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Radio-opaque Markers (radio-opaque + marker)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

A New Stent Design for the Treatment of True Bifurcation Lesions: H-Side Branch Stents

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2010
MYEONG-KI HONG M.D.
Background:There has been much debate for the adequate treatment strategies for true bifurcation lesions. The purpose of this study is to introduce and test a novel stent design for the treatment of true bifurcation lesions. Methods:This side branch stent is composed of three parts: proximal, connecting, and distal parts. The distal part for the side branch vessel has a slope-side stent margin for circumferential coverage of the ostium and one radio-opaque marker for targeting the carina. The proximal part with two radio-opaque markers operates for safe stent delivery and useful guidance for a more precise placement of the distal part on the side branch ostium. Results of the in vitro test in the acrylic resin-made bifurcation phantom model were evaluated with microcomputer tomography. Animal experiments with this new stent platform were also performed in five pigs. Results:In vitro test and microcomputer tomography showed complete coverage of the side branch ostium circumferentially with stent struts, and the absence of stent struts in the main vessel above the side branch ostium level. This side branch stents were successfully deployed in all 5 pigs. The results of animal experiments were also similar to those of in vitro tests. Conclusions:In vivo and vitro tests demonstrated the effective modality of this side branch stent for the treatment of true bifurcation lesions. (J Interven Cardiol 2010;23:54,59) [source]

An augmented reality system to guide radio-frequency tumour ablation

COMPUTER ANIMATION AND VIRTUAL WORLDS (PREV: JNL OF VISUALISATION & COMPUTER ANIMATION), Issue 1 2005
S. Nicolau
Abstract Radio-frequency ablation is a difficult operative task that requires a precise needle positioning in the centre of the pathology. This article presents an augmented reality system for hepatic therapy guidance that superimposes in real-time 3D reconstructions (from CT acquisition) and a virtual model of the needle on external views of a patient. The superimposition of reconstructed models is performed with a 3D/2D registration based on radio-opaque markers stuck on to the patient's skin. The characteristics of the problem (accuracy, robustness and time processing) led us to develop automatic procedures to extract and match the markers and to track the needle in real time. Experimental studies confirmed that our algorithms are robust and reliable. Preliminary experiments conducted on a human abdomen phantom showed that our system is highly accurate (needle positioning error within 3,mm) and enables the surgeon to reach a target in less than 1 minute on average. Our next step will be to perform an in vivo evaluation. Copyright © 2005 John Wiley & Sons, Ltd. [source]

A New Stent Design for the Treatment of True Bifurcation Lesions: H-Side Branch Stents

Actions of prolonged ghrelin infusion on gastrointestinal transit and glucose homeostasis in humans

NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2010
Y. Falkén
Abstract Background, Ghrelin is produced by enteroendocrine cells in the gastric mucosa and stimulates gastric emptying in healthy volunteers and patients with gastroparesis in short-term studies. The aim of this study was to evaluate effects of intravenous ghrelin on gastrointestinal motility and glucose homeostasis during a 6-h infusion in humans. Methods, Ghrelin (15 pmol kg,1 min,1) or saline was infused intravenously for 360 min after intake of radio-opaque markers, acetaminophen, and lactulose after a standardized breakfast in 12 male volunteers. Gastric emptying, orocecal transit, colonic transit, postprandial plasma concentrations of glucose, insulin, glucagon-like peptide-1 (GLP-1), and peptide YY were assessed. In vitro studies of gastrointestinal muscle contractility were performed. Key Results, The gastric emptying rate was faster for ghrelin compared to saline (P = 0.002) with a shorter half-emptying time (50.3 ± 3.9 vs 59.9 ± 4.4 min, P = 0.004). There was no effect of ghrelin on orocecal or colonic transit. Postprandial elevations of plasma glucose, insulin, and GLP-1 occurred 15 min earlier and were higher with ghrelin. The insulinogenic index did not change during ghrelin infusion. Basal in vitro contractility was unaffected by ghrelin. Conclusions & Inferences, The effect of a 6-h ghrelin infusion on gastrointestinal motility is limited to the stomach without affecting orocecal or colonic transit. Plasma glucose, insulin, and GLP-1 are elevated postprandially, probably as a result of the hastened gastric emptying. Changes in glucose homeostasis as a consequence of stimulated gastric emptying and hormone release, need to be taken into account in the use of pharmacological stimulants for the treatment of motility disorders. [source]

Sacral nerve stimulation for faecal incontinence alters colorectal transport,,

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 6 2008
H. B. Michelsen
Background: Sacral nerve stimulation reduces the frequency of defaecation in patients with faecal incontinence. The aim of this study was to examine the mechanism behind the reduced number of bowel movements in incontinent patients treated with sacral nerve stimulation. Methods: The study included 20 patients with faecal incontinence and a positive percutaneous nerve evaluation test: 19 women and one man, with a median age of 63 (range 28,78) years. Colorectal scintigraphy was performed to assess colorectal emptying at defaecation before and after implantation. Segmental colorectal transit times were determined using radio-opaque markers. Results: The median frequency of defaecation per 3 weeks decreased from 56 (range 19,136) to 26 (range 12,78) (P < 0·002). At defaecation, antegrade transport from the ascending colon decreased from a median score of 8 (range 0,23) to 0 (range 0,11) per cent (P = 0·001), while retrograde transport from the descending colon increased from a median score of 0 (range 0,14) to 2 (range 0,30) per cent (P = 0·039). The median defaecation score was unchanged. There was a non-significant increase in median total gastrointestinal transit time from 2·5 (range 0·9,6·2) to 3·3 (range 0·8,6·2) days (P = 0·079). Conclusion: Sacral nerve stimulation reduces antegrade transport from the ascending colon and increases retrograde transport from the descending colon at defaecation. This may prolong colonic transit time and increase the storage capacity of the colon. Copyright © 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source]