is videocapillaroscopy.It is a subtype of classical capillaroscopy in which capillary loops are assessed using a special movable head equipped with a rounded lens, a light source and a camera capable of zooming in up to 200 times and a 3D-like effect.
The capillaroscopy examination can be performed with an additional FOV, a movable head and a rounded lens, which complements the trichological diagnosis performed with the trichoscope.The actual images are of high quality in terms of colour, and measurements are taken to an accuracy of 0.02 mm [1,10].Parameter comparisons are shown in Table 1, while qualitative assessments were based on several office cases (Table 1, 2, 3).Normal skin colour, locally visible tree-shaped blood vessels.
Normal skin colour, locally visible tree-shaped blood vessels.
Visibility of the injured site Petechiae of a vivid red colour.A yellow secretion from the sebaceous gland is visible around the lesion.
Petechiae of a vivid red colour.A yellow secretion from the sebaceous gland is visible around the lesion.

Colour of a lesion
Brown-coloured melanocytes with well-defined microcapillaries in a tree-shaped vessel type, conquering the colour of the melanocytic lesion.Visible discolouration (line in the centre of the lesion).
Melanocytic lesion visible in one colour, visible treeshaped vessels slightly blurred, visually expanding their size.No visible brown colour of melanocytes.Visible discolouration (line in the centre of the lesion).
Other features Prominent dark hair shaft colour with hypopigmentation.Skin type cannot be assessed, hypopigmentation visible, hair colour less intense.
Source: Own elaboration

ADVANTAGES OF USING CAPILLAROSCOPY IN TRICHOLOGY
Epidermal and interfollicular assessment with a capillaroscope is performed using the dry method or the immersion method [1,10].In the dry method, the specialist obtains information on the degree of keratinisation, the quality of the hydro-lipid mantle and the function of the sebaceous and sweat glands.Immersion is used for anthropometry of capillary loops, the type of vascularisation in relation to a recognised scale closely related to the location on the scalp.The FOV light emphasises colour clarity, clearly marking the edges of vessels and lesions (they are not diffuse and deceptively dilated), allowing measurement of vascularisation, type and size of dots, pigmented lesions, hemangiomas, warts, avascular fields or differentiation of dermatoses based on skin colour, vascularisation type and scale size [10,11].The rounded head widens the angle of visibility.
In addition, the device is ideal for observing skin reaction at any time during trichological therapy.The diagnostic programme of the capialaroscope allows measurements to be taken using a grid with 1 mm intervals, a circular grid and a cross grid.The width, length or radius measurement functions are designed for the anthropometry of vascularisation, hair shafts and glands [10,11].
The imprecise colour quality and limited field of view can make the image of a melanocytic lesion on trichoscopy ambiguous or prevent accurate determination of the result.

SEMI-QUANTITATIVE TESTING
Using a semi-quantitative test, it is possible to assess the predictive value of dermatoses of the skin and its appendages.This test serves as a supplementary tool to the basic diagnosis and control of the skin and its appendages during the applied cosmetological-trichological therapy (Table 5).

Table 1
Qualitative evaluation of images obtained from capillaroscope and trichoscope in a woman with seborrhoeic dermatitis (SEA) in a quiescent state

Table 2
Qualitative evaluation of images obtained from capillaroscope and trichoscope in a man with type II diabetes mellitus Source: Own elaboration Aesthetic Cosmetology and Medicine 2 / 2024 / vol.13 Source: Own elaboration Table 3 Qualitative evaluation of the image obtained from the capillaroscope and trichoscope in a healthy 33-year-old man.Visible melanocytic nevus Capillaroscope Trichoscope Photo Skin lesion Melanocytic lesion.Melanocytic lesion.

Table 4
Comparison of selected skin features obtained by scalp imaging during practical application of diagnostic assessment Source: Own elaboration

Table 5
Semi-quantitative trichoscopic evaluation of the scalp performed in a man aged 35 years with a capillaroscope model MEDL4N-PRO alopecia, dysbiosis, heterogeneity and hypopigmentation of the hair shaft.The thickening of the vascularisation in the glomerular vessel type within the increased keratosis indicates local inflammation and the possibility of dermal dysbiosis.SUMMARYThe diagnostic development and innovative use of the capillaroscopy are aimed at preventing vascular and pigmentary diseases.By monitoring the appropriate responses of the cutaneous vasculature and exploring the potential for expanding the vascular scale, experts can obtain valuable data regarding alterations.The high quality of the actual images enables us to observe dysfunctions in the cutaneous vasculature, manifesting themselves as ischaemic factor, microangiopathy or macroangiopathy.Rapid diagnosis leads to the intervention of an appropriate specialist.The key to diagnosis lies in a skilful focus on the examination of individual skin features and the choice of equipment with the proper parameters.The complexity of diagnosis requires a combination of different examination methods.Due to the above, it is worthwhile to develop trichoscopy with several other parameters such as a larger field of view, colour saturation, precise calibration and image angle and vision of 3D-like quality, comparable to the one obtained by a capillaroscope.
Source: own elaborationFig.1 Frontal lobe Source: Own archive Fig. 2 Temporal lobe Source: Own archive Result of semi-quantitative examination: diffuse