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  • 1.
    Ahn, Henrik Casimir
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Thoraxkirurgi. Östergötlands Läns Landsting, Hjärtcentrum, Thorax-kärlkliniken.
    Jodal, M.
    Lindhagen, J
    Lundgren, O.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Salerud, Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Bestämning av tunntarmsblodflödet med laser Doppler teknik1984Inngår i: Läkarsällskapets Riksstämma,1984, 1984Konferansepaper (Annet vitenskapelig)
  • 2.
    Ahn, Henrik Casimir
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Thoraxkirurgi. Östergötlands Läns Landsting, Hjärtcentrum, Thorax-kärlkliniken.
    Johansson, K.
    Lindhagen, J.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Salerud, Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Förändringar av blodflödet i ventrikeln i samband med mätt med laser Dopplerteknik1984Inngår i: Läkarsällskapets Riksstämma,1984, 1984Konferansepaper (Annet vitenskapelig)
  • 3.
    Ahn, Henrik Casimir
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Thoraxkirurgi. Östergötlands Läns Landsting, Hjärtcentrum, Thorax-kärlkliniken.
    Lindhagen, J.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Salerud, Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Jodal, M.
    Lundgren, O.
    Evaluation of Laser Doppler Flowmetry in the assessment of blood flow in the small intestine1984Inngår i: Third World Congress of Microcirculation,1984, 1984Konferansepaper (Annet vitenskapelig)
  • 4.
    Ahn, Henrik Casimir
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Thoraxkirurgi. Östergötlands Läns Landsting, Hjärtcentrum, Thorax-kärlkliniken.
    Lindhagen, J
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Salerud, Göran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Jodal, M
    Lundgren, O
    Evaluation of Laser Doppler Flowmetry in the assessment of intestinal blood flow1985Inngår i: Gastroenterology, ISSN 0016-5085, E-ISSN 1528-0012, Vol. 4, nr 88, s. 951-957Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

      

  • 5.
    Arildsson, Mikael
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Strömberg, Tomas
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Effects on skin blood flow by provocation during local analgesia2000Inngår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 59, nr 1, s. 122-130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although topical analgesia cream has been used for several years, little is known about its effects on the microcirculation. Previous studies have shown a vasoconstrictive effect after short application times and a vasodilatation after longer application. It has also been shown that vasomotion does not occur in the analgesized skin. The present study was undertaken to investigate the alterations in skin blood perfusion following local cooling, local heating and pin-pricking after the establishment of analgesia. In 11 healthy volunteers, skin analgesia was attained by use of a eutectic mixture of lidocaine and prilocaine (EMLA, Astra Pain Control AB, Sweden) applied to the skin three hours prior to provocation. The changes in skin blood perfusion, after applying three different provocation methods, were studied using the laser Doppler technique. Local cooling and heating to temperatures of +10 and +45°C, respectively, were applied for 9 s by use of a copper probe (Ø12 mm). In the pin-prick provocation method, a combined effect of deflection and penetration of the skin to in total 3 mm was attained. Identical provocation methods were applied to placebo treated and untreated skin areas. After heat provocation, significant differences in the perfusion response between the treatments were seen (P < 0.0001). Skin areas treated with analgesia cream responded with a slow increase in perfusion that persisted beyond the four minute measurement period. Placebo and untreated areas decreased their perfusion over time. After cooling a significant reduction in skin perfusion was seen, irrespective of the treatment. Similarly, after pin-pricking a perfusion increase was seen for all treatments. The findings indicate that topical analgesia influences the myogenic control of the blood flow in those vascular plexa measured by laser Doppler following heat provocation. No differences could be seen in the response to pin-pricking and cooling for the different treatments.

  • 6.
    Arildsson, Mikael
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Strömberg, Tomas
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry2002Inngår i: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 40, nr 1, s. 85-89Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lassers operating at different wavelengths λ. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with λ is compensated for by a 1/λ effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for λ=632.8nm and 780nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG=123 against 121Hz, finger COG=220 against 212 Hz). When the wavelength changes from 632.8nm to 780nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplifcation increase. For tissues with identical microvascular flow conditions, the output signal therfore tends to increase in magnitude when shifting to longer wavelengths.

  • 7.
    Arildsson, Mikael
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Critical design parameters in laser Doppler perfusion imaging1996Inngår i: Proc. SPIE 2678: Optical Diagnostics of Living Cells and Biofluids / [ed] Daniel L. Farkas; Robert C. Leif; Alexander V. Priezzhev; Toshimitsu Asakura; Bruce J. Tromberg, SPIE Proceedings Series , 1996, Vol. 2678, s. 401-408Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Laser Doppler Perfusion Imaging (LDPI) is a method for visualization of tissue blood perfusion. A low power laser beam is used to step-wise scan a tissue area of interest and a perfusion estimate based on the backscattered, partially Doppler broadened, light is generated. Although the basic operating principle of LDPI is the same as that of conventional Laser Doppler Perfusion Monitoring (LDPM), significant differences exist between the implementation of the methods which must be taken into account in order to generate high quality perfusion images. The purpose of this study is to investigate the relevance of a number of LDPI design parameters, such as:

    (1) The influence of artifact noise when using a continuously moving laser beam instead of a step-wise moving beam to scan the image.

    (2) The signal processor output's dependency on the distance between the measurement object and the scanner head when using collimated laser light.

    (3) The speed and mode of the scanning.

    The results show a substantial rise in the noise level when using a continuously moving beam as opposed to a step-wise. Skin measurements using a collimated laser beam demonstrated an amplification factor dependency on the distance between the skin surface and the scanner head not present when using a divergent laser beam. The scanning speed is limited by the trade-off between the Doppler signal lower cut-off frequency and the image quality.

  • 8.
    Arildsson, Mikael
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Wårdell, Karin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Tracking of small blood vessels by a new laser Doppler imaging technique1996Inngår i: SPIE-Bios96,1996, 1996Konferansepaper (Fagfellevurdert)
  • 9.
    Arildsson, Mikael
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Higher order moment processing of laser Doppler perfusion signals1997Inngår i: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 2, nr 4, s. 358-363Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The laser Doppler technique is used to assess tissue perfusion. Traditionally an integrated, ω-weighted (first-order filter) power spectrum is used to estimate perfusion. In order to be able to obtain selective information about the flow in vessels with different blood cell velocities, higher order filters have been implemented, investigated, and evaluated. Theoretical considerations show that the output of the signal processor will depend on the flow speed, for a given concentration of blood cells, according to Soutνn where v is the average blood cell speed and n is the spectral filter order. An implementation of filters using zero-, first-, second-, and third-order spectral moments was utilized to experimentally verify the theory by using a laser Doppler perfusion imager. Two different flow models were utilized: A Plexiglas model was used to demonstrate the various signatures of the power spectrum for different flow speeds and filter orders, whereas a Delrin model was used to study the relationship between the flow velocity and the output of the signal processor for the different filters. The results show good agreement with theory and also good reproducibility. Recordings made on the skin of the wrist area demonstrated that the flow in small veins can be visualized by the use of higher spectral orders.

  • 10. Clancy, N.
    et al.
    Leahy, MJ.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anderson, Chris
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Non-invasive assessment of the mechanical properties of human skin - investigation of effective age using an optical method2006Inngår i: Royal Academy of Medicine in Ireland, Section of Biomedical Sciences, University of Limerick, Summer Meeting,2006, 2006Konferansepaper (Fagfellevurdert)
  • 11.
    Clancy, Neil T.
    et al.
    Department of Physics, University of Limerick, Ireland.
    Leahy, Martin J.
    Department of Physics, University of Limerick, Ireland.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson, Chris
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Analysis of skin recovery from mechanical indentation using diffuse lighting and digital imaging2007Inngår i: Diffuse Optical Imaging of Tissue / [ed] Brian W. Pogue; Rinaldo Cubeddu, SPIE - International Society for Optical Engineering, 2007, s. 66291G-1-66291G-10Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Skin behaves as a viscoelastic material, having mechanical properties composed of elastic and fluid components. Upon indentation, the fibres are stretched and fluid displaced from the compressed region. The rate of recovery from this imprint is therefore dependent on the hydration and elasticity of the skin. A reliable measurement could be applied to the assessment of clinical conditions such as oedema, rare genetic disorders such as cutis laxa  and the evaluation of the 'effective age' of skin in vivo . This paper describes a new approach to the non-invasive indentation technique and a novel method of analysis. A method is proposed that tracks the skin's recovery optically from an initial strain made using a mechanical indentor, diffuse side-lighting and a CCD video-capture device. Using the blue colour plane of the image it is possible to examine the surface topography only, and track the decay of the imprint over time. Two algorithms are discussed for the extraction of information on the skin's displacement and are analysed in terms of reliability and reproducibility.

  • 12.
    Clancy, Neil T.
    et al.
    Department of Physics, University of Limerick, Ireland.
    Leahy, Martin J.
    Department of Physics, University of Limerick, Ireland.
    Nilsson, Gert E.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson, Chris
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Analysis of skin recovery from mechanical indentation using diffuse lighting and digital imaging. in Diffuse Optical Imaging of Tissue.2007Inngår i: Proceedings of SPIE - Diffuse Optical Imaging of Tissue / [ed] Brian W. Pogue, Rinaldo Cubeddu, Bellingham, WA, United States: SPIE - International Society for Optical Engineering, 2007, s. 66291G-1-66291G-10Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Skin behaves as a viscoelastic material, having mechanical properties composed of elastic and fluid components. Upon indentation, the fibres are stretched and fluid displaced from the compressed region. The rate of recovery from this imprint is therefore dependent on the hydration and elasticity of the skin. A reliable measurement could be applied to the assessment of clinical conditions such as oedema, rare genetic disorders such as cutis laxa and the evaluation of the 'effective age' of skin in vivo . This paper describes a new approach to the non-invasive indentation technique and a novel method of analysis. A method is proposed that tracks the skin's recovery optically from an initial strain made using a mechanical indentor, diffuse side-lighting and a CCD video-capture device. Using the blue colour plane of the image it is possible to examine the surface topography only, and track the decay of the imprint over time. Two algorithms are discussed for the extraction of information on the skin's displacement and are analysed in terms of reliability and reproducibility.

  • 13.
    Clancy, Neil T
    et al.
    University of London Imperial College of Science, Technology and Medicine.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson, Chris
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Dermatologi och venerologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Leahy, Martin J
    University of Limerick.
    A new device for assessing changes in skin viscoelasticity using indentation and optical measurement2010Inngår i: SKIN RESEARCH AND TECHNOLOGY, ISSN 0909-752X, Vol. 16, nr 2, s. 210-228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background/aims Skin is a viscoelastic material, comprised of fluidic and fibrous components. Changes in viscoelasticity can arise due to a number of conditions including dehydration, swelling (associated with injury or disease), impaired heart function, rehydration therapy, ageing, scarring, sun exposure and genetic conditions affecting connective tissue. Quantification of changes in skin viscoelasticity due to these processes is of great clinical interest in the fields of therapy monitoring, wound healing and disease screening. However, devices currently available to measure aspects of the mechanical properties of skin have limitations in ease-of-use, accessibility, and depth of measurement. This paper describes a new technique to follow changes in the viscoelasticity of the skin, using a novel approach to an indentation manoeuvre. The device is portable, low-cost and easy to use while at the same time providing rich information on the mechanical response of the skin. Methods The method proposed optically tracks the skins recovery from an initial strain, made with a novel linear indentor, using diffuse side-lighting and a CCD video camera. Upon indentation, the skins elastin fibres are stretched and fluid is displaced from the compressed region. When the indentor is removed, the rate of recovery of the skin from this imprint is therefore principally dependent on its hydration and elasticity. Using the blue colour plane of the image and polarisation filtering, it is possible to examine the surface topography only, and track the decay of the imprint over time. Results The decrease in size of the imprint over time (decay curve) recorded by the device is shown to agree with the theoretical predictions of an appropriate viscoelastic model of skin mechanical behaviour. The contributors to the response measured using the indentation device are fully characterised and evaluated using separate measurement techniques including high-frequency ultrasound, polarisation spectroscopy and optical coherence tomography. Conclusion The device developed is capable of tracking the viscoelastic response of skin to minimal indentation. The high precision achieved using low-cost materials means that the device could be a viable alternative to current technologies.

  • 14. Clancy, NT.
    et al.
    Leahy, MJ.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Non-invasive assessment of the mechanical properties of human skin - investigation of effective age using an optical method2006Inngår i: BioMed 2006,2006, 2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

      

  • 15. Clancy, NT.
    et al.
    Leahy, MJ.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anderson, Chris
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Analysis of mechanical imprints in human skin using an optical technique. in Fission Impossible?2007Inngår i: IOPI Spring Weekend Meeting,2007, 2007Konferansepaper (Fagfellevurdert)
  • 16.
    Droog Tesselaar, Erik
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Henricson, Joakim
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert E.
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Brännskadevård. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    A protocol for iontophoresis of acetylcholine and sodium nitroprusside that minimises nonspecific vasodilatory effects2004Inngår i: Microvascular research, ISSN 0026-2862, Vol. 67, nr 2, s. 197-202Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Iontophoresis of vasoactive substances is a promising tool for studying pharmacological aspects of the (patho)physiology of the microvasculature. However, nonspecific microvascular responses are a common problem in most protocols used. We studied the effect of current density (mA/cm2), charge density (mC/cm2), drug concentration (mass %) and vehicle concentration (M) on the nonspecific vasodilatation during iontophoresis of sodium chloride, acetylcholine (ACh) and sodium nitroprusside (SNP).

    We found that nonspecific vasodilatation depended on current density and charge density in both anodal and cathodal iontophoresis. The responses to ACh and SNP were dependent on current density, charge density and drug concentration. We found that by limiting current density (<0.01 mA/cm2) and charge density (<7.8 mC/cm2) and with adjusted concentrations for drugs and vehicles, it is possible to prevent nonspecific effects during iontophoresis of ACh and SNP, while maximum drug effects (plateaus in the dose–response curves) are still obtained. These new findings are important for future iontophoresis studies in which vasoactive drugs are used to assess microvascular function because the presented approach has advantages compared to older techniques, which mainly have attempted to suppress or compensate for the nonspecific responses during iontophoresis by the use of local anaesthetics or the measurement of drug-minus-vehicle responses, both of which present well-known experimental shortcomings.

  • 17.
    Fullerton, A.
    et al.
    Leo Pharmaceutical Products Ltd.
    Stücker, M.
    Ruhr Universitet Bochum.
    Wilhelm, K-P.
    proDERM Institute for Applied Derm. Res. GmbH.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson, C.
    Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Hudkliniken i Östergötland.
    Fisher, T.
    National Institute of Working Life, Solna.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Serup, J.
    Leo Pharmaceutical Products Ltd.
    Guidelines for visualisation of cutaneous blood flow by laser Doppler imaging2002Inngår i: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 46, nr 3, s. 129-140Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This report reviews how to set up a laser Doppler perfusion imaging system intended for visualization of skin blood perfusion, capture images and evaluate the results obtained. A brief summary of related papers published in the literature within the areas of skin irritant and allergy patch testing, microdialysis and skin tumour circulation is presented, as well as early applications within other fields such as diabetology, wound healing and microvascular research.

  • 18.
    Golster, Helena
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Anestesiologi med intensivvård. Linköpings universitet, Institutionen för biomedicin och kirurgi, Hand och plastikkirurgi. Linköpings universitet, Hälsouniversitetet.
    Lindén, Maria
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Bertuglia, Silvia
    CNR Institute of Clinical Physiology, Pisa, Italy.
    Calantuoni, Antonio
    CNR Institute of Clinical Physiology, Pisa, Italy.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för medicin och hälsa, Anestesiologi med intensivvård. Linköpings universitet, Institutionen för biomedicin och kirurgi, Hand och plastikkirurgi. Linköpings universitet, Hälsouniversitetet.
    Red Blood Cell Velocity and Volumetric Flow Assessment by Enhanced High-Resolution Laser Doppler Imaging in Separate Vessels of the Hamster Cheek Pouch Microcirculation1999Inngår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 58, nr 1, s. 62-73Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An enhanced high-resolution laser Doppler imager (EHR-LDI), configured to fit the demands of a measurement area containing separate microvessels, was evaluated for perfusion measurements in hamster cheek pouch preparations during ischemia, reperfusion, and pharmacologically induced vasodilation and vasoconstriction. Measurements in separate microvessels where the laser beam was smaller than the vessel diameter were referred to as red blood cell (RBC) velocity estimates, as previously validated in vitro, whereas a relative flow index, RFI (mean RBC velocity/tissue area), was introduced as a volumetric flow measure. Microvessel diameter and RBC velocity changes during ischemia, reperfusion, as well as during vasoconstriction and vasodilation correlated to the data obtained from the microscope. Correspondingly, during the described provocations anticipated volumetric flow changes were registered as changes in the RFI. When data on intravessel RBC velocity profiles are presented they reflect a parabolic flow profile usually seen in this size microvessel. The EHR-LDI appears a promising tool for investigation of the microvasculature, as it almost simultaneously provides information on relative changes of both in vivo RBC velocity and volumetric flow (RFI), although the latter estimate needs to be further refined.

  • 19. Gustavsson, U.
    et al.
    Wårdell, Karin
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Lewis, D.H.
    Vasomotion in rat skeletal muscle induced by hemorrhage as recorded by laser Doppler flowmetry1991Inngår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, nr 42, s. 224-228Artikkel i tidsskrift (Fagfellevurdert)
  • 20.
    Henricson, Joakim
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Droog Tesselaar, Erik
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Baiat, Y
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Brännskadevård. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken med brännskadeenheten.
    Assessment of microvascular response to iontophoresis ofnoradrenaline and phenylephrine using local heating andlaser Doppler flowmetryManuskript (Annet vitenskapelig)
    Abstract [en]

    Laser-Doppler flowmetry (LDF) is an attractive method to assess blood flow responses butlacks sensitivity to accurately measure low perfusion values during iontophoresis of vasoconstricting drugs without predilatation of the microvascular bed.

    The aim of this study was to develop a protocol for iontophoresis of noradrenaline (NA) andphenylephrine (Phe) in the skin, using local heating to predilate the microvascular bed andLDF to measure blood flow responses. Three protocols with the same electrical charge (12mC) but different durations and current strengths (100 s x 0.12 mA, 200 s x 0.06 mA, 300 s x0.04 mA) were used to study the effect of pulse duration and current strength on the responses.

    Skin perfusion decreased to 68-78% of the predilatated state with both NA and Phe. Doseresponse plateaus were not obtained with any protocol. The extent of the vasoconstriction depended on the protocol used.

    These results suggest that predilatation by local heating appears less suitable duringiontophoresis of NA and Phe, due to limited vascular responses and especially absence of response plateaus, even at high current strengths. The latter leads to difficulties in performing proper dose response analyses. Another interesting finding was that the actual dose of NA and Phe given to the tissue was affected not only by the size of the electrical charge, but local blood flow as well.

  • 21.
    Henricson, Joakim
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Droog Tesselaar, Erik
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Tekniska högskolan.
    Persson, Karin
    Linköpings universitet, Institutionen för medicin och hälsa, Farmakologi. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Brännskadevård. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Assessment of microvascular function by study of the dose‐response effects of iontophoretically applied drugs (acetylcholine and sodium nitroprusside): Methods and comparison with in vitro studies2007Inngår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 73, nr 2, s. 143-149Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Current knowledge about vascular function stems mainly from pharmacological in vitro studies using mounted vascular strips on a strain gauge. We know of no paper that has systematically examined the possibility of assessing the conventional dose–response effects of iontophoresis and laser Doppler investigation of vasoactive substances and compared those relations to data obtained from strips mounted on a strain gauge.

    We used the vasoactive substances acetylcholine (endothelium dependent) and sodium nitroprusside (endothelium independent) and an antagonist (atropine) to enable further investigations in the receptor physiology of iontophoresis.

    Dose–response curves from the iontophoresis experiments showed close similarity to those obtained by vascular strips mounted on a strain gauge. The coefficient of variation (CV) of the dose–response factors found in iontophoresis (both inter and intra experimental variability) was low. The iontophoretic effective dose of 50% (ED50) for acetylcholine and nitroprusside had only CVs of 25% and 26%, respectively, compared with 71% and 77% for the vascular strips. Acetylcholine-induced response was antagonized by iontophoresis of atropine. Contrary to expectations, this antagonism was not competitive.

    The results show that iontophoresis in combination with laser Doppler technology produces reproducible and reliable dose–response curves that picture the vascular effects of vasoactive drugs.

  • 22.
    Henricson, Joakim
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi.
    Nilsson, A.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Sjöberg, Folke
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Sub-epidermal imaging using polarized light spectroscopy for assessment of cutaneous microvascular function during iontophoresis of nor-adrenaline and phenylephrine2007Inngår i: 8th World Congress for microcirculation,2007, 2007Konferansepaper (Fagfellevurdert)
  • 23.
    Henricson, Joakim
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Anders
    Berzelius Clinical Research Center AB.
    Tesselaar, Erik
    Berzelius Clinical Research Center AB.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Brännskadevård. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Tissue viability imaging: Microvascular response to vasoactive drugs induced by iontophoresis2009Inngår i: Microvascular Research, ISSN 0026-2862, Vol. 78, nr 2, s. 199-205Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When one is studying the physiology of the cutaneous microcirculation there is a need for relevant non-invasive and versatile techniques. In this study we used a new optical device, the tissue viability imager (TiVi), to map changes in cutaneous microvascular concentrations of red blood cells during iontophoresis of vasoactive substances (noradrenaline (NA) and phenylephrine (Phe) for vasoconstriction and acetylcholine (ACh) and sodium nitroprusside (SNP) for vasodilatation). We aimed to present data both individually and pooled, using a four-variable logistic dose response model that is commonly used in similar in vitro vascular studies. The accuracy of the TiVi was also investigated by calculating the coefficient of variation and comparing it with similar tests previously done using laser Doppler imaging.

    Tests were also performed using the TiVi and LDPI simultaneously to further compare the two methods. Results showed that the TiVi is capable of quantifying vascular responses to iontophorised noradrenaline and phenylephrine without the need to increase background flow first. Fitting the TiVi data to the dose response model resulted in ED50-values with narrow confidence intervals and acceptable r2 values. Mean ED50-values for the TiVi did not differ significantly from similar values obtained using laser Doppler.

    Results further seem to suggest that when the blood perfusion increases during vasodilatation in skin the initial phase relies mainly on an increase in red blood cell concentration whereas the further perfusion increase is due to an increase in red blood cell velocity.

  • 24.
    Henricson, Joakim
    et al.
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Sjöberg, Folke
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Microvascular response to iontophoretically applied acetylcholine investigated by Tissue Viability Imaging2006Konferansepaper (Annet vitenskapelig)
  • 25.
    Henricson, Joakim
    et al.
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Sjöberg, Folke
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Anderson, Chris
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    The polarization scectroscopic camera allows assessment of vasoconstriction after topical application of clobetasol2007Inngår i: 16th congress of the European Academy of Dermatology and Venerology,2007, 2007Konferansepaper (Fagfellevurdert)
  • 26. Leahy, M.
    et al.
    ODoherty, J.
    Henricson, Joakim
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi.
    Sjöberg, Folke
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Tissue Viability Imaging: A new modality for microcirculation imaging2006Inngår i: Imaging Technology in Drug Discovery Development,2006, 2006Konferansepaper (Fagfellevurdert)
  • 27.
    Leahy, Martin J.
    et al.
    Department of Physics, University of Limerick Limerick, Ireland.
    O'Doherty, Jim
    Department of Physics, University of Limerick Limerick, Ireland.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Henricson, Joakim
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Linköpings universitet, Tekniska högskolan.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    Anderson, Chris
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Dermatologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken US.
    A new method for visualizing red blood cell content in the microcirculation2007Inngår i: Progress in Biomedical Optics and Imaging, ISSN 1605-7422, E-ISSN 1042-4687Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    n/a

  • 28.
    Leahy, M.J.
    et al.
    University of Oxford.
    de Mul, F.F.M.
    University of Twente.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Maniewski, R.
    Polish Academy of Sciences.
    Developments in laser Doppler blood perfusion monitoring2002Inngår i: SPIE Conference,2002, 2002Konferansepaper (Fagfellevurdert)
  • 29.
    Leahy, M.J.
    et al.
    University of Oxford .
    de Mul, F.F.M.
    University of Twente Enschede, NL.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Maniewski, R
    Polish Academy of Sciences Warsaw.
    Principles and practice of the laser-Doppler perfusion technique1999Inngår i: Technology and Health Care, ISSN 0928-7329, Vol. 7, s. 143-162Artikkel i tidsskrift (Fagfellevurdert)
  • 30.
    Leahy, M.J.
    et al.
    Biophotonics Laboratory, OFSRC, Department of Physics, Limerick, Ireland.
    Enfield, J.G.
    Biophotonics Laboratory, OFSRC, Department of Physics, Limerick, Ireland.
    Clancy, N.T.
    Biophotonics Laboratory, OFSRC, Department of Physics, Limerick, Ireland.
    O'Doherty, J.
    Biophotonics Laboratory, OFSRC, Department of Physics, Limerick, Ireland.
    McNamara, P.
    Biophotonics Laboratory, OFSRC, Department of Physics, Limerick, Ireland.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Biophotonic methods in microcirculation imaging2007Inngår i: Medical Laser Application, ISSN 1615-1615, E-ISSN 1878-3228, Vol. 22, nr 2, s. 105-126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Visible and near-infrared light, particularly in the wavelength region of 600-1100 nm, offer a window into human and animal tissues due to reduced scattering and absorption. We review the main biophotonic methods applied to visualisation and assessment of the microcirculation and document the progress made over the past 10 years in particular. Applications, particularly in human skin, are of special topical importance due to an improved knowledge of its role and its value as a surrogate for other organs in drug testing at a time when drug development is under severe pressure. © 2007.

  • 31.
    Leahy, MJ.
    et al.
    Department of Physics, University of Limerick, National Technological Park, Ireland.
    ODoherty, J.
    Department of Physics, University of Limerick, National Technological Park, Ireland.
    McNamara, P.
    Department of Physics, University of Limerick, National Technological Park, Ireland.
    Henricson, Joakim
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Diffuse reflection imaging of sub-epidermal tissue haematocrit using a simple RGB camera2007Inngår i: Optical Technologies in Biophysics and Medicine VIII / [ed] Valery V. Tuchin, SPIE - International Society for Optical Engineering, 2007, Vol. 6535, s. 653503-1-653503-17Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper describes the design and evaluation of a novel easy to use, tissue viability imaging system (TiVi). The system is based on the methods of diffuse reflectance spectroscopy and polarization spectroscopy. The technique has been developed as an alternative to current imaging technology in the area of microcirculation imaging, most notably optical coherence tomography (OCT) and laser Doppler perfusion imaging (LDPI). The system is based on standard digital camera technology, and is sensitive to red blood cells (RBCs) in the microcirculation. Lack of clinical acceptance of both OCT and LDPI fuels the need for an objective, simple, reproducible and portable imaging method that can provide accurate measurements related to stimulus vasoactivity in the microvasculature. The limitations of these technologies are discussed in this paper. Uses of the Tissue Viability system include skin care products, drug development, and assessment spatial and temporal aspects of vasodilation (erythema) and vasoconstriction (blanching).

  • 32. Leahy, MJ.
    et al.
    ODoherty, J.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Henricson, Joakim
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi.
    Sjöberg, Folke
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för kirurgi. Östergötlands Läns Landsting, Rekonstruktionscentrum, Hand- och plastikkirurgiska kliniken US.
    A new method for visualizing red blood cell content in the microcirculation. SPIE newsroom2006Inngår i: The International Society for Optical Engineering,2006, 2006Konferansepaper (Fagfellevurdert)
  • 33. Liebert, A.
    et al.
    Terajewicz, N.
    Maniewski, R.
    Polish Academy of Sciences.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    deMul, F.F.M.
    Estimation of scattering volume in short distance reflectance measurements by Monte Carlo modelling2003Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The depth of light penetration is an interesting issue in various tissue optics experiments. The measurements of remitted light distribution was shown to allow for estimation of optical properties. However, in case of measurements with a short distance between the emitter and the detector, the diffusion equation fails, and the proposed methods cannot be applied. The aim of this study was to develop a simple method for estimation of the light penetration depth for short-distance measurements of remitted light. The idea is based on the analysis of the diffusely back-scattered light distribution adjacent to the emitter for the assessment of the scattering volume. The Monte Carlo method was used for theoretical estimation of the relationship between the light distribution around emitting fiber and the depth of light scattering volume. Two series of Monte Carlo simulations were performed: the first one with limited and the second one with unlimited scattering volume. In both series the values of absorption and scattering coefficients were altered within ranges typical of human tissues. The results of this study show that: the diffuse reflectance is strongly dependent on the absorption and scattering properties of the tissue and it is possible to estimate the depth of the scattering volume by use of the short distance profile of diffusely back-scattered light as measured at the surface of the tissue.

  • 34.
    Lindén, Maria
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Golster, Helena
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Hand och plastikkirurgi. Linköpings universitet, Institutionen för medicin och hälsa, Anestesiologi med intensivvård. Linköpings universitet, Hälsouniversitetet.
    Bertuglia, Silvia
    CNR Institute of Clinical Physiology, Via Trieste, Pisa, Italy.
    Colantuoni, Antonio
    CNR Institute of Clinical Physiology, Via Trieste, Pisa, Italy.
    Sjöberg, Folke
    Linköpings universitet, Institutionen för biomedicin och kirurgi, Hand och plastikkirurgi. Linköpings universitet, Institutionen för medicin och hälsa, Anestesiologi med intensivvård. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik. Linköpings universitet, Hälsouniversitetet.
    Evaluation of Enhanced High-Resolution Laser Doppler Imaging in an in Vitro Tube Model with the Aim of Assessing Blood Flow in Separate Microvessels1998Inngår i: Microvascular Research, ISSN 0026-2862, E-ISSN 1095-9319, Vol. 56, nr 3, s. 261-270Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An enhanced high-resolution laser Doppler imaging (EHR-LDI) technique intended for visualization of separate microvessels was evaluated by use ofin vitroflow models. In EHR-LDI, a laser beam focused to a half-power diameter less than 40 μm successively scans the tissue under study in steps of 25 μm. Spatial blood flow variations within microvascular structures of 1.5 × 1.5 mm are rendered by 64 × 64 measurement sites. Individual microvessel diameters could be estimated and an average difference of 11 μm compared to microscopic measurements was obtained. For the flow algorithm used, the LDI output signal was found to scale linearly with average velocity (0–3.5 mm/s) when a plastic tube of inner diameter 175 μm was perfused with human blood (correlation coefficient 0.99). The LDI output signal was further found insensitive to hematocrit variations in the range 16–44%. Due to the limited laser light penetration in blood, a reduction in the LDI output signal was observed as the inner tube diameters were successively changed from 280 to 1400 μm.

  • 35.
    Lindén, Maria
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Sirsjö, A
    Lindbom, L
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Gidlöf, A
    Laser Doppler perfusion imaging of microvascular blood flow in rabbit tenuissimus muscle1995Inngår i: American journal of physiology, ISSN 0002-9513, Vol. 269, s. 1496-1500Artikkel i tidsskrift (Fagfellevurdert)
  • 36.
    Litscher, G.
    et al.
    University of Graz, Austria.
    Wang, L.
    University of Graz, Austria.
    Huber, E.
    University of Graz, Austria.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Changed skin blood perfusion in the fingertip following acupuncture needle introduction as evaluated by Laser Doppler Perfusion Imaging2002Inngår i: Lasers in Medical Science, ISSN 0268-8921, E-ISSN 1435-604X, Vol. 17, nr 1, s. 19-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rapidly repeated imaging of the left middle fingertip skin blood perfusion was performed in 51 healthy volunteers (mean age ▒ SD: 25.3 ▒ 7.6 years) prior to, immediately after and in the early reperfusion phase following introduction of an acupuncture needle at the Neiguan point (Pe. 6) and at a placebo point respectively, using a Laser Doppler Perfusion Imager (LDPI). The average skin perfusion of the fingertip was calculated for each image and used as an indicator of the microvascular response to the acupuncture needle introduction. The results of this randomised, placebo-controlled, cross-over study showed significant differences (p = 0.001) in the immediate skin blood perfusion response when needling is performed in an acupuncture point (Neiguan) and a placebo point, with a more pronounced reduction in skin blood perfusion when needling the acupuncture point. In the early reperfusion phase, however, a substantial increase in skin perfusion was observed that amounted to about 18% of the level prior to needle introduction, irrespective of the site of needle application. In a single individual it was demonstrated that the vasodilatation following needling in the acupuncture point persisted for a more extended time period. These results suggest that the LDPI technology may be useful in visualising and quantifying the peripheral vascular effects of acupuncture on the microcirculation.

  • 37.
    Magnusson, B.M.
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Dermatologi och venerologi. Linköpings universitet, Hälsouniversitetet.
    Henricson, Joakim
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Anderson, Chris
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Dermatologi och venerologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Intra- and inter-individual variability in the development of erythema after application of methyl nicotinate evaluated by polarization spectroscopy imaging2010Inngår i: JOURNAL OF PHARMACY AND PHARMACOLOGY, vol 62, issue 6, pp 801-801, ISSN: 002-3573, Pharmaceutical Press , 2010, Vol. 62, nr 6, s. 801-801Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The concept that the time to onset of erythema after the application of the rubefacient and urticant substance methyl nicotinate (MN) indicates skin barrier competence was introduced 30 years ago. MN produces a dose-dependent erythema on topical application to intact skin, the nature of which is known to be fast moving (in the order of minutes) and variable. Using tissue viability imaging (TiVi) the time course and degree of the reaction can be conveniently followed and analysed. Inter-individual variability can be quite marked but intra-individual variability is less pronounced. At the upper end of provocation (higher doses, more sensitive individuals) urtication can occur, which decreases blood flow by increasing pressure on and thus emptying capillaries. The TiVi system can quantitate urtication and inherent (blanched) skin colour. The utility of MN application in the study of individual barrier function and microvascular reactivity is increased by the use of the TiVi system for collection and analysis of data.

  • 38. Magnusson, BM.
    et al.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Anderson, Chris
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    The polarization spectroscopy camera - a promising tool for assessment of erythemateous reactions to topically applied agents2006Inngår i: La Grande Motte,2006, 2006Konferansepaper (Fagfellevurdert)
  • 39. McNamara, P.
    et al.
    ODoherty, J.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Leahy, MJ.
    Monte Carlo modelling of light propagation in human skin2006Inngår i: Royal Academy of Medicine in Ireland, Section of Biomedical Sciences, Summer Meeting, University of Limerick,2006, 2006Konferansepaper (Fagfellevurdert)
  • 40.
    McNamara, Paul N
    et al.
    University of Limerick, Ireland.
    O'Doherty, Jim
    Royal Surrey County Hospital, Guildford, UK.
    O'Connell, Marie-Louise
    University of Limerick.
    Fitzgerald, Barry W
    University of Limerick, Ireland.
    Anderson, Chris
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Dermatologi och venerologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken i Östergötland.
    Nilsson, Gert
    Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
    Toll, Rani
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Närsjukvården i centrala Östergötland, Akutkliniken.
    Leahy, Martin J
    University of Limerick, Ireland.
    Tissue viability (TiVi) imaging: temporal effects of local occlusion studies in the volar forearm2010Inngår i: Journal of Biophotonics, ISSN 1864-063X, E-ISSN 1864-0648, Vol. 3, nr 1-2, s. 66-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tissue Viability (TiVi) imaging is a promising new technology for the assessment of microcirculation in the upper human dermis. Although the technique is easily implemented and develops large amounts of observational data, its role in the clinical workplace awaits the development of standardised protocols required for routine clinical practice. The present study investigates the use of TiVi technology in a human, in vivo, localized, skin blood flow occlusion protocol. In this feasibility study, the response of the cutaneous microcirculation after provocation on the volar surface of the forearm was evaluated using a high temporal-low spatial resolution TiVi camera. 19 healthy subjects - 10 female and 9 male - were studied after a localized pressure was applied for 5 different time periods ranging from 5 to 25 seconds. Areas corresponding to 100 x 100 pixels (2.89 cm(2)) were monitored for 60 seconds prior to, during and after each occlusion period. Our results demonstrated the removal of blood from the local area and a hyperaemic response supporting the suitability of TiVi imaging for the generation of detailed provocation response data of relevance for the physiological function of the skin microcirculation in health and disease.

  • 41. Möller, K.O
    et al.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Fagrell, B
    Introduction to Laser Doppler Flowmetry1999Inngår i: Technology and Health Care, ISSN 0928-7329, E-ISSN 1878-7401, ISSN 0928-7329, Vol. 7Artikkel i tidsskrift (Fagfellevurdert)
  • 42.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    4. New Possibilities for skin imager (interview with G Nilsson), Sweden Today, No 12007Annet (Annet (populærvitenskap, debatt, mm))
  • 43.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Bringing Bioengineering Innovations to the Market2008Annet (Annet (populærvitenskap, debatt, mm))
  • 44.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    DERMATECH 2010 - Bildanalys inomdermatology. Visioner för medicinsk bildanalys i Östergötland2007Annet (Annet (populærvitenskap, debatt, mm))
  • 45.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Från medicinska behov och tekniska idéer till medicintekniska innovationer och företagsbildning2008Inngår i: Medicinteknikdagarna 2008,2008, 2008Konferansepaper (Fagfellevurdert)
    Abstract [sv]

       

  • 46.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Föreläsningsturné, Frankrike (i samarbete med exporrådet Frankrike), 24-29 juni 20072007Annet (Annet (populærvitenskap, debatt, mm))
  • 47.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    High resolution2000Rapport (Annet vitenskapelig)
  • 48.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    History of laser Doppler technology2000Inngår i: European Conference on Microcirculation,2000, 2000Konferansepaper (Fagfellevurdert)
  • 49.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Laser Doppler and spectroscopy techniques in skin microcirculation assessment2007Annet (Annet (populærvitenskap, debatt, mm))
  • 50.
    Nilsson, Gert
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik.
    Laser Doppler imagingstudies of tissue perfusion1998Inngår i: Advances inOptical Imaging and Photon Migration TOpical Meeting,1998, 1998Konferansepaper (Annet vitenskapelig)
123 1 - 50 of 118
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