The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Ole Bang - One of the best experts on this subject based on the ideXlab platform.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
Biomedical Optics Express, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised of the lower surface of a single cell layer in epidermis (the stratum basale) connected to an even thinner membrane (the basement membrane). The basement membrane is attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system (Vivosight from Michaelson Diagnostics) and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. To our knowledge no detailed delineating of the DEJ in the UHR-OCT image has previously been reported, despite many publications within this field. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20 μm, and in imaging the dermal papillae where, when utilising the UHR-OCT, capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
arXiv: Medical Physics, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised by the lower surface of a single cell layer in epidermis connected to an even thinner basement membrane, attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20mm, and in imaging the dermal papillae where capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
Niels Moller Israelsen - One of the best experts on this subject based on the ideXlab platform.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
Biomedical Optics Express, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised of the lower surface of a single cell layer in epidermis (the stratum basale) connected to an even thinner membrane (the basement membrane). The basement membrane is attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system (Vivosight from Michaelson Diagnostics) and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. To our knowledge no detailed delineating of the DEJ in the UHR-OCT image has previously been reported, despite many publications within this field. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20 μm, and in imaging the dermal papillae where, when utilising the UHR-OCT, capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
arXiv: Medical Physics, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised by the lower surface of a single cell layer in epidermis connected to an even thinner basement membrane, attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20mm, and in imaging the dermal papillae where capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
Josep Valls-solé - One of the best experts on this subject based on the ideXlab platform.
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The effects of transcranial direct current stimulation on conscious perception of sensory inputs from Hand Palm and dorsum
The European journal of neuroscience, 2014Co-Authors: A. Westgeest, Merche Morales, Christopher Cabib, Josep Valls-soléAbstract:Conscious perception of sensory signals depends in part on stimulus salience, relevance and topography. Letting aside differences at skin receptor level and afferent fibres, it is the CNS that makes a contextual selection of relevant sensory inputs. We hypothesized that subjective awareness (AW) of the time at which a sensory stimulus is perceived, a cortical function, may be differently modified by cortical stimulation, according to site and type of the stimulus. In 24 healthy volunteers, we examined the effects of transcranial direct current stimulation (tDCS) on the assessment of AW to heat pain or weak electrical stimuli applied to either the Hand Palm or dorsum. We also recorded the vertex-evoked potentials to the same stimuli. The assessment was done before, during and after cathodal or anodal tDCS over the parietal cortex contralateral to the Hand receiving the stimuli. At baseline, AW to thermal stimuli was significantly longer for Palm than for dorsum (P
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P 30. The effects of transcranial direct current stimulation on conscious perception of sensory inputs from Hand Palm and dorsum
Clinical Neurophysiology, 2013Co-Authors: A. Westgeest, Josep Valls-solé, Merche Morales, S. Rudilosso, A. RenuAbstract:Introduction Conscious perception of sensory inputs is dependent on the salience and relevance given to them. As a consequence, there can be differences in subjective awareness (AW) of the timing of sensory perception according to site and type of the stimulus. Since this is a cortical function, it might be susceptible to modification through brain stimulation. Objectives To characterize differences in AW and investigate the effects of transcranial direct current stimulation (tDCS) on the conscious perception of sensory inputs from glabrous and hairy skin. Materials and methods In 14 healthy volunteers, we applied heat pain and weak electrical stimuli to the Hand Palm and dorsum while subjects were assessing the time of sensory perception through the Libet’s clock (Libet et al., Brain 1983;106:623–42). In brief, subjects were requested to state the position of the clock’s Hand at the time they felt the stimulus. Latency of AW was calculated as the difference between the actual time at which the stimulus was issued and its subjective assessment. In order to assess whether the cortex’s role in processing sensory inputs differs for stimulus site and type, we examined the effects on AW of cathodal (inhibitory) tDCS over the parietal cortex contralateral to the Hand receiving thermal and electrical stimuli. Results Latency of AW was significantly longer for thermal than for electrical stimuli, in correspondence with the different conduction velocity of the axons involved. It was also longer for Palm than for dorsum for thermal stimulation ( p Conclusion Longer latency of AW in the Palm than in the dorsum is attributable to the thickness of the skin in the Hand Palm, which leads to a deeper location of the receptors. These differences are not seen with electrical stimuli because they activate directly the subcutaneous myelinated axons. The finding that tDCS caused a change in latency of AW exclusively to thermal stimulation of the glabrous skin indicates a cortical control of nociceptive inputs that is specific for Hand Palm and could be related to the need to hold potentially harmful objects.
A. Westgeest - One of the best experts on this subject based on the ideXlab platform.
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The effects of transcranial direct current stimulation on conscious perception of sensory inputs from Hand Palm and dorsum
The European journal of neuroscience, 2014Co-Authors: A. Westgeest, Merche Morales, Christopher Cabib, Josep Valls-soléAbstract:Conscious perception of sensory signals depends in part on stimulus salience, relevance and topography. Letting aside differences at skin receptor level and afferent fibres, it is the CNS that makes a contextual selection of relevant sensory inputs. We hypothesized that subjective awareness (AW) of the time at which a sensory stimulus is perceived, a cortical function, may be differently modified by cortical stimulation, according to site and type of the stimulus. In 24 healthy volunteers, we examined the effects of transcranial direct current stimulation (tDCS) on the assessment of AW to heat pain or weak electrical stimuli applied to either the Hand Palm or dorsum. We also recorded the vertex-evoked potentials to the same stimuli. The assessment was done before, during and after cathodal or anodal tDCS over the parietal cortex contralateral to the Hand receiving the stimuli. At baseline, AW to thermal stimuli was significantly longer for Palm than for dorsum (P
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P 30. The effects of transcranial direct current stimulation on conscious perception of sensory inputs from Hand Palm and dorsum
Clinical Neurophysiology, 2013Co-Authors: A. Westgeest, Josep Valls-solé, Merche Morales, S. Rudilosso, A. RenuAbstract:Introduction Conscious perception of sensory inputs is dependent on the salience and relevance given to them. As a consequence, there can be differences in subjective awareness (AW) of the timing of sensory perception according to site and type of the stimulus. Since this is a cortical function, it might be susceptible to modification through brain stimulation. Objectives To characterize differences in AW and investigate the effects of transcranial direct current stimulation (tDCS) on the conscious perception of sensory inputs from glabrous and hairy skin. Materials and methods In 14 healthy volunteers, we applied heat pain and weak electrical stimuli to the Hand Palm and dorsum while subjects were assessing the time of sensory perception through the Libet’s clock (Libet et al., Brain 1983;106:623–42). In brief, subjects were requested to state the position of the clock’s Hand at the time they felt the stimulus. Latency of AW was calculated as the difference between the actual time at which the stimulus was issued and its subjective assessment. In order to assess whether the cortex’s role in processing sensory inputs differs for stimulus site and type, we examined the effects on AW of cathodal (inhibitory) tDCS over the parietal cortex contralateral to the Hand receiving thermal and electrical stimuli. Results Latency of AW was significantly longer for thermal than for electrical stimuli, in correspondence with the different conduction velocity of the axons involved. It was also longer for Palm than for dorsum for thermal stimulation ( p Conclusion Longer latency of AW in the Palm than in the dorsum is attributable to the thickness of the skin in the Hand Palm, which leads to a deeper location of the receptors. These differences are not seen with electrical stimuli because they activate directly the subcutaneous myelinated axons. The finding that tDCS caused a change in latency of AW exclusively to thermal stimulation of the glabrous skin indicates a cortical control of nociceptive inputs that is specific for Hand Palm and could be related to the need to hold potentially harmful objects.
Adrian Gh. Podoleanu - One of the best experts on this subject based on the ideXlab platform.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
Biomedical Optics Express, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised of the lower surface of a single cell layer in epidermis (the stratum basale) connected to an even thinner membrane (the basement membrane). The basement membrane is attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system (Vivosight from Michaelson Diagnostics) and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. To our knowledge no detailed delineating of the DEJ in the UHR-OCT image has previously been reported, despite many publications within this field. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20 μm, and in imaging the dermal papillae where, when utilising the UHR-OCT, capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
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the value of ultrahigh resolution oct in dermatology delineating the dermo epidermal junction capillaries in the dermal papillae and vellus hairs
arXiv: Medical Physics, 2018Co-Authors: Niels Moller Israelsen, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Adrian Gh. Podoleanu, Michael Maria, Merete Haedersdal, Ole BangAbstract:Optical coherence tomography (OCT) imaging of the skin is gaining recognition and is increasingly applied to dermatological research. A key dermatological parameter inferred from an OCT image is the epidermal (Ep) thickness as a thickened Ep can be an indicator of a skin disease. Agreement in the literature on the signal characters of Ep and the subjacent skin layer, the dermis (D), is evident. Ambiguities of the OCT signal interpretation in the literature is however seen for the transition region between the Ep and D, which from histology is known as the dermo-epidermal junction (DEJ); a distinct junction comprised by the lower surface of a single cell layer in epidermis connected to an even thinner basement membrane, attached to the underlying dermis. In this work we investigate the impact of an improved axial and lateral resolution on the applicability of OCT for imaging of the skin. To this goal, OCT images are compared produced by a commercial OCT system and by an in-house built ultrahigh resolution (UHR-) OCT system for dermatology. In 11 healthy volunteers, we investigate the DEJ signal characteristics. We perform a detailed analysis of the dark (low) signal band clearly seen for UHR-OCT in the DEJ region where we, by using a transition function, find the signal transition of axial sub-resolution character, which can be directly attributed to the exact location of DEJ, both in normal (thin/hairy) and glabrous (thick) skin. For selected healthy volunteers, we investigate the dermal papillae and the vellus hairs and identify distinct features that only UHR-OCT can resolve. Differences are seen in tracing hairs of diameter below 20mm, and in imaging the dermal papillae where capillary structures are identified in the Hand Palm, not previously reported in OCT studies and specifically for glabrous skin not reported in any other in vivo optical imaging studies.
