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Lars O. Svaasand - One of the best experts on this subject based on the ideXlab platform.
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characterization of vascular structures and skin Bruises using hyperspectral imaging image analysis and diffusion theory
Journal of Biophotonics, 2009Co-Authors: Lise Lyngsnes Randeberg, Eivind L P Larsen, Lars O. SvaasandAbstract:Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin Bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400–1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify Bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectra from the images. The results show that hyperspectral images contain depth information, and that the approximate depth and extent of Bruises can be retrieved using a combination of statistical image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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characterization of vascular structures and skin Bruises using hyperspectral imaging image analysis and diffusion theory
Journal of Biophotonics, 2009Co-Authors: Lise Lyngsnes Randeberg, Eivind L P Larsen, Lars O. SvaasandAbstract:Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin Bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400-1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify Bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectra from the images. The results show that hyperspectral images contain depth information, and that the approximate depth and extent of Bruises can be retrieved using a combination of statistical image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin.
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a novel approach to age determination of traumatic injuries by reflectance spectroscopy
Lasers in Surgery and Medicine, 2006Co-Authors: Lise Lyngsnes Randeberg, Olav A Haugen, Rune Haaverstad, Lars O. SvaasandAbstract:Background and Objectives Aging of injuries on a victim's body is an important aspect of forensic medicine. Currently, visual assessment and colorimetry based on empirical criteria are the most common techniques for this task, although the results are uncertain. A trauma causing localized vessel damage will rapidly result in a pool of blood in subcutaneous tissues. The color of the Bruise is, however, primarily due to hemoglobin transport into dermis and secondarily to its breakdown products. This transport is analyzed in terms of hemoglobin diffusion followed by clearance by macrophage activity, lymphatic flow, and conversion to breakdown products such as bilirubin. The color of a Bruise is caused by hemoglobin and hemoglobin breakdown products. The color will change with time, and such color changes can be recorded using reflectance spectroscopy. The aim of this study was to develop a mathematical model to describe blood diffusion within Bruised skin, and to use this method to retrieve the age of a Bruise from measured skin reflectance. Study Design/Materials and Methods An analytic model was established to describe the development and fading of Bruise color. The model, which is based on Darcy's law of convection flow and Fick's law of diffusion, describes the distribution of blood and hemoglobin breakdown products within a hematoma as a function of time after injury. The initial phase after injury is described by a convective extravascular blood flow in subcutaneous tissues, and further development of the Bruise is described by diffusion and breakdown of whole erythrocytes and hemoglobin in dermis. Experimental data were used to verify the model. Reflection spectra in the 400–850 nm wavelength range were collected from normal and Bruised skin using an integrating sphere setup. The subjects were adult patients admitted to the Department of cardiothoracic surgery, St. Olav's Hospital, Trondheim, Norway. The skin hematomas were caused by external trauma, cardiothoracic examinations, or surgery. Results Preliminary results show that measured and simulated skin reflectance agrees well. The model predicts the age of a hematoma with an accuracy of approximately 1 day. The accuracy of the method depends on precise information of skin thickness in the injured area. The quality of the estimates from the model will thus be enhanced if a reliable measure of skin thickness is collected concurrently with the reflection measurement. Conclusions The time development of a skin hematoma is described with good accuracy by the implemented model. The analytic method provides a theoretical basis for developing an apparatus to determine the age of injuries in forensic medicine. Lasers Surg. Med. 38:277–289, 2006. © 2006 Wiley-Liss, Inc.
Lise Lyngsnes Randeberg - One of the best experts on this subject based on the ideXlab platform.
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characterization of vascular structures and skin Bruises using hyperspectral imaging image analysis and diffusion theory
Journal of Biophotonics, 2009Co-Authors: Lise Lyngsnes Randeberg, Eivind L P Larsen, Lars O. SvaasandAbstract:Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin Bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400–1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify Bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectra from the images. The results show that hyperspectral images contain depth information, and that the approximate depth and extent of Bruises can be retrieved using a combination of statistical image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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characterization of vascular structures and skin Bruises using hyperspectral imaging image analysis and diffusion theory
Journal of Biophotonics, 2009Co-Authors: Lise Lyngsnes Randeberg, Eivind L P Larsen, Lars O. SvaasandAbstract:Hyperspectral imaging, image analysis and diffusion theory were used to visualize skin vasculature and to monitor the development of fresh skin Bruises. Bruises were inflicted in a porcine model, and the development of the hemorrhage was monitored using white light hyperspectral imaging (400-1000 nm). Hyperspectral images from human volunteers were also included in the study. Statistical image analysis was used to classify Bruised regions and to visualize the skin vasculature. Biopsies were collected from the animals to reveal the true depth of the bruising. A three-layer diffusion model and an analytic hemoglobin transport model were used to model the reflectance spectra from the images. The results show that hyperspectral images contain depth information, and that the approximate depth and extent of Bruises can be retrieved using a combination of statistical image analysis and diffusion theory. This technique also shows potential to visualize vascular structures in human skin.
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a novel approach to age determination of traumatic injuries by reflectance spectroscopy
Lasers in Surgery and Medicine, 2006Co-Authors: Lise Lyngsnes Randeberg, Olav A Haugen, Rune Haaverstad, Lars O. SvaasandAbstract:Background and Objectives Aging of injuries on a victim's body is an important aspect of forensic medicine. Currently, visual assessment and colorimetry based on empirical criteria are the most common techniques for this task, although the results are uncertain. A trauma causing localized vessel damage will rapidly result in a pool of blood in subcutaneous tissues. The color of the Bruise is, however, primarily due to hemoglobin transport into dermis and secondarily to its breakdown products. This transport is analyzed in terms of hemoglobin diffusion followed by clearance by macrophage activity, lymphatic flow, and conversion to breakdown products such as bilirubin. The color of a Bruise is caused by hemoglobin and hemoglobin breakdown products. The color will change with time, and such color changes can be recorded using reflectance spectroscopy. The aim of this study was to develop a mathematical model to describe blood diffusion within Bruised skin, and to use this method to retrieve the age of a Bruise from measured skin reflectance. Study Design/Materials and Methods An analytic model was established to describe the development and fading of Bruise color. The model, which is based on Darcy's law of convection flow and Fick's law of diffusion, describes the distribution of blood and hemoglobin breakdown products within a hematoma as a function of time after injury. The initial phase after injury is described by a convective extravascular blood flow in subcutaneous tissues, and further development of the Bruise is described by diffusion and breakdown of whole erythrocytes and hemoglobin in dermis. Experimental data were used to verify the model. Reflection spectra in the 400–850 nm wavelength range were collected from normal and Bruised skin using an integrating sphere setup. The subjects were adult patients admitted to the Department of cardiothoracic surgery, St. Olav's Hospital, Trondheim, Norway. The skin hematomas were caused by external trauma, cardiothoracic examinations, or surgery. Results Preliminary results show that measured and simulated skin reflectance agrees well. The model predicts the age of a hematoma with an accuracy of approximately 1 day. The accuracy of the method depends on precise information of skin thickness in the injured area. The quality of the estimates from the model will thus be enhanced if a reliable measure of skin thickness is collected concurrently with the reflection measurement. Conclusions The time development of a skin hematoma is described with good accuracy by the implemented model. The analytic method provides a theoretical basis for developing an apparatus to determine the age of injuries in forensic medicine. Lasers Surg. Med. 38:277–289, 2006. © 2006 Wiley-Liss, Inc.
Cathy S. Carlson - One of the best experts on this subject based on the ideXlab platform.
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Articular Cartilage Changes Seen With Magnetic Resonance Imaging-Detected Bone Bruises Associated With Acute Anterior Cruciate Ligament Rupture
The American journal of sports medicine, 1998Co-Authors: Darren L. Johnson, William P. Urban, David N.m. Caborn, William J. Vanarthos, Cathy S. CarlsonAbstract:Occult osteochondral lesions (bone Bruises) have been documented on magnetic resonance images in more than 80% of patients sustaining acute anterior cruciate ligament ruptures. Despite the high prevalence of these lesions, little is known about the histologic changes in the adjacent articular cartilage. Ten patients with acute anterior cruciate ligament ruptures who had a preoperatively documented (by magnetic resonance imaging) geographic bone Bruise at the sulcus terminalis on the lateral femoral condyle underwent a 3-mm diameter trephine biopsy of the articular cartilage and subchondral bone overlying the bone Bruise at the time of anterior cruciate ligament reconstruction. Biopsy samples of the articular cartilage and subchondral bone were stained with hematoxylin and eosin and toluidine blue. All patients had significant arthroscopic and histologic articular cartilage irregularity in the area overlying the bone Bruise. Arthroscopic findings of the articular cartilage included softening (dimpling), fissuring, or overt chondral fracture. Histologic examination revealed degeneration of the chondrocytes and loss of toluidine blue staining in the articular cartilage (loss of proteoglycan). There was necrosis of osteocytes in the subchondral bone, and empty lacuna were visible. This study defines the exact histologic changes of the articular cartilage overlying a geographic bone Bruise secondary to an acute anterior cruciate ligament tear. Our findings suggest that a geographic bone Bruise found on magnetic resonance imaging indicates substantial damage to normal articular cartilage homeostasis.
Louis E Defrate - One of the best experts on this subject based on the ideXlab platform.
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knee kinematics during noncontact anterior cruciate ligament injury as determined from bone Bruise location
American Journal of Sports Medicine, 2015Co-Authors: Sophia Y Kim, Charles E Spritzer, Gangadhar M Utturkar, Alison P Toth, William E Garrett, Louis E DefrateAbstract:Background:The motions causing noncontact anterior cruciate ligament (ACL) injury remain unclear. Tibiofemoral bone Bruises are believed to be the result of joint impact near the time of ACL rupture. The locations and frequencies of these bone Bruises have been reported, but there are limited data quantifying knee position and orientation near the time of injury based on these contusions.Hypothesis:Knee position and orientation near the time of noncontact ACL injury include extension and anterior tibial translation.Study Design:Descriptive laboratory study.Methods:Magnetic resonance images of 8 subjects with noncontact ACL injuries were acquired within 1 month of injury and were subsequently analyzed. All subjects exhibited Bruises on both the femur and tibia in both medial and lateral compartments. The outer margins of bone and the bone Bruise surfaces were outlined on each image to create a 3-dimensional model of each subject’s knee in its position during magnetic resonance imaging (MRI position). Numer...
Darren L. Johnson - One of the best experts on this subject based on the ideXlab platform.
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Articular Cartilage Changes Seen With Magnetic Resonance Imaging-Detected Bone Bruises Associated With Acute Anterior Cruciate Ligament Rupture
The American journal of sports medicine, 1998Co-Authors: Darren L. Johnson, William P. Urban, David N.m. Caborn, William J. Vanarthos, Cathy S. CarlsonAbstract:Occult osteochondral lesions (bone Bruises) have been documented on magnetic resonance images in more than 80% of patients sustaining acute anterior cruciate ligament ruptures. Despite the high prevalence of these lesions, little is known about the histologic changes in the adjacent articular cartilage. Ten patients with acute anterior cruciate ligament ruptures who had a preoperatively documented (by magnetic resonance imaging) geographic bone Bruise at the sulcus terminalis on the lateral femoral condyle underwent a 3-mm diameter trephine biopsy of the articular cartilage and subchondral bone overlying the bone Bruise at the time of anterior cruciate ligament reconstruction. Biopsy samples of the articular cartilage and subchondral bone were stained with hematoxylin and eosin and toluidine blue. All patients had significant arthroscopic and histologic articular cartilage irregularity in the area overlying the bone Bruise. Arthroscopic findings of the articular cartilage included softening (dimpling), fissuring, or overt chondral fracture. Histologic examination revealed degeneration of the chondrocytes and loss of toluidine blue staining in the articular cartilage (loss of proteoglycan). There was necrosis of osteocytes in the subchondral bone, and empty lacuna were visible. This study defines the exact histologic changes of the articular cartilage overlying a geographic bone Bruise secondary to an acute anterior cruciate ligament tear. Our findings suggest that a geographic bone Bruise found on magnetic resonance imaging indicates substantial damage to normal articular cartilage homeostasis.
