The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Svein Ødegaard - One of the best experts on this subject based on the ideXlab platform.
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Gastrointestinal Wall thickness measured with transabdominal ultrasonography and its relationship to demographic factors in healthy subjects.
Ultraschall in der Medizin (Stuttgart Germany : 1980), 2012Co-Authors: Kim Nylund, Svein Ødegaard, Trygve Hausken, Geir Egil Eide, Odd Helge GiljaAbstract:Purpose: To describe the Gastrointestinal (GI) Wall thickness and the thickness of individual Wall layers in healthy subjects using ultrasound and to determine whether demographic factors, the ultrasound transducer frequency, or a fasting state influences these measurements. Materials and Methods: After overnight fasting, the GI Wall thickness and Wall layers were measured in several regions with transabdominal, high-frequency ultrasound. 122 healthy subjects aged 23 – 79 were included. All measurements were performed with both 8 and 12-MHz transducers except for the rectum measurement (4 MHz). 23 patients were given a 300 Kcal test meal and re-examined after 30 minutes. Results: Wall thickness measurements of the GI tract with transabdominal ultrasonography are dependent on transducer frequency (p Conclusion: GI Wall thickness depends on weight and age. Provided adequate measurement, an abnormal GI Wall should be suspected if the thickness exceeds 2 mm except for in the gastric antrum, duodenum and rectum. Reference values for Wall thickness can be used regardless of fasting state or probe frequency except for in the gastric antrum.
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High-frequency ultrasonographic imaging of the Gastrointestinal Wall
Expert review of medical devices, 2012Co-Authors: Svein Ødegaard, L. B. Nesje, Ole Didrik Laerum, Michael B. KimmeyAbstract:The Gastrointestinal (GI) tract, with its layered structure, can be imaged by ultrasound using a transabdominal approach or intraluminal high-frequency probes. New ultrasound technology can be used to characterize tissue hardness, study motility in real-time, direct diagnostic and therapeutic intervention, evaluate GI Wall perfusion and tissue viability, and perform 3D imaging. Ultrasound is a safe imaging modality, and development of smaller devices has improved its application as a flexible clinical tool, which also can be used bedside. Recently, microbubbles have been injected into the blood stream loaded with contrast agents, or other diagnostic and therapeutic agents. Such bubbles can be destroyed by ultrasound waves, thus releasing their content at a given area of interest. In this article, we present a review of the GI Wall anatomy and discuss currently available ultrasound technology for diagnosis and treatment of GI Wall disorders.
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HOYFREKVENT ULTRASONOGRAFI AV GastrointestinalKANALENS VEGG
Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin ny raekke, 1996Co-Authors: Svein Ødegaard, A. H. S. Cheung, L. B. Nesje, Odd Helge Gilja, Trygve Hausken, Arnold Berstad, R. Eriksen, A. Skarstein, M. Wheeler, Michael B. KimmeyAbstract:If an ultrasound probe comes close to the area of interest, high ultrasound frequencies can be applied. Endoscopic ultrasonography is performed by means of echoendoscopes or miniature probes using ultrasound frequencies between 7 and 30 MHz. A high frequency ultrasound image of the normal Gastrointestinal Wall usually shows five layers corresponding closely to the histological layers of the Wall. Corrections have to be made, however, for interface echoes between layers with different acoustic impedances. We describe studies performed with the aim of correlating ultrasound images of the normal and diseased Gastrointestinal Wall with the histology. Ultrasound images of the normal Gastrointestinal Wall and pathological changes like ischemia, ulcers, tumours and inflammation are presented.
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The effects of applied pressure on the thickness, layers, and echogenicity of Gastrointestinal Wall ultrasound images
Gastrointestinal endoscopy, 1992Co-Authors: Svein Ødegaard, Michael B. Kimmey, Roy W. Martin, H.c. Yee, A. H. S. Cheung, Fred E. SilversteinAbstract:Endoscopic ultrasound imaging of the Gastrointestinal Wall can be performed through intraluminal fluid or by direct transducer contact with the Wall. We tested the hypothesis that the ultrasound appearance of the Gastrointestinal Wall is influenced by the amount of pressure applied when the transducer is in contact with the tissue. Fresh autopsy specimens from the porcine Gastrointestinal tract were examined in vitro using an 8.5-MHz linear array ultrasound system. As transducer pressure against the Wall was increased from 0 to 10KPa, changes were seen on the images in Wall thickness, tissue echogenicity, and the number of layers. The stomach and rectum were more resistant to compression than the esophagus, duodenum, and colon. Wall echogenicity increased with increasing degrees of applied pressure and some layers were obliterated by this pressure. The second ultrasound layer, or deep mucosa, appeared to be the most susceptible to compression. Endoscopic ultrasound imaging artifacts should be reduced by limiting the amount of pressure applied to the Wall with the transducer.
Michael B. Kimmey - One of the best experts on this subject based on the ideXlab platform.
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High-frequency ultrasonographic imaging of the Gastrointestinal Wall
Expert review of medical devices, 2012Co-Authors: Svein Ødegaard, L. B. Nesje, Ole Didrik Laerum, Michael B. KimmeyAbstract:The Gastrointestinal (GI) tract, with its layered structure, can be imaged by ultrasound using a transabdominal approach or intraluminal high-frequency probes. New ultrasound technology can be used to characterize tissue hardness, study motility in real-time, direct diagnostic and therapeutic intervention, evaluate GI Wall perfusion and tissue viability, and perform 3D imaging. Ultrasound is a safe imaging modality, and development of smaller devices has improved its application as a flexible clinical tool, which also can be used bedside. Recently, microbubbles have been injected into the blood stream loaded with contrast agents, or other diagnostic and therapeutic agents. Such bubbles can be destroyed by ultrasound waves, thus releasing their content at a given area of interest. In this article, we present a review of the GI Wall anatomy and discuss currently available ultrasound technology for diagnosis and treatment of GI Wall disorders.
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HOYFREKVENT ULTRASONOGRAFI AV GastrointestinalKANALENS VEGG
Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin ny raekke, 1996Co-Authors: Svein Ødegaard, A. H. S. Cheung, L. B. Nesje, Odd Helge Gilja, Trygve Hausken, Arnold Berstad, R. Eriksen, A. Skarstein, M. Wheeler, Michael B. KimmeyAbstract:If an ultrasound probe comes close to the area of interest, high ultrasound frequencies can be applied. Endoscopic ultrasonography is performed by means of echoendoscopes or miniature probes using ultrasound frequencies between 7 and 30 MHz. A high frequency ultrasound image of the normal Gastrointestinal Wall usually shows five layers corresponding closely to the histological layers of the Wall. Corrections have to be made, however, for interface echoes between layers with different acoustic impedances. We describe studies performed with the aim of correlating ultrasound images of the normal and diseased Gastrointestinal Wall with the histology. Ultrasound images of the normal Gastrointestinal Wall and pathological changes like ischemia, ulcers, tumours and inflammation are presented.
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The effects of applied pressure on the thickness, layers, and echogenicity of Gastrointestinal Wall ultrasound images
Gastrointestinal endoscopy, 1992Co-Authors: Svein Ødegaard, Michael B. Kimmey, Roy W. Martin, H.c. Yee, A. H. S. Cheung, Fred E. SilversteinAbstract:Endoscopic ultrasound imaging of the Gastrointestinal Wall can be performed through intraluminal fluid or by direct transducer contact with the Wall. We tested the hypothesis that the ultrasound appearance of the Gastrointestinal Wall is influenced by the amount of pressure applied when the transducer is in contact with the tissue. Fresh autopsy specimens from the porcine Gastrointestinal tract were examined in vitro using an 8.5-MHz linear array ultrasound system. As transducer pressure against the Wall was increased from 0 to 10KPa, changes were seen on the images in Wall thickness, tissue echogenicity, and the number of layers. The stomach and rectum were more resistant to compression than the esophagus, duodenum, and colon. Wall echogenicity increased with increasing degrees of applied pressure and some layers were obliterated by this pressure. The second ultrasound layer, or deep mucosa, appeared to be the most susceptible to compression. Endoscopic ultrasound imaging artifacts should be reduced by limiting the amount of pressure applied to the Wall with the transducer.
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Automatic layer detection in Gastrointestinal ultrasound images
Images of the Twenty-First Century. Proceedings of the Annual International Engineering in Medicine and Biology Society, 1Co-Authors: H.c. Yee, Michael B. Kimmey, Roy W. Martin, Fred E. SilversteinAbstract:An approach to the automatic boundary detection on Gastrointestinal-Wall ultrasound images (GWUI) is investigated. Boundaries are found by using the following major processing steps: asymmetrical two-dimensional median filtering; asymmetrical two-dimensional neighborhood averaging; global thresholding; binary image transformation; and local edge detection. Preliminary results from outlining layers within eight different GWUIs are presented. >
Lightdale C - One of the best experts on this subject based on the ideXlab platform.
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Endoscopic ultrasonography of the upper Gastrointestinal tract.
Radiologic clinics of North America, 1992Co-Authors: Lightdale CAbstract:Endoscopic ultrasonography combines the advantages of conventional endoscopy with the capabilities of ultrasonography. This permits the examiner to see through the Wall of the Gastrointestinal tract. The close proximity permits the use of relatively high frequencies, with the resulting increase in tissue contrast and resolution. There are limitations to its use, however, with the main one being a field of view limited to a 7-cm radius. Discussed in this article is its use for the Gastrointestinal Wall, the esophagus, the stomach, the duodenum, and the pancreas.
A. H. S. Cheung - One of the best experts on this subject based on the ideXlab platform.
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HOYFREKVENT ULTRASONOGRAFI AV GastrointestinalKANALENS VEGG
Tidsskrift for den Norske laegeforening : tidsskrift for praktisk medicin ny raekke, 1996Co-Authors: Svein Ødegaard, A. H. S. Cheung, L. B. Nesje, Odd Helge Gilja, Trygve Hausken, Arnold Berstad, R. Eriksen, A. Skarstein, M. Wheeler, Michael B. KimmeyAbstract:If an ultrasound probe comes close to the area of interest, high ultrasound frequencies can be applied. Endoscopic ultrasonography is performed by means of echoendoscopes or miniature probes using ultrasound frequencies between 7 and 30 MHz. A high frequency ultrasound image of the normal Gastrointestinal Wall usually shows five layers corresponding closely to the histological layers of the Wall. Corrections have to be made, however, for interface echoes between layers with different acoustic impedances. We describe studies performed with the aim of correlating ultrasound images of the normal and diseased Gastrointestinal Wall with the histology. Ultrasound images of the normal Gastrointestinal Wall and pathological changes like ischemia, ulcers, tumours and inflammation are presented.
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The effects of applied pressure on the thickness, layers, and echogenicity of Gastrointestinal Wall ultrasound images
Gastrointestinal endoscopy, 1992Co-Authors: Svein Ødegaard, Michael B. Kimmey, Roy W. Martin, H.c. Yee, A. H. S. Cheung, Fred E. SilversteinAbstract:Endoscopic ultrasound imaging of the Gastrointestinal Wall can be performed through intraluminal fluid or by direct transducer contact with the Wall. We tested the hypothesis that the ultrasound appearance of the Gastrointestinal Wall is influenced by the amount of pressure applied when the transducer is in contact with the tissue. Fresh autopsy specimens from the porcine Gastrointestinal tract were examined in vitro using an 8.5-MHz linear array ultrasound system. As transducer pressure against the Wall was increased from 0 to 10KPa, changes were seen on the images in Wall thickness, tissue echogenicity, and the number of layers. The stomach and rectum were more resistant to compression than the esophagus, duodenum, and colon. Wall echogenicity increased with increasing degrees of applied pressure and some layers were obliterated by this pressure. The second ultrasound layer, or deep mucosa, appeared to be the most susceptible to compression. Endoscopic ultrasound imaging artifacts should be reduced by limiting the amount of pressure applied to the Wall with the transducer.
Fred E. Silverstein - One of the best experts on this subject based on the ideXlab platform.
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The effects of applied pressure on the thickness, layers, and echogenicity of Gastrointestinal Wall ultrasound images
Gastrointestinal endoscopy, 1992Co-Authors: Svein Ødegaard, Michael B. Kimmey, Roy W. Martin, H.c. Yee, A. H. S. Cheung, Fred E. SilversteinAbstract:Endoscopic ultrasound imaging of the Gastrointestinal Wall can be performed through intraluminal fluid or by direct transducer contact with the Wall. We tested the hypothesis that the ultrasound appearance of the Gastrointestinal Wall is influenced by the amount of pressure applied when the transducer is in contact with the tissue. Fresh autopsy specimens from the porcine Gastrointestinal tract were examined in vitro using an 8.5-MHz linear array ultrasound system. As transducer pressure against the Wall was increased from 0 to 10KPa, changes were seen on the images in Wall thickness, tissue echogenicity, and the number of layers. The stomach and rectum were more resistant to compression than the esophagus, duodenum, and colon. Wall echogenicity increased with increasing degrees of applied pressure and some layers were obliterated by this pressure. The second ultrasound layer, or deep mucosa, appeared to be the most susceptible to compression. Endoscopic ultrasound imaging artifacts should be reduced by limiting the amount of pressure applied to the Wall with the transducer.
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Automatic layer detection in Gastrointestinal ultrasound images
Images of the Twenty-First Century. Proceedings of the Annual International Engineering in Medicine and Biology Society, 1Co-Authors: H.c. Yee, Michael B. Kimmey, Roy W. Martin, Fred E. SilversteinAbstract:An approach to the automatic boundary detection on Gastrointestinal-Wall ultrasound images (GWUI) is investigated. Boundaries are found by using the following major processing steps: asymmetrical two-dimensional median filtering; asymmetrical two-dimensional neighborhood averaging; global thresholding; binary image transformation; and local edge detection. Preliminary results from outlining layers within eight different GWUIs are presented. >
