The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Xavier Golay - One of the best experts on this subject based on the ideXlab platform.
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MR Regional Perfusion imaging: visualizing functional collateral circulation.
AJNR. American journal of neuroradiology, 2007Co-Authors: C.c.t. Lim, Esben Thade Petersen, P.y.k. Hwang, Francis Hui, Xavier GolayAbstract:We applied Regional Perfusion imaging (RPI), a new arterial spin-labeling MR imaging method that selectively studies regions of the brain perfused by individual carotid and basilar arteries. In a patient with cerebrovascular disease, RPI showed cerebral tissue perfused by pial collateral vessels, thereby demonstrating the relationship between anatomic and functional information, which was lacking in conventional x-ray angiography. RPI may be useful to study functional collateral circulation and hence guide therapy in ischemic disease.
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Dual vessel arterial spin labeling scheme for Regional Perfusion imaging.
Magnetic resonance in medicine, 2006Co-Authors: Ivan Zimine, Esben Thade Petersen, Xavier GolayAbstract:Regional Perfusion imaging (RPI) based on pulsed arterial spin labeling and angulated inversion slabs has been recently proposed. The technique allows mapping of individual brain Perfusion territories of the major feeding arteries and could become a valuable clinical tool for evaluation of patients with cerebrovascular diseases. Here we propose a new labeling scheme for RPI where lateral and posterior circulations are labeled simultaneously. Two scans instead of three are sufficient to obtain the same Perfusion territories as in the original approach, allowing for a 33% reduction in the total RPI protocol time. Moreover, the position of the inversion slabs with respect to vascular anatomy facilitates the planning and allows potentially better labeling efficiency. The new approach was tested on seven healthy volunteers and compared to the original labeling scheme. The results showed that the same Perfusion territories and Regional CBF values can be obtained.
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pulsed star labeling of arterial regions pulsar a robust Regional Perfusion technique for high field imaging
Magnetic Resonance in Medicine, 2005Co-Authors: Xavier Golay, Esben Thade Petersen, Francis HuiAbstract:Regional Perfusion imaging (RPI) has recently been introduced as a potentially powerful technique to map the Perfusion territories of patients with vascular diseases in a fully noninvasive manner. However, this technique suffers from the problems of the transfer insensitive labeling technique upon which it is based. In particular, RPI is very sensitive to magnetic field inhomogeneities, and therefore the definition of the labeled bolus can deteriorate at field strength higher than 1.5 T. Furthermore, the slab-selective triple-pulse postsaturation sequence used originally will also be impaired due to the same problem, rendering RPI unusable at higher field. In this work, an adiabaticbased signal targeting with alternating radiofrequency pulses sequence is proposed as a labeling scheme to solve the problems related to variations in local magnetic field, together with an improved four-pulse water suppression enhanced through T1 effects technique as a presaturation scheme. Magn Reson Med 53: 15–21, 2005. © 2004 Wiley-Liss, Inc.
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flow territory mapping of the cerebral arteries with Regional Perfusion mri
Stroke, 2004Co-Authors: Jeroen Hendrikse, Jeroen Van Der Grond, Peter C M Van Zijl, Xavier GolayAbstract:Background and Purpose— Conventional contrast-enhanced angiography is the gold standard for visualization of the vascular tree supplied by the major cerebral arteries and assessment of collateral flow. Thus far, however, no methods are available to assess the actual flow territories of the individual cerebral arteries. In the present study, we evaluate a noninvasive arterial spin labeling MRI method for selective mapping of the flow territories of the left and right internal carotid arteries and posterior circulation (basilar artery and vertebral arteries). Methods— A spatially selective labeling approach, Regional Perfusion imaging, was developed on the basis of selective slab inversion of the arterial water with a pulsed arterial spin labeling sequence. The selectivity of this method was demonstrated. Results— Regional Perfusion imaging enables assessment of the Perfusion territories of the major cerebral arteries. With selective labeling of an internal carotid artery, signal is present in both the ipsi...
V Mitrovic - One of the best experts on this subject based on the ideXlab platform.
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Effects of nicorandil on Regional Perfusion and left ventricular function
Cardiovascular Drugs and Therapy, 1995Co-Authors: M Schlepper, J Thormann, K Berwing, R Strasser, V MitrovicAbstract:Left ventricular function and Regional Perfusion were evaluated by two study designs in patient groups with stable ischemic coronary artery disease (CAD): (1) using conventional left ventricular angiographies and (2) applying myocardial contrast echocardiography. The aim of the studies was to establish the effects of sublingually or orally applied nicorandil (N) on pacing-induced myocardial ischemia (MIS). In the first angiographic study, in nine patients with ischemic CAD and with pacing-inducible MIS, the effect of N, 20 mg sublingually, on hemodynamics and Regional wall motion (RWM) were studied. There were no parameter changes without MIS being induced when comparing measurements at the 7th and 14th minute after N application to control values (p>0.05). In the 15th and 16th minutes after N, pacing-induced MIS could no longer be elicited but left ventricular pump function improved; comparing MIS with N versus MIS without N: ejection fraction improved by 21%, cardiac index by 37%, and RWM by 21%, while filling pressure fell by 41% and systemic vascular resistance fell by 29%. Thus, N-mediated “protection from ischemia” with rather improved hemodynamics and RWM corresponds with alterations that theoretically could have been expected after nitroglycerin given under the above conditions. In the second echocardiographic study, Regional Perfusion was assessed in 10 patients by intracoronary injection of a newly developed echo contrast medium (ECM) and measurement of ECM washout halftime (t_1/2) over opacified myocardial regions of interest, which displayed wall motion abnormalities already at rest. Echocardiographic evaluations were performed at rest and during MIS with and without the effects of 20 mg of oral N. The t_1/2 shortened significantly by 60% and was accompanied by a decrease in filling pressure from 18±9 to 7±3 mmHg. The perfused myocardial area increased by 75%, displaying a partially regained wall motion in previously hypokinetic areas, which resulted in an augmentation of Regional ejection fraction. Concomitantly, the degree of coronary stenoses was reduced by 21% (p
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Effects of nicorandil on Regional Perfusion and left ventricular function.
Cardiovascular drugs and therapy, 1995Co-Authors: M Schlepper, J Thormann, K Berwing, R Strasser, V MitrovicAbstract:Left ventricular function and Regional Perfusion were evaluated by two study designs in patient groups with stable ischemic coronary artery disease (CAD): (1) using conventional left ventricular angiographies and (2) applying myocardial contrast echocardiography. The aim of the studies was to establish the effects of sublingually or orally applied nicorandil (N) on pacing-induced myocardial ischemia (MIS). In the first angiographic study, in nine patients with ischemic CAD and with pacing-inducible MIS, the effect of N, 20 mg sublingually, on hemodynamics and Regional wall motion (RWM) were studied. There were no parameter changes without MIS being induced when comparing measurements at the 7th and 14th minute after N application to control values (p > 0.05). In the 15th and 16th minutes after N, pacing-induced MIS could no longer be elicited but left ventricular pump function improved; comparing MIS with N versus MIS without N: ejection fraction improved by 21%, cardiac index by 37%, and RWM by 21%, while filling pressure fell by 41% and systemic vascular resistance fell by 29%. Thus, N-mediated "protection from ischemia" with rather improved hemodynamics and RWM corresponds with alterations that theoretically could have been expected after nitroglycerin given under the above conditions. In the second echocardiographic study, Regional Perfusion was assessed in 10 patients by intracoronary injection of a newly developed echo contrast medium (ECM) and measurement of ECM washout halftime (t1/2) over opacified myocardial regions of interest, which displayed wall motion abnormalities already at rest.(ABSTRACT TRUNCATED AT 250 WORDS)
Jean Paul Lavigne - One of the best experts on this subject based on the ideXlab platform.
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successful clinical transplantation of hearts donated after circulatory death using normothermic Regional Perfusion
Journal of Heart and Lung Transplantation, 2019Co-Authors: Vincent Tchanasato, Didier Ledoux, Grégory Hans, Arnaud Ancion, Philippe Amabili, Olivier Detry, Paul Massion, Virginie Dorio, Samuel Bruls, Jean Paul LavigneAbstract:BACKGROUND Heart transplantation (HT) from donation after circulatory death (DCD) has yet to achieve wide clinical application despite the encouraging resultsreported recently. In this study we describe 2 cases of successful adult DCD HT performed at our institution using an original protocol. METHODS Our local abdominal DCD protocol was updated to allow DCD heart procurement, and was accepted by the institutional ethics committee. The main features of the protocol include: pre-mortem insertion of peripheral venoarterial extracorporeal membrane oxygenation cannulas; thoracoabdominal normothermic Regional Perfusion (NRP) by clamping the 3 aortic arch vessels to exclude cerebral circulation; and in-situ heart resuscitation. The retrieved hearts were directly transplanted into recipients located in an adjoining operating room. RESULTS The procurement warm ischemic time was 25 minutes for the first donor, and 26 minutes for the second donor. The cold ischemic time was 16 minutes for the first recipient and 17 minutes for the second recipient. The suture time was 30 minutes for the first recipient, and 53 minutes for the second recipient. Both recipients were easily weaned off cardiopulmonary bypass in sinus rhythm and inotropic support. Post-operative evaluation of cardiac function was excellent and the patients were subsequently discharged home. CONCLUSIONS Transplantation of hearts from DCD donors is now a clinical reality.NRP is a useful tool for resuscitation, rePerfusion, and preservation of transplanted hearts. It also offers the opportunity to assess the function and viability of organs before transplantation. However,due to ethical issues, some may object to ante-mortem intervention.
Gabriel C Oniscu - One of the best experts on this subject based on the ideXlab platform.
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Better Graft Survival with no Ischemic Cholangiopathy in DCD Liver Transplantation in the UK using Normothermic Regional Perfusion (NRP)
Transplantation, 2018Co-Authors: Gabriel C Oniscu, S. Messer, Stephen R. Large, Andrew J Butler, Fiona Hunt, Andrew P. R. Sutherland, Ian Currie, Sarah Upon, John D. Terrace, Chris J. WatsonAbstract:BackgroundNormothermic Regional Perfusion, whereby the donor is placed on an extracorporeal circuit to circulate oxygenated blood to the abdominal viscera after death, is increasingly being used in controlled donation after circulatory death (DCD) donation. We evaluated the joint experience of the t
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extending normothermic Regional Perfusion to the thorax in donors after circulatory death
Current Opinion in Organ Transplantation, 2017Co-Authors: Steve S L Tsui, Gabriel C OniscuAbstract:PURPOSE OF REVIEW: Despite a significant increase in the utilization of donors after circulatory death (DCD), the number of organs recovered and their function are largely inferior to those from donors after brain death. This review summarizes recent advances in in-situ normothermic Regional Perfusion of DCD organs prior to procurement. RECENT FINDINGS: The combination of warm and cold ischemia in DCD donation are detrimental to organ function. As a consequence, the acceptance criteria are far more restrictive and many organs are discarded.The application of extracorporeal circulation technology to DCD organ retrieval in the form of abdominal normothermic Regional Perfusion (NRP) made a significant impact on organ procurement. DCD heart transplantation has been made possible by technological developments of ex-situ preservation. Extending NRP to include cardio-thoracic organs is a recent development enabling conversion from a DCD to a donor after brain death-type procurement.NRP offers the opportunity for a dynamic assessment of function and may lead to expansion of acceptance criteria as well as allowing for early interventions to modulate organ function. SUMMARY: Thoraco-abdominal NRP may become the new gold standard for DCD organ retrieval. Further research and education are required to streamline logistics, define organ function markers and increase acceptance and utilization.
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in situ normothermic Regional Perfusion for controlled donation after circulatory death the united kingdom experience
American Journal of Transplantation, 2014Co-Authors: Gabriel C Oniscu, Andrew J Butler, Lucy V. Randle, Ian Currie, Paolo Muiesan, M T P R Perera, John Forsythe, Christopher J E WatsonAbstract:Organs recovered from donors after circulatory death (DCD) suffer warm ischemia before cold storage which may prejudice graft survival and result in a greater risk of complications after transplant. A period of normothermic Regional Perfusion (NRP) in the donor may reverse these effects and improve organ function. Twenty-one NRP retrievals from Maastricht category III DCD donors were performed at three UK centers. NRP was established postasystole via aortic and caval cannulation and maintained for 2 h. Blood gases and biochemistry were monitored to assess organ function. Sixty-three organs were recovered. Forty-nine patients were transplanted. The median time from asystole to NRP was 16 min (range 10-23 min). Thirty-two patients received a kidney transplant. The median cold ischemia time was 12 h 30 min (range 5 h 25 min-18 h 22 min). The median creatinine at 3 and 12 months was 107 µmol/L (range 72-222) and 121 µmol/L (range 63-157), respectively. Thirteen (40%) recipients had delayed graft function and four lost the grafts. Eleven patients received a liver transplant. The first week median peak ALT was 389 IU/L (range 58-3043). One patient had primary nonfunction. Two combined pancreas-kidney transplants, one islet transplant and three double lung transplants were performed with primary function. NRP in DCD donation facilitates organ recovery and may improve short-term outcomes.
Christopher J E Watson - One of the best experts on this subject based on the ideXlab platform.
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direct procurement of donor heart with normothermic Regional Perfusion of abdominal organs
The Annals of Thoracic Surgery, 2019Co-Authors: Prashant N Mohite, Diana Garcia Saez, Andrew J Butler, Christopher J E Watson, A R SimonAbstract:Purpose We wanted to evaluate if direct procurement of the heart is possible in combination with normothermic Regional Perfusion of abdominal organs in donors after circulatory death. Description A donation after circulatory death pathway was used for a 41-year-old woman after an irreversible brain injury. After meeting criteria for the organ donation, the heart was retrieved and re-animated on ex situ Perfusion system, and abdominal organs were perfused with normothermic Regional Perfusion. Evaluation All the donated organs and their recipients had excellent short-term outcome. Conclusions We demonstrated a successful combination of direct procurement of the heart and normothermic Regional Perfusion of the abdominal organs.
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in situ normothermic Regional Perfusion for controlled donation after circulatory death the united kingdom experience
American Journal of Transplantation, 2014Co-Authors: Gabriel C Oniscu, Andrew J Butler, Lucy V. Randle, Ian Currie, Paolo Muiesan, M T P R Perera, John Forsythe, Christopher J E WatsonAbstract:Organs recovered from donors after circulatory death (DCD) suffer warm ischemia before cold storage which may prejudice graft survival and result in a greater risk of complications after transplant. A period of normothermic Regional Perfusion (NRP) in the donor may reverse these effects and improve organ function. Twenty-one NRP retrievals from Maastricht category III DCD donors were performed at three UK centers. NRP was established postasystole via aortic and caval cannulation and maintained for 2 h. Blood gases and biochemistry were monitored to assess organ function. Sixty-three organs were recovered. Forty-nine patients were transplanted. The median time from asystole to NRP was 16 min (range 10-23 min). Thirty-two patients received a kidney transplant. The median cold ischemia time was 12 h 30 min (range 5 h 25 min-18 h 22 min). The median creatinine at 3 and 12 months was 107 µmol/L (range 72-222) and 121 µmol/L (range 63-157), respectively. Thirteen (40%) recipients had delayed graft function and four lost the grafts. Eleven patients received a liver transplant. The first week median peak ALT was 389 IU/L (range 58-3043). One patient had primary nonfunction. Two combined pancreas-kidney transplants, one islet transplant and three double lung transplants were performed with primary function. NRP in DCD donation facilitates organ recovery and may improve short-term outcomes.
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Normothermic Regional Perfusion for donation after circulatory death without prior heparinization.
Transplantation, 2014Co-Authors: Andrew J Butler, Lucy V. Randle, Christopher J E WatsonAbstract:Background Over 40% of deceased donors in the UK donate after circulatory death (DCD). Normothermic Regional Perfusion has been reported to improve outcomes in such donors in Europe and the United States. Unlike the United States, legal and professional requirements in the UK prevent cannulation and heparinization before verification of death, which must be a minimum of 5 min after circulatory arrest. We developed a novel protocol for in situ normothermic Regional Perfusion (NRP) which complied with these requirements. Methods NRP was achieved by cannulating the aorta and vena cava after death. Donor blood was then warmed and oxygenated using a bespoke extracorporeal membrane oxygenator circuit before return to the donor. A shunt was incorporated into the extracorporeal circuit to permit heparin mixing before oxygenation and warming was commenced to prevent thrombosis of the oxygenator. Normothermic Perfusion was continued for 2 hr before in situ cold Perfusion with preservation fluid. All organs were subject to static cold storage after recovery. Results Eight controlled DCD donors underwent NRP from which 3 livers, 2 pancreases, and 14 kidneys were transplanted. Four livers were not used because of biochemical evidence of hepatocellular damage and one because of cirrhosis. Two kidneys were lost from venous thrombosis before function returned and two developed delayed graft function; all transplanted livers and pancreases had primary function. Conclusions Cannulation and heparinization after circulatory arrest does not prevent successful normothermic Regional Perfusion. The technique permits evaluation of donor organs before implantation and may improve short-term outcomes.
