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Quantitative and Qualitative Assessment of the Myocardium at Risk

Ubachs, Joey LU (2011) In Lund University, Faculty of Medicine Doctoral Dissertation Series 2011:71.
Abstract (Swedish)
Popular Abstract in Swedish

Under de senaste 10 åren har antalet människor i Sverige som dör av akut hjärtinfarkt minskat stadigt. Den äldre befolkningen är dock växande och med ökande antal människor med fetma och typ II-diabetes, står vi inför en stor utmaning i framtiden vad gäller hantering av patienter med akut hjärtinfarkt. För att möta denna utmaning är det viktigt att öka vår förmåga att behandla akut hjärtinfarkt. Korrekt behandling har dock alltid förlitat sig på korrekt diagnos. Ökad noggrannhet och precision av diagnostisk prestanda är därför viktigt, inte bara för den enskilda patienten men också för samhället, eftersom en liten behandlingsvinst kan ge stora besparingar på grund av det stora antalet patienter.... (More)
Popular Abstract in Swedish

Under de senaste 10 åren har antalet människor i Sverige som dör av akut hjärtinfarkt minskat stadigt. Den äldre befolkningen är dock växande och med ökande antal människor med fetma och typ II-diabetes, står vi inför en stor utmaning i framtiden vad gäller hantering av patienter med akut hjärtinfarkt. För att möta denna utmaning är det viktigt att öka vår förmåga att behandla akut hjärtinfarkt. Korrekt behandling har dock alltid förlitat sig på korrekt diagnos. Ökad noggrannhet och precision av diagnostisk prestanda är därför viktigt, inte bara för den enskilda patienten men också för samhället, eftersom en liten behandlingsvinst kan ge stora besparingar på grund av det stora antalet patienter. Identifiering och kvantifiering av det ischemiska område, även kallat för riskarea, i den akuta fasen av ischemi har varit svårt på patienter med konventionella metoder, t.ex. scintigrafi eller elektrokardiogram. Om man vill undersöka nya behandlingsstrategier, med syfte att reducera infarktstorlek, behövs tillförlitliga mått på både infarktstorlek och riskarea för att kunna bedöma hur mycket som räddas med hjälp av olika behandlingsstrategier. Denna avhandlingen har i stor grad ökat kunskapen kring möjligheten att kunna bestämma riskarea med hjälp av magnetresonancetomografi (MR).

Delarbete I visade för första gången i människa att riskarea med T2-viktad MR, vilket visar ödem i hjärtmuskeln, korrelerade med scintigrafi (referensmetod för bestämning av riskarea). Studien visade även att T2-viktad MR kan användas för bestämning av riskarea upp till en vecka efter reperfusionsbehandling. Vid jämförelse med infarkstorlek sågs att stora delar av riskarean hade räddats genom reperfusionbehandling.

I delarbete II undersöktes sambandet mellan riskarea mätt med T2-viktad MR och den endokardiella utbredningen av infarktstorlek mätt med kontrastförstärkt MR. Studien visade en signifikant skillnad mellan dessa två metoder för att bestämma riskarea. Studien visade att den endokardiella utbredningen av infarkt kan inte användas för att bestämma riskarea hos patienter med tidig reperfusionsbehandling med liten eller ingen infarkt som följd.

I delarbete III studerades hur riskarea vid reperfunderad förstagångsinfarkt mätt med T2-viktad MR förhåller sig till riskarea mätt med funktionsbilder tidigt efter kontrastinjektion (EGE). Studien visade ett starkt samband mellan de två olika metoderna för att bedöma riskarea. Slutsatsen från denna studie är att både T2-viktad MR och EGE kan användas för att bedöma riskarea och räddad hjärtmuskel.

Delarbete IV visade att T2-viktad MR i en ex vivo modell i gris kan användas för att bedöma riskarea. Dessutom studerades om T2-viktad MR kan användas för att bedöma riskarea efter injektion av MR-kontrastmedel innehållande gadolinium. Resultaten visade att riskarea på T2-viktade bilder, med och utan kontrast, korrelerade starkt med scintigrafi. (Less)
Abstract
One of the major determinants of the final infarct size during an acute coronary occlusion is the size of the myocardium subjected to ischemia. Identification and quantification of this so-called myocardium at risk in the acute phase of ischemia has been difficult in patients with conventional methods, such as myocardial perfusion single-photon emission computed tomography (SPECT) or electrocardiography. However, to assess cardioprotective strategies aimed at reducing infarct size, an accurate measure of both myocardium at risk and infarct size is needed. Both measurements are necessary in order to assess the amount of myocardium that has been salvaged by the provided treatment. Cardiac magnetic resonance imaging (CMR) has the opportunity... (More)
One of the major determinants of the final infarct size during an acute coronary occlusion is the size of the myocardium subjected to ischemia. Identification and quantification of this so-called myocardium at risk in the acute phase of ischemia has been difficult in patients with conventional methods, such as myocardial perfusion single-photon emission computed tomography (SPECT) or electrocardiography. However, to assess cardioprotective strategies aimed at reducing infarct size, an accurate measure of both myocardium at risk and infarct size is needed. Both measurements are necessary in order to assess the amount of myocardium that has been salvaged by the provided treatment. Cardiac magnetic resonance imaging (CMR) has the opportunity to accurately assess both the myocardium at risk as well as the infarct size. This thesis has contributed to the knowledge on quantification of the myocardium at risk and subsequently myocardial salvage with the use of CMR imaging.

Study I demonstrated, for the first time in humans, that there was a good correlation between the myocardium at risk assessed by T2-weighted CMR, which shows myocardial edema, and the myocardium at risk assessed by myocardial perfusion SPECT. Furthermore, the study also showed that T2-weighted CMR can be used up to 1 week after reperfusion therapy, allowing assessment of both myocardium at risk and infarct size to determine myocardial salvage in a single imaging session, without interfering with patient care.

Study II showed a significant difference between the myocardium at risk assessed by T2-weighted CMR and the endocardial extent of infarction measured by late gadolinium enhancement. Thus, endocardial extent of infarction can not be used to determine myocardium at risk, especially in patients with early reperfusion therapy with little or no infarction.

Study III demonstrated a good correlation between the myocardium at risk assessed by T2-weighted CMR and the myocardium at risk assessed by cine imaging early after injection of a gadolinium-based contrast agent, in patients 1 week after acute coronary occlusion. Thus, both methods can be used simultaneously or separately to determine MaR and subsequently myocardial salvage in a single imaging session.

Finally, Study IV showed that T2-weighted CMR can be used to determine the myocardium at risk in an ex vivo experimental model, both with and without the presence of gadolinium. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Friedrich, Matthias, University of Calgary/ University of Montreal
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Acute myocardial infarction, Myocardium at Risk, magnetic resonance imaging, T2-weighted imaging, Myocardial perfusion SPECT
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
volume
2011:71
pages
87 pages
publisher
Department of Clinical Physiology, Lund University
defense location
Förekäsningssal 3, Skåne University Hospital, Lund
defense date
2011-09-02 09:00
ISSN
1652-8220
ISBN
978-91-86871-21-5
language
English
LU publication?
yes
id
59751aa3-acc9-4cbc-9de1-3769d221fa77 (old id 2062011)
date added to LUP
2011-08-09 11:43:48
date last changed
2016-09-19 08:44:50
@phdthesis{59751aa3-acc9-4cbc-9de1-3769d221fa77,
  abstract     = {One of the major determinants of the final infarct size during an acute coronary occlusion is the size of the myocardium subjected to ischemia. Identification and quantification of this so-called myocardium at risk in the acute phase of ischemia has been difficult in patients with conventional methods, such as myocardial perfusion single-photon emission computed tomography (SPECT) or electrocardiography. However, to assess cardioprotective strategies aimed at reducing infarct size, an accurate measure of both myocardium at risk and infarct size is needed. Both measurements are necessary in order to assess the amount of myocardium that has been salvaged by the provided treatment. Cardiac magnetic resonance imaging (CMR) has the opportunity to accurately assess both the myocardium at risk as well as the infarct size. This thesis has contributed to the knowledge on quantification of the myocardium at risk and subsequently myocardial salvage with the use of CMR imaging.<br/><br>
Study I demonstrated, for the first time in humans, that there was a good correlation between the myocardium at risk assessed by T2-weighted CMR, which shows myocardial edema, and the myocardium at risk assessed by myocardial perfusion SPECT. Furthermore, the study also showed that T2-weighted CMR can be used up to 1 week after reperfusion therapy, allowing assessment of both myocardium at risk and infarct size to determine myocardial salvage in a single imaging session, without interfering with patient care.<br/><br>
Study II showed a significant difference between the myocardium at risk assessed by T2-weighted CMR and the endocardial extent of infarction measured by late gadolinium enhancement. Thus, endocardial extent of infarction can not be used to determine myocardium at risk, especially in patients with early reperfusion therapy with little or no infarction. <br/><br>
Study III demonstrated a good correlation between the myocardium at risk assessed by T2-weighted CMR and the myocardium at risk assessed by cine imaging early after injection of a gadolinium-based contrast agent, in patients 1 week after acute coronary occlusion. Thus, both methods can be used simultaneously or separately to determine MaR and subsequently myocardial salvage in a single imaging session. <br/><br>
Finally, Study IV showed that T2-weighted CMR can be used to determine the myocardium at risk in an ex vivo experimental model, both with and without the presence of gadolinium.},
  author       = {Ubachs, Joey},
  isbn         = {978-91-86871-21-5},
  issn         = {1652-8220},
  keyword      = {Acute myocardial infarction,Myocardium at Risk,magnetic resonance imaging,T2-weighted imaging,Myocardial perfusion SPECT},
  language     = {eng},
  pages        = {87},
  publisher    = {Department of Clinical Physiology, Lund University},
  school       = {Lund University},
  series       = {Lund University, Faculty of Medicine Doctoral Dissertation Series},
  title        = {Quantitative and Qualitative Assessment of the Myocardium at Risk},
  volume       = {2011:71},
  year         = {2011},
}