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  • 1.
    Bergstrand, Sara
    et al.
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Lindberg, Lars-Göran
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Internal Medicine.
    Lindén, Maria
    Mälardalen University, Västerås, Sweden.
    Lindgren, Margareta
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Blood flow measurements at different depths using photoplethysmography and laser Doppler techniques2009In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 15, no 2, p. 139-147Article in journal (Refereed)
    Abstract [en]

    Background/purpose: This study has evaluated a multi-parametric system combining laser Doppler flowmetry and photoplethysmography in a single probe for the simultaneous measurement of blood flow at different depths in the tissue. This system will be used to facilitate the understanding of pressure ulcer formation and in the evaluation of pressure ulcer mattresses.

    Methods: The blood flow in the tissue over the sacrum was measured before, during and after loading with 37.5 mmHg, respectively, 50.0 mmHg. The evaluation of the system consisted of one clinical part, and the other part focusing on the technicalities of the probe prototype.

    Results: An increase in blood flow while loading was the most common response, but when the blood flow decreased during loading it was most affected at the skin surface and the blood flow responses may be different due to depths of measurement. Reactive hyperaemia may occur more frequently in the superficial layers of the tissue.

    Conclusion: The study showed that the new system is satisfactory for measuring tissue blood flow at different depths. The laser Doppler complements the photoplethysmography, and further development of the system into a thin flexible probe with the ability to measure a larger area is required.

  • 2.
    Falk, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Primary Health Care Centres. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Unit of Research and Development in Local Health Care, County of Östergötland.
    Ilias, Michail
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Anderson, Chris
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences.
    Inter-observer variability in reading of phototest reactions with sharply or diffusely delineated borders2008In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 14, no 4, p. 397-402Article in journal (Refereed)
    Abstract [en]

    Background: In both clinical and experimental phototesting, naked eye assessment of erythema has been the main assessment parameter. As with all subjective assessment, variability in recorded results due to variable circumstances around the performance and reading of tests influences reliability and utility of data whether they be interpreted for an individual patient or for a group of research subjects.

    Methods: In the present study, variability in the reporting of diameter of ultraviolet B (UVB) erythema has been studied. The erythematous reactions were assessed by the naked eye and with the help of a millimetre-graded ruler by a group of dermatologists and dermatological trainees. Reaction size, objectively quantified by means of laser Doppler perfusion imaging (LDPI) using thresholding of the reaction perfusion, and known size of UVB provocation were used as yardsticks in order to quantify this variability.

    Results: Agreement between observers, against known size, was excellent for reactions with a sharp border, but for reactions with a diffuse or indistinct border there was a substantial inter-observer variability. This was also true for the comparison between naked-eye reading and LDPI assessment of the reaction size.

    Conclusion: It is concluded that if naked-eye readings are to be the outcome measurement, then provocations/protocols producing distinct borders are an advantage. If borders between provoked and unprovoked skin can be expected to be diffuse, i.e. part of a continuum of response, the use of objective, bioengineering techniques such as LDPI is required. Quantitative methods are also the basis for more detailed presentation and interpretation of test results including information on dose response above the minimal erythema dose.

  • 3. Fullerton, AB
    et al.
    Rode, J
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Studies of cutaneous blood flow of normal forearm skin and irritated forearm skin based on high-resolution laser Doppler perfusion imaging (HR-LDPI)2002In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 8, p. 32-40Article in journal (Refereed)
  • 4. Fullerton, Ann
    et al.
    Rode, Birgitte
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Skin irritation typing and grading based on laser Doppler perfusion imaging2002In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 8, p. 23-31Article in journal (Refereed)
  • 5.
    Hägerlind, Elisabeth
    et al.
    Region Östergötland, Local Health Care Services in Central Östergötland, Primary Health Care in Central County. Linköping University, Faculty of Medicine and Health Sciences.
    Falk, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Primary Health Care in Central County. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Löfstedt, Tommy
    Computational Solutions, Umeå, Sweden.
    Lindholm-Sethson, Britta
    Umeå Univ, Dept Chem, Umeå, Sweden.
    Bodén, Ida
    Ivida AB, Umeå.
    Near infrared and skin impedance spectroscopy - a possible support in the diagnostic process of skin tumours in primary health care.2015In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 21, no 4, p. 493-499Article in journal (Refereed)
    Abstract [en]

    BACKGROUND/PURPOSE: The global incidence of skin cancer has increased drastically in recent decades, especially in Australia and Northern Europe. Early detection is crucial for good prognosis and high survival rates. In general, primary care physicians have considerably lower sensitivity and specificity rates for detection of skin cancer, compared to dermatologists. A probable main reason for this is that current diagnostic tools are subjective in nature, and therefore diagnostic skills highly depend on experience. Illustratively, in Sweden, approximately 155 500 benign skin lesions are excised unnecessarily every year. An objective instrument, added to the clinical examination, might improve the diagnostic accuracy, and thus promote earlier detection of malignant skin tumours, as well as reduce medical costs associated with unnecessary biopsies and excisions. The general aim of this study was to investigate the usefulness of the combination of near infrared (NIR) and skin impedance spectroscopy as a supportive tool in the diagnosis and evaluation of skin tumours in primary health care.

    METHODS: Near infrared and skin impedance data were collected by performing measurements on suspect malignant, premalignant and benign tumours in the skin of patients seeking primary health care for skin tumour evaluation. The obtained data were analysed using multivariate analysis and compared with the diagnosis received by the conventional diagnostic process.

    RESULTS: The observed sensitivity and specificity rates were both 100%, when discriminating malignant and premalignant skin tumours from benign skin tumours, and the observed sensitivity and specificity for separating malignant skin tumours from premalignant and benign skin tumours were also 100%, respectively.

    CONCLUSION: The results of this study indicate that the NIR and skin impedance spectroscopy may be a useful supportive tool for the general practitioner in the diagnosis and evaluation of skin tumours in primary health care, as a complement to the visual assessment.

  • 6.
    Häggblad, Erik
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Petersson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ilias, Michail A.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Anderson, Chris D
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Dermatology and Venerology in Östergötland.
    Salerud, Göran
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    A diffuse reflectance spectroscopic study of UV-induced erythematous reaction across well-defined borders in human skin2010In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 16, no 3, p. 283-290Article in journal (Refereed)
    Abstract [en]

    Introduction The colour of tissue is often of clinicaluse in the diagnosis of tissue homeostasis andphysiological responses to various stimuli.Determining tissue colour changes and borders,however, often poses an intricate problem and visualexamination, constituting clinical praxis, does notallow them to be objectively characterized orquantified. Demands for increased inter- and intraobserverreproducibility have been incentives for theintroduction of objective methods and techniques fortissue colour (e.g. erythema) evaluation. The aim ofthe present paper was to study the border zone of anUVB provoked erythematous response of humanskin in terms of blood volume and oxygenationmeasured by means of diffuse reflectancespectroscopy using a commercial probe.

    Material and Methods A provocation model, basedon partial masking of irradiated skin areas, definestwo erythema edges at every skin site responding tothe UV irradiation. In every subject, 5 test sites wereexposed with a constant UV light irradiance (14mW/cm2), but with different exposures times (0, 3,6, 9, 12 seconds). An analysis of the spectral datameasured across the two edges was performed for every scan line. The oxygenized and deoxygenizedhemoglobin contents were estimated in everymeasurement point, using a modified Beer-Lambertmodel.

    Results The fit of the experimental data to the model derived by the modified Beer-Lambert law was excellent (R2>0.95). Analyzing data for the chromophore content showed that the erythematous response in provoked areas is dominated by the increase in oxyhemoglobin. The width for the left and right border zone was estimated to 1.81±0.93 mm and 1.90±0.88 mm respectively (M±SD). The unprovoked area between the two edges was estimated to 0.77±0.68 mm.

    Conclusion While the chosen data analysis performed satisfactory, the ability of the probe design to differentiate spatial aspects of a reaction with abrupt borders was found to be suboptimal resulting in a probable overestimation of the erythematous edge slope. Probe modification or imaging are possible solutions.

  • 7.
    Ilias, Michail A.
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Anderson, Chris
    Linköping University, Department of Biomedicine and Surgery, Dermatology. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Single exposure phototesting utilizing a divergent ultraviolet beam1999In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 5, no 4, p. 255-259Article in journal (Refereed)
    Abstract [en]

    Background/aims: Confident diagnosis of photosensitivity in patients with light dermatoses requires skin exposure to well determined ultraviolet (UV) light doses, most often from a solar simulator. The traditional test procedure results in a rough classification of skin sensitivity based on the minimal erythema dose (MED) found for each patient. The limited number of constant irradiance doses used during phototesting decreases the precision of the MED value. In the present study we aimed at developing the technical system for the determination of MED by using a single, centrifugally attenuating, UVB provocation.

    Methods: A divergent UV beam was achieved with the help of an optic lens. To investigate the irradiance profile, an irradiance acquisition system was built that produced three-dimensional intensity maps. In addition, a laser Doppler perfusion imaging (LDPI) system was introduced in the evaluation of the skin response along with visual readings of the same exposed areas, in order to add a quantitative aspect to the assessment of erythema. The procedure was used on one test subject.

    Results: The divergent UV beam showed the desired profile. With the current setup 20 different UV-dose levels could be discriminated. Relevant UV-dose levels were determined and tested on a subject, which in practice gave results in the form of visual assessment as well as LDPI-images. The visual or LDPI diameter gave the MED. Within the skin reaction, irradiance and the laser Doppler values could be compared mm for mm.

    Conclusions: A more accurate MED determination with a single UV exposure seems to be feasible by using the proposed method. Though further investigation is required, the technique appears to offer new possibilities for the association of dose to response. In addition LDPI is possibly a useful complement to the visual readings of the skin responses, since the method gives a quantification of the grade of erythema, as opposed to visual (+, ++, +++) readings that are subjective and at best semiquantitative.

  • 8.
    Ilias, Michail
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Stücker, M.
    Department of Dermatology, Ruhr University, Bochum, Germany.
    Anderson, Chris
    Linköping University, Department of Biomedicine and Surgery, Dermatology. Linköping University, Faculty of Health Sciences.
    Salerud, Göran
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Assessment of pigmented skin lesions in terms of blood perfusion estimates2004In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 10, no 1, p. 43-49Article in journal (Refereed)
    Abstract [en]

    Background/aims: Cutaneous malignant melanoma is a disease of increasing clinical and economical importance. The prognosis is good with early diagnosis. The chief differential diagnosis is benign melanocytic naevus, a common lesion in Caucasians. Attempts have been made to use bioengineering techniques to aid in the initial diagnosis. The present study proposes a method of extracting possibly discriminative blood perfusion properties in pigmented skin lesions by combining information on the lesions' blood perfusion with optical or visual information of their spatial extent.

    Methods: A total of 46 blood perfusion measurements were performed on 22 pigmented skin lesions, the ultimate diagnosis of which was three histologically proven malignant melanomas, four histologically proven benign naevi and fifteen naevi assessed by two specialist dermatologists as being benign. Laser Doppler perfusion imaging gave two different types of two-dimensional data sets (64×64 pixels), one representing the total backscattered light intensity at each measurement point (TLI image) and the second corresponding to perfusion values. The boundaries of each examined lesion were derived from the TLI image employing greyscale thresholding, thus resulting in an estimated region of interest (ROI) approximating the optical extent of the lesion. The ROI was superimposed on the perfusion image and extraction of perfusion features was then performed.

    Results: The processing of the TLI images was successful in delineating the lesions' boundaries. The first hypothesis that the mean perfusion quotients in MM and benign naevi are equal could not be rejected at the chosen 5% level of significance. The second hypothesis that the mean percent-age of elevated perfusion values (image pixels) within the ROI shows no difference between MM and benign naevi could be rejected at a 5% level of significance.

    Conclusions: This study has presented a method of extracting blood perfusion parameters of pigmented skin lesions by combining blood perfusion information with information on the lesion's optical extent. The proposed method of presenting data could prove to be a useful discriminative adjunct in the assessment of pigmented skin lesions.

  • 9. Ivens, U.
    et al.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    O'goshi, K.
    Allergy patch test reading from photographic images: Disagreement on ICDRG grading but agreement on simplified tripartite reading2007In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 13, no 1, p. 110-113Article in journal (Refereed)
    Abstract [en]

    Background/aims: The International Contact Dermatitis Research Group (ICDRG) system for clinical scoring of allergic patch test reactions is well established in clinical dermatology for detailed scoring of allergic reactions. The degree of redness and the presence of swelling, papules, vesicles and bullae are assessed based on visual examination and palpation of reactions. In photographic assessment used in research and tele-dermatology, the scoring is solely based on visual examination of photos. The aim of the study was to evaluate inter-expert variation in patch test reading using photographic images, with ICDRG reading as a reference. Material and methods: Five experienced senior dermatologists each scored 55 positive patch test reactions from 16 slides in an office environment. The slides showed pictures of patch tests with different allergens. The scoring system by ICDRG with six categories for scoring was used. Results: The five dermatologists performed the scoring very differently. When the scoring system was simplified to a tripartite scoring system, the scoring was performed almost similarly by the five clinicians. Conclusion: Based on the present results, it is proposed that the number of scoring categories should be minimized and simplified into negative (including doubtful) reactions, positive reactions and irritant reactions. Such simplified tripartite reading is proposed for research purposes and for tele-dermatology, when scoring is based on photographic images. © Blackwell Munksgaard 2007.

  • 10. Lindén, Maria
    et al.
    Andersson, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Anderson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Is vascular reactivity in skin predictable?2000In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 6, no 1, p. 27-30Article in journal (Refereed)
    Abstract [en]

    Background/aims: Cutaneous microdialysis can be used to follow the pharmacology and metabolism of an inflammatory reaction. It is assumed that an equilibration period compensates for the trauma of catheter insertion. Methods: In the present paper, the vascular reactivity of the skin to histamine was tested using assessment by laser Doppler perfusion imaging. In a group of six subjects, the provocation was preceded by insertion of a microdialysis catheter. In a second control group, histamine provocation alone was performed (six subjects). Results: The vascular response to histamine was greater in the microdialysis catheter group than the control group. The histamine provocation caused a greater response than catheter insertion. Further, there was a correlation between the response to catheter insertion and the histamine provocation. Conclusion: It appears that the insertion and/or presence of a microdialysis catheter increases vascular reactivity to subsequent provocation. The response to catheter insertion may predict skin reactivity in general in the individual subject. (C) Munksgaard, 2000.

  • 11.
    Lindén, Maria
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Andersson, T
    Anderson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of dermatology and venereology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    High resolution laser Doppler perfusion imaging for the investigation of blood circulatory changes after microdialysis probe insertion1997In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 3, p. 227-232Article in journal (Refereed)
  • 12. Lodén, M
    et al.
    Andersson, A-C
    Andersson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Frödin, Thomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Öhman, Hans
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Lindberg, M
    Instrumental and dermatologist evaluation of the effect of glycerine and urea on dry skin in atopic dermatitis2001In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 7, no 4, p. 209-213Article in journal (Refereed)
    Abstract [en]

    Background/aims: Moisturising creams are useful treatment adjuncts in inflammatory dermatoses and have beneficial effects in the treatment of dry, scaly skin. The effects on dryness and skin permeability of a new moisturising cream with 20% glycerine was compared with its placebo and with a medicinally authorised cream with 4% urea (combined with 4% sodium chloride) in the treatment of dry skin. Methods: Patients (n=109) with atopic dermatitis were treated for 30 days with a moisturiser in a randomised, parallel and double-blind fashion. Transepidermal water loss (TEWL) and skin capacitance were assessed instrumentally, and changes in the dryness of the skin were assessed by the dermatologist. Results: No difference in TEWL was found between glycerine treatment and its placebo, whereas a lower value was found in the urea-treated area compared to the glycerine-treated area. No difference in skin capacitance was found. The clinical assessment of dryness showed urea to be superior to glycerine in treating the condition. Conclusions: Moisturising creams are different, not only with respect to composition but also with respect to their influence on skin as a barrier to water in patients with atopic dermatitis.

  • 13.
    Nilsson, Gert
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zhai, Hongbo
    P Chan, Heidi
    University of California.
    Farahmand, Sara
    University of California.
    Maibach , Howard I
    University of California.
    Cutaneous bioengineering instrumentation standardization: the Tissue Viability Imager2009In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 15, no 1, p. 6-13Article in journal (Refereed)
    Abstract [en]

    Tissue Viability Imaging (TiVi) is a new bioengineering technology intended for remote two-dimensional mapping of skin red blood cell concentration (RBCconc). Before use in the laboratory, work-site and dermatology clinic, critical performance parameters of this emerging technology require careful evaluation.

    To assess short- and long-term stability, image uniformity, distance and image size dependence, ambient light and curvature influence in a production batch of Tissue Viability Imagers.

    Four Tissue Viability Imagers from the same production batch were evaluated at two laboratories (one industrial and one dermatological) with respect to critical parameter performance.

    The average systematic drift in sensitivity over time was 0.27% and < 1.02% for all four units tested. Difference in sensitivity between units was limited to 4.1% and was due to offset rather than gain deviation. Spatial variation in image uniformity was below 3.08% and 1.93% in the corners and centre of an individual image, respectively. This spatial variation could be further reduced to 0.25% and 0.13%, respectively by image normalization. Ambient light from a 40 W bulb or a 11 W fluorescent light source at a distance of 50-60 cm above the object, reduced the recorded values by about 10%, while the camera to object distance and image size had no detectable influence on sensitivity. Curved objects, such as human forearm, demonstrated an edge effect limited to below 10%.

    The critical TiVi performance parameters evaluated proved stable in relation to expected variations in skin RBCconc over time. Calibration by way of a two-point method may reduce differences in sensitivity between instruments to further facilitate inter-laboratory comparison of results.

  • 14.
    O'doherty, Jim
    et al.
    Department of Physics, University of Limerick, Plassey Technological Park, Limerick, Ireland.
    Henricson, Joakim
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine.
    Anderson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Leahy, Martin J.
    Department of Physics, University of Limerick, Plassey Technological Park, Limerick, Ireland.
    Nilsson, Gert
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Sjöberg, Folke
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Burn Unit . Östergötlands Läns Landsting, Reconstruction Centre, Department of Plastic Surgery, Hand surgery UHL.
    Sub-epidermal imaging using polarized light spectroscopy for assessment of skin microcirculation2007In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 13, no 4, p. 472-484Article in journal (Refereed)
    Abstract [en]

    Background/aims: Many clinical conditions that affect the microcirculation of the skin are still diagnosed and followed up by observational methods alone in spite of the fact that non-invasive, more user-independent and objective methods are available today. Limited portability, high cost, lack of robustness and non-specificity of findings are among the factors that have hampered the implementation of these methods in a clinical setting. The aim of this study is to present and evaluate a new, portable and easy-to-use imaging technology for investigation of the red blood cell (RBC) concentration in the skin microvasculature based on the method of polarization light spectroscopy using modified standard digital camera technology.

    Methods: The use of orthogonal linear polarization filters over both the flash source and the detector array removes the polarization-retaining light reflected from the epidermal layer. Only the depolarized light backscattered from the papillary dermal matrix reaches the detector array. By separating the RGB color planes of an image acquired in this manner and applying a dedicated image processing algorithm, spectroscopic information about the chromophores in the dermal tissue can be attained. If the algorithm is based on a differential principle in which the normalized differences between the individual values of the red and green color plane are calculated, tissue components with similar spectral signature in both planes are suppressed, while components with different spectral signatures such as RBCs are enhanced.

    Results: In vitro fluid models compare well with theory and computer simulations in describing a linear relationship between the imager output signal termed the tissue viability index (TiVi index) and RBC concentration in the physiological range of 0-4% RBC fraction of tissue volume (cc=0.997, n=20). The influence of oxygen saturation on the calculated RBC concentration is limited to within -3.9% for values within the physiological range (70-100% oxygen saturation). Monte Carlo simulations provide information about the sampling depth (about 0.5mm on the average) of the imaging system. In vivo system evaluation based on iontophoresis of acetylcholine displays a heterogeneous pattern of vasodilatation appearing inside the electrode area after about 10min. Topical application of methyl nicotinate and clobetasol propionate further demonstrates the capacity to document the extent and intensity of both an increase (erythema) and a decrease (blanching) in the skin RBC concentration without movement artifact and with compensation for irregularity in pigmentation.

    Conclusions: Polarization light spectroscopy imaging for assessment of RBC concentration in the skin microvasculature is a robust and accessible technique for the clinical setting. Additionally, the technique has pre-clinical research applications for investigation of the spatial and temporal aspects of skin erythema and blanching as well as a potential role in drug development, skin care product development and skin toxicological assessment.

  • 15.
    ODoherty, Jim
    et al.
    St Thomas Hospital, England .
    Henricson, Joakim
    Linköping University, Department of Clinical and Experimental Medicine, Surgery. Linköping University, Faculty of Health Sciences.
    Falk, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Anderson, Chris
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Dermatology and Venerology.
    Correcting for possible tissue distortion between provocation and assessment in skin testing: The divergent beam UVB photo-test2013In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 19, no 4, p. 368-374Article in journal (Refereed)
    Abstract [en]

    BackgroundIn tissue viability imaging (TiVi), an assessment method for skin erythema, correct orientation of skin position from provocation to assessment optimizes data interpretation. Image processing algorithms could compensate for the effects of skin translation, torsion and rotation realigning assessment images to the position of the skin at provocation. less thanbrgreater than less thanbrgreater thanMethodsA reference image of a divergent, UVB phototest was acquired, as well as test images at varying levels of translation, rotation and torsion. Using 12 skin markers, an algorithm was applied to restore the distorted test images to the reference image. less thanbrgreater than less thanbrgreater thanResultsThe algorithm corrected torsion and rotation up to approximately 35 degrees. The radius of the erythemal reaction and average value of the input image closely matched that of the reference images true value. less thanbrgreater than less thanbrgreater thanConclusionThe image de-warping procedure improves the robustness of the response image evaluation in a clinical research setting and opens the possibility of the correction of possibly flawed images performed away from the laboratory setting by the subject/patient themselves. This opportunity may increase the use of photo-testing and, by extension, other late response skin testing where the necessity of a return assessment visit is a disincentive to performance of the test.

  • 16.
    Ogoshi, Ken-ichiro
    et al.
    Bispebjerg Hospital, Copenhagen.
    Serup, Jörgen
    Bispebjerg Hospital, Copenhagen.
    Safety of sodium fluorescein for in vivo study of skin2006In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 12, no 3, p. 155-161Article in journal (Refereed)
    Abstract [en]

    Background/purpose: Epicutaneous labeling or intradermal injection of the fluorescent sodium fluorescein is being used increasingly to investigate skin conditions in vivo when using non-invasive devices such as confocal scanning laser microscopy. Sodium fluorescein was used intravenously for decades for the examination of the vasculature of the ocular fundus (fluorescein angiography) and as eye drops for diagnosis of corneal erosions. The objective of this article is to systematically review the literature on fluorescein and conclude its safety in cutaneous research to support research planning and evaluations by ethics committees.

    Methods: A number of databases and the literature about safety and toxicity of fluorescein in animal and human studies were searched and analyzed.

    Results: Side effects or adverse events reported in the literature were related to intravenous bolus injection. Transient nausea and vomiting may occur. Other adverse events such as vasovagal reaction, cardiac or respiratory effects and anaphylaxes are extremely rare but may be fatal. Intradermal injection may cause mild itch or pain; systemic adverse event was reported. Epicutaneous labeling is associated with no reported problem. A typical local dose is several magnitudes of order smaller than a typical intravenous dose.

    Conclusion: Fluorescein has been used for many years in medicine for diagnostic purposes and is widely safe, albeit intravenous bolus injection may cause serious adverse reactions. In the literature, we could not trace reports of local or systemic side effects of topical sodium fluorescein except itch and pain on intradermal injection, however, dependent on the fluorescein preparation used. Local dermal application of fluorescein for in vivo study of skin may be considered widely safe.

  • 17. Ogoshi, Ken-ichiro
    et al.
    Suihko, Christian
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of dermatology and venereology.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of dermatology and venereology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    In vivo imaging of intradermal tattoos by confocal scanning laser microscopy2006In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 12, no 2, p. 94-98Article in journal (Refereed)
    Abstract [en]

    Background/aims: In vivo confocal laser scanning microscopy (CLSM) is a new method for high-resolution imaging of intact skin in situ. Horizontal mapping of the outer skin is provided (magnification × 1000). Objectives: Tattooing is popular all over the world, however, tattooed skin has not been studied in using CLSM. Results: Tattoos in two volunteers were studied using the Vivascope1500® of Lucid Inc. Subepidermal massive deposits of dense, clustered pigment granules up to about 3 μm in size corresponding to black tattoos, and more scarce and diffuse deposits, corresponding to red, blue and green tattoos, were observed. Diffuse pigment granules tended to accumulate in the outer dermis underneath the level of the basement membrane zone. Conclusion: Dermal pigments from tattoos can be imaged in vivo using CLSM. This application of CLSM has an important future potential for pre-evaluation of tattoos before laser removal, predicting good or poor outcome of laser removal. Copyright © Blackwell Munksgaard 2006.

  • 18.
    O'Goshi, K.-I.
    et al.
    Department of Dermatology, Bispebjerg Hospital, DK-2400 Copenhagen, Denmark.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Inter-instrumental variation of skin capacitance measured with the Corneometer®2005In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 11, no 2, p. 107-109Article in journal (Refereed)
    Abstract [en]

    Background/purpose: Measurement of skin surface and stratum corneum (SC) hydration during clinical and/or experimental trials needs devices with acceptable reproducibility and sensitivity under conditions ranging from increased and normal to low hydration. A previous study comparing Corneometer® instruments (European group for Efficacy Measurement of Cosmetics and Other products - EEMCO) used for measurement of electrical capacitance of skin indicated a major difference among Corneometer® instruments. The aim of this study was to assess threee inter-instrumental similar Corneometer® instruments (two pieces of CM820 and one CM810) in normal skin. We named them CM-A(CM820), CM-B(CM820), and CM-C(CM810). Methods: The hydration state of SC measured as electrical capacitance of six body sites were measured in 53 subjects with three Corneometer® instruments. Result: We found that the Corneometer® instruments displayed close capacitance levels. When one Corneometer® was plotted against another the regression line indicated a good correlation among instruments albeit a major and random disagreement could appear in individual sites as an exception. Conclusion: Three Corneometer® instruments evaluated in this study gave close measurements and correlated well. Nevertheless, pretest validation of instruments should be undertaken in multicenter studies where capacitance data are compared or pooled, and concordance among instruments should be documented prior to study. © Blackwell Munksgaard, 2005.

  • 19.
    Said, Lilian
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Dermatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Rebel, Carl
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry.
    Epidermal calcium release (ECR) in vivo sampled with a simple washout chamber technique. Experimental studies in normal and barrier pertubated skin2002In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 8, no 4, p. 219-226Article in journal (Refereed)
    Abstract [en]

    Background/aims: Epidermis forms the protective barrier of the skin by its outermost layer, stratum corneum. The purpose of this study was to investigate the epidermal barrier in view of epidermal calcium release (ECR), phosphate release, transepidermal water loss (TEWL) and skin surface pH. Calcium is mainly an intracellular ion. Calcium was sampled introducing a new and simple washout chamber technique for the study of epidermal release in vivo. Methods: Test sites on forearms of 13 healthy subjects were pre-treated with 24 h water occlusion, 24 h 2% sodium lauryl sulphate (SLS) or tape stripped. Both untreated and pretreated test sites were exposed to a water washout chamber with 200╡ deionized water as a solvent. Water washout chambers were removed after two hours and calcium and phosphate in the water was analyzed. Transepidermal water loss and pH were measured before and after the trial. Results: pH increased after tape stripping and after exposure to SLS. Transepidermal water loss increased significantly at all test sites. Calcium was significantly released from SLS-treated sites but not from tape stripped sites. There was generally a correlation between ECR, phosphate release, TEWL and pH. In this study ECR is showed to be a barrier marker of high reproducibility. Conclusions: Epidermal calcium release or ECR is found useful as an indicator of skin barrier function. Calcium release and increase of pH appear mainly to illustrate direct and corrosive damage to epidermal cells and functions contrasting TEWL, in this experiment probably reflecting intercellular damage of fracturing as exemplified by mechanical damage resulting from surface stripping. This new distinction of skin barrier damage into cellular damage resulting from a corrosive chemical trauma and intercellular damage and fracturing resulting from a mechanical trauma is exemplified in SLS provocative testing and tape stripping, the former characterized by increased ECR. The washout chamber technique was deemed technically reliable and reproducible, and has a major potential in experimental dermatology and skin pharmacology for the study of in vivo epidermal release of a range of endogenous and exogenous substances.

  • 20.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Efficacy testing of cosmetic products2001In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 7, no 3, p. 141-151Article in journal (Refereed)
    Abstract [en]

    Background/aims: Regulations for cosmetic products primarily address safety of the products that may be used by large populations of healthy consumers. Requirements for documentation of efficacy claims are only fragmentary. This synopsis aims to review and conclude a set of standards that may be acceptable to the European Community, and the cosmetic industry, as a legal standard for efficacy documentation in Europe in the future. Methods and Results: Ethical, formal, experimental, statistical and other aspects of efficacy testing are described, including validation, quality control and assurance. The importance of user relevant clinical end points, a controlled randomized trial design and evidence-based cosmetic product documentation, validation of methods, statistical power estimation and proper data handling, reporting and archiving is emphasized. The main principles of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) good clinical practice (GCP) should be followed by the cosmetics industry in a spirit of good documentation standard and scientific soundness, but full GCP is not considered mandatory in the field of cosmetics. Documentation by validated bio-instrumental methods may be acceptable, but efficacy documentation based on information about raw materials, reference to literature and laboratory experiments are only acceptable in exceptional cases. Conclusions: Principles for efficacy substantiation of cosmetic products in Europe, as described in this synopsis, are officially proposed by the Danish Ministry of Environment and Energy to the European Community as a basis for an amendment to the Cosmetics Directive or otherwise implemented as a European Community regulation.

  • 21.
    Suihko, Christian
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology. Linköping University, Faculty of Health Sciences.
    Serup, Jorgen
    Bispebjerg Hospital, Denmark .
    Fluorescent fibre-optic confocal imaging of lesional and non-lesional psoriatic skin compared with normal skin in vivo2012In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 18, no 4, p. 397-404Article in journal (Refereed)
    Abstract [en]

    Background/aims Fibre-optic confocal imaging (FOCI) allows non-invasive visualization of live skin in vivo. A contrast agent, a fluorophore, is injected in the dermis. FOCI images are optical sections from a horizontal (en face) view. The aim was to study epidermis and the cellular structure of keratinocytes of psoriatic plaques and adjacent non-lesional with healthy skin as a reference. Methods Twelve patients with stable plaque psoriasis were studied and compared with a control group of eight healthy individuals. Fluorescein sodium was used as fluorophore. A hand held fibre-optic laser scanner (Stratum (R); Optiscan Pty., Melbourne, Australia) was used. The study included morphometric analyses. Results The confocal in vivo images demonstrated characteristic features of epidermis and keratinocytes in lesional and non-lesional skin vs. healthy skin. Morphometry based on FOCI demonstrated an approximately 30% increased width of keratinocytes of psoriatic skin vs. healthy control, and the number of keratinocytes per viewing field was reduced. FOCI allowed non-invasive visualization of cell nuclei and parakeratosis of psoriatic epidermis. The horizontal width of dermal papillae of psoriatic skin was increased by approximately 50% as compared with healthy skin, and the flow of erythrocytes in the papillar vessels could be observed in real-time. Conclusion FOCI can directly visualize essential epidermal structures of plaque psoriasis in vivo, in real-time and with cellular resolution without the need of taking biopsies and thus without disturbing the natural state of the skin. FOCI is a versatile future tool for non-invasive microscopic diagnosis and therapy follow-up of psoriasis.

  • 22.
    Suihko, Christian
    et al.
    Linköping University, Faculty of Health Sciences.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Fluorescence confocal laser scanning microscopy for in vivo imaging of epidermal reactions to two experimental irritants2008In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 14, no 4, p. 498-503Article in journal (Refereed)
    Abstract [en]

    Background: Fibre-optic fluorescence confocal laser scanning microscopy (CLSM) is a novel non-invasive technique for in vivo imaging of skin. The cellular structure of the epidermis can be studied. A fluorophore, e.g. fluorescein sodium, is introduced by an intradermal injection or applied to the skin surface before scanning. Images are horizontal optical sections parallel to the skin surface. Fluorescence CLSM has hitherto not been applied to experimental contact dermatitis. Objective: The aim was to study the applicability of fluorescence CLSM for in situ imaging of irritant contact dermatitis reactions caused by established model irritants, e.g. sodium lauryl sulphate (SLS) and pelargonic acid (PA). Methods: Twelve healthy individuals volunteered. The flexor aspect of the right and the left forearm was exposed to SLS in water and PA in isopropanol and occluded under Finn Chambers for 24h. The reactions were rated clinically and, following epicutaneous and intra-dermal application of fluorescein sodium, studied by fluorescence CLSM, magnification ×1000. Results: Both irritants disturbed the epidermal intercellular borders, which became blurred, thickened and variably altered. This was interpreted as being a result of chemical damage to cellular membranes. Cell borders might show a double contour as a result of inter-cellular oedema. PA might increase the size of individual keratinocytes interpreted as a result of intra-cellular disturbance with oedema. SLS-exposed sites showed clusters of keratinocytes with visible nuclei in the outer layers of the epidermis, e.g. a parakeratotic shift supposed to be due to increased cell proliferation elicited by SLS. The isopropanol vehicle and PA did not interfere with the CLSM imaging technique or the experimental procedures. SLS, being a detergent, however, modified the physico-chemical properties of the skin surface and both disturbed epicutaneous labelling with the flurophore and immersion oil coupling between the skin surface and the optical system. Thus, SLS was technically more difficult to study by CLSM than PA. Conclusions: This preliminary study demonstrated the applicability of fluorescence CLSM for a detailed study of experimental skin irritants in vivo. Essential findings were disturbed and widened cell borders, swelling of keratinocytes by PA and induction of a parakeratotic shift by SLS with clusters of keratinocytes holding nuclei in the epidermis. Fluorescence CLSM offers a unique opportunity to study the inter- and intracellular water compartments directly in the epidermis in situ and an opportunity to visualize cell proliferation manifested as parakeratosis. Fibre-optic fluorescence CLSM of irritant reactions is, however, technically more complicated than reflectance CLSM and may not be applicable to any irritant. SLS applied epicutaneously interacted with the skin surface and coupling to the microscope and was thus found to be more difficult to study technically than PA. PA dissolved in isopropanol is for technical reasons, and with SLS as alternative, considered the preferred model irritant. © Journal compilation © 2008 Blackwell Munksgaard.

  • 23. Suihko, Christian
    et al.
    Swindle, Lucinda D
    Thomas, Steven G
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of dermatology and venereology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Fluorescence fibre-optic confocal microscopy of skin in vivo: Microscope and fluorophores2005In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 11, no 4, p. 254-267Article in journal (Refereed)
    Abstract [en]

    Background/aims: Fibre-optic confocal imaging in vivo is a new approach in the assessment of human skin. The objective is to describe a novel instrument and its operation and use in combination with fluorophores. Methods: The Stratum® is a fibre-optic fluorescence confocal microscope especially developed for the study of skin and mucous membranes. The system is flexible and any body site can be studied with a hand-held scanner. The light source is a 488 nm argon ion laser. Horizontal (en face) images of the epidermis and outer dermis are produced with cellular resolution. Magnification is approximately 1000x. Fluorescein sodium is routinely used as fluorophore (intradermal injection or application to the skin surface). This fluorophore is safe for human use in vivo, but other substances (rhodamine B, Acridine Orange, green fluorescent protein, curcumin) have also been studied. Results: The instrument produces sharp images of epidermal cell layers from the epidermal surface to the sub-papillary dermis, with sub-cellular resolution. The scanner is flexible in use. The technique of intradermal fluorophore injection requires some skill. Conclusions: We consider this fibre-optic instrument a potentially important tool in skin research for non-invasive optical biopsy of primarily the epidermis. Present use is focussed on research applications, where the fluorophore distribution in the skin may illustrate morphological changes in the epidermis. © Blackwell Munksgaard, 2005.

  • 24.
    Tagami, H.
    et al.
    Department of Dermatology, Tohoku University, Tohoku, Japan.
    Serup, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Dermatology and Venerology . Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Hachiro Tagami, MD: Japanese dermatologist in a global community2003In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 9, no 1Other (Other academic)
    Abstract [en]

    [No abstract available]

  • 25.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Does low power laser light used in laser Doppler systems affect the sensory nerves1997In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 3, p. 233-236Article in journal (Refereed)
  • 26.
    Wårdell, Karin
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Andersson, T
    Anderson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of dermatology and venereology. Östergötlands Läns Landsting, Centre for Medicine, Department of Dermatology and Venerology in Östergötland.
    Analysis of laser Doppler perfusion images of experimental irritant skin reacsions1996In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 2, p. 149-157Article in journal (Refereed)
  • 27.
    Zhai, Hongbo
    et al.
    University of California.
    Chan, Heidi P
    University of California.
    Farahmand, Sara
    University of California.
    Nilsson, Gert
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Maibach , Howard I
    University of California.
    Comparison of tissue viability imaging and colorimetry: skin blanching2009In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 15, no 1, p. 20-23Article in journal (Refereed)
    Abstract [en]

    Operator-independent assessment of skin blanching is important in the development and evaluation of topically applied steroids. Spectroscopic instruments based on hand-held probes, however, include elements of operator dependence such as difference in applied pressure and probe misalignment, while laser Doppler-based methods are better suited for demonstration of skin vasodilatation than for vasoconstriction.

    To demonstrate the potential of the emerging technology of Tissue Viability Imaging (TiVi) in the objective and operator-independent assessment of skin blanching.

    The WheelsBridge TiVi600 Tissue Viability Imager was used for quantification of human skin blanching with the Minolta chromameter CR 200 as an independent colorimeter reference method. Desoximetasone gel 0.05% was applied topically on the volar side of the forearm under occlusion for 6 h in four healthy adults. In a separate study, the induction of blanching in the occlusion phase was mapped using a transparent occlusion cover.

    The relative uncertainty in the blanching estimate produced by the Tissue Viability Imager was about 5% and similar to that of the chromameter operated by a single user and taking the a(*) parameter as a measure of blanching. Estimation of skin blanching could also be performed in the presence of a transient paradoxical erythema, using the integrated TiVi software. The successive induction of skin blanching during the occlusion phase could readily be mapped by the Tissue Viability Imager.

    TiVi seems to be suitable for operator-independent and remote mapping of human skin blanching, eliminating the main disadvantages of methods based on hand-held probes.

  • 28.
    Zhai, Hongbo
    et al.
    University of California.
    Chan, Heidi P
    University of California.
    Farahmand, Sara
    University of California.
    Nilsson, Gert
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Maibach , Howard I
    University of California.
    Tissue viability imaging: mapping skin erythema2009In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 15, no 1, p. 14-19Article in journal (Refereed)
    Abstract [en]

    Tissue Viability Imaging (TiVi) is an emerging bioengineering technology intended for two-dimensional mapping of skin erythema and blanching. Before TiVi can be effectively used in studies of diseased or damaged skin, the variability in normal skin red blood cell concentration (RBCconc) requires evaluation.

    To demonstrate how TiVi maps spatial and temporal variations in normal skin RBCconc at the dorsal side of the hand at rest and during post-occlusive hyperemia.

    Short-term and day-to-day variations in skin RBCconc were quantified at the dorsal side of the hand in four healthy volunteers at rest. In a separate study, the increase in skin RBCconc was recorded during post-occlusive hyperemia.

    A lower skin RBCconc (179-184 TiVi units) was observed at the back of the hand and base of the thumb compared with areas adjacent to the nailfoldfold region of the fingers (190-213 TiVi units). The short-term variation (within 70 s) was < 2% in all areas of the dorsal side of the hand, while day-to-day variations were in the range 5-7% in the back of the hand and up to 10% in areas adjacent to the nailfold region. In the post-occlusive hyperemia phase, up to a 60% increase in skin RBCconc was observed in the early part of the reactive hyperemia phase. This increase in skin RBCconc successively decreased but remained about 18% above the pre-occlusion level after 30 min.

    Establishment of healthy skin RBCconc reference values is important for the design of versatile test procedures for assessment of skin damage caused by vibration tools, chemical exposure or peripheral vascular disease.

  • 29.
    Zhong, Jicun
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Asker, Claes
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Salerud, Göran
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Imaging, image processing and pattern analysis of skin capillary ensembles2000In: Skin research and technology, ISSN 0909-752X, E-ISSN 1600-0846, Vol. 6, no 2, p. 45-57Article in journal (Refereed)
    Abstract [en]

    Background/aims: The capillary bed is recognized as the site where metabolic and nutrient processes occur for living tissues at all levels. The evaluation of this vital process is a major concern in microcirculation. Unlike traditional approaches that concentrated on the extreme local properties of this process, a more global analysis toward capillary ensembles is employed here, since capillaries work as a cooperative entirety. As a first step toward ensemble analysis, the static and planar geometric parameters are investigated. Parameters such as the capillary adjacency and size information are very important in predicting and analysing certain malfunctions in the microvascular bed.

    Methods/results: In order to achieve an objective and accurate analysis of these vital parameters, a computerized imaging system is proposed. Not only the number of capillaries and the capillary cross-sectional areas are important in describing the microvascular bed but the planar distribution pattern of the capillaries also carries valid information. This information, unique to the ensemble analysis, can be used to reveal, visualise and quantify the clustering of capillaries; and this information, according to the Krogh model, is fundamental in estimating the tissue oxygen supply. Two spatial models, the closest neighbor and triangulation methods, have been applied to the captured images of capillary ensembles. The closest neighbor technique generates a minimal distance map or displays a distribution, which depicts the local clustering of capillaries. The triangulation technique, on the other hand, generates a mutual distance map, which is a global description of the capillary positions. Triangulation methods have been evaluated but all except the Greedy triangulation method have been rejected due to lack of robustness and model weakness. Therefore, the capillaries are triangulated by the Greedy triangulation method, and the capillary distribution uniformity is defined as one minus the coefficient of variance of the edge lengths of the mutual distance map.

    Conclusions: A series of advanced image processing methods have been developed that efficiently extract the capillary position, size and distribution information from the images. These results facilitate the automatic counting of capillaries and the capillary size-related pathological analysis.

1 - 29 of 29
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