uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Myocardial Scars on MRI: Their Prevalence and Possible Impact
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology.
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Myocardial infarction (MI) causes high morbidity and mortality worldwide and for effective prevention and treatment MIs have to be adequately detected.

The existence of clinically unrecognized MIs (UMIs) has been known for the past hundred years, but an ultimate tool for their detection has not yet been found. Using persistent Q waves on electrocardiography as a sign of MI, it has been estimated that UMIs constitute at least ¼ of all MIs and have mortality rates similar to those of recognized MIs (RMIs). These estimates are misleading, however, since persistent Q waves do not necessarily represent MIs.

The late enhancement technique in magnetic resonance imaging (LE MRI) has been developed over the past decade and accurately determines myocardial viability. The aim of this research was to investigate the prevalence and impact of UMI and RMI in a population-based sample of 70-year-olds, assessed with MRI.

Cardiac function and viability were examined with MRI in 259 randomly selected 70-year-old subjects (127 women, 132 men) participating in a larger population-based study (PIVUS). Information on other parameters of cardiovascular disease was obtained and related to the findings.

Three methods for segmentation of the left ventricular mass were used in the first 100 subjects; these differed in accuracy and led to differences in systolic function values. In the subsequent 159 examinations one of the segmentation methods was used.

The viability images were assessable in 248 subjects (123 women, 125 men). Among these, the prevalence of UMI, 19.8%, definitely exceeded the expectations and UMIs constituted 4/5 of all MIs. The prevalence of RMI was 4.4%. MRI-detected UMIs differed from RMIs in several respects; they were smaller, frequently located inferolaterally, did not appear to be associated with atherosclerosis, and displayed increased collagen turnover. The pathogenesis of these UMIs remains to be investigated, but our observations suggest that they are caused by ischemia. Subjects with UMI showed increased cardiac morbidity, a decreased ejection fraction and an increased left ventricular mass, indicating an increased cardiovascular risk.

It is thus important to detect these UMIs, and this is adequately achieved by LE MRI. However, to decide upon prevention and treatment of these UMIs we need to know more about their pathogenesis and prognosis.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 2007. , p. 89
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 227
Keywords [en]
Radiology, magnetic resonance imaging, myocardial infarction, epidemiology, myocardial infarction, epidemiology
Keywords [sv]
Radiologisk forskning
Identifiers
URN: urn:nbn:se:uu:diva-7548ISBN: 978-91-554-6804-0 (print)OAI: oai:DiVA.org:uu-7548DiVA, id: diva2:169707
Public defence
2007-03-16, Rudbeckssalen, Rudbeckslaboratoriet, Dag Hammarskjölds väg 20, Uppsala, 09:15
Opponent
Supervisors
Available from: 2007-02-23 Created: 2007-02-23 Last updated: 2013-06-20Bibliographically approved
List of papers
1. The exactness of left ventricular segmentation in cine magnetic resonance imaging and its impact on systolic function values
Open this publication in new window or tab >>The exactness of left ventricular segmentation in cine magnetic resonance imaging and its impact on systolic function values
Show others...
2007 (English)In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 48, no 3, p. 285-291Article in journal (Refereed) Published
Abstract [en]

Purpose: To evaluate the impact of exactness of the segmentation of the left ventricle (LV), using cine magnetic resonance imaging (MRI). Material and methods: Steady-state free-precession cine MRI was performed on 100 randomly selected subjects. Myocardial borders were outlined on short-axis images using three methods: method 1 was computer assisted, excluding papillary muscles from the left ventricular mass (LVM); method 2 was similar but included papillary muscles; and method 3 was manually traced including papillary muscles. LV end-systolic (ES) and end-diastolic (ED) masses and volumes, ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were calculated from these measurements. The difference between the ES and ED LVM was used to estimate the exactness of the methods. Results: Method 3 was the most exact, and method 1 was the least exact. The three methods generated differing EF, SV, and CO measurements. With an ES-ED LVM difference exceeding 20 g, the mean SV measurement error was 8.83.6 ml. Conclusion: Manual tracing proved more exact than computer-assisted quantification. Exactness had an impact on EF, SV, and CO measurements, and the ES-ED LVM difference can be used to identify assessments that would benefit from more exact segmentation.

Keywords
Adults, Cardiac, Heart, Left ventricle, MR imaging, Segmentation
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-17082 (URN)10.1080/02841850601182154 (DOI)000246336400009 ()17453498 (PubMedID)
Available from: 2008-06-16 Created: 2008-06-16 Last updated: 2017-12-08Bibliographically approved
2. Myocardial scars more frequent than expected - Magnetic resonance imaging detects potential risk group
Open this publication in new window or tab >>Myocardial scars more frequent than expected - Magnetic resonance imaging detects potential risk group
Show others...
2006 (English)In: Journal of the American College of Cardiology, ISSN 0735-1097, E-ISSN 1558-3597, Vol. 48, no 4, p. 765-771Article in journal (Refereed) Published
Abstract [en]

Objectives: The aim of this study was to investigate the prevalence of clinically recognized myocardial infarctions (RMIs) and unrecognized myocardial infarctions (UMIs) in 70-year-old subjects, assessed with magnetic resonance imaging (MRI), and to relate the findings to cardiac function and morbidity. Background: Late enhancement MRI identifies myocardial scars and thereby has the potential to detect UMI. Methods: Cardiac MRI was performed on 259 randomly chosen 70-year-old subjects. Late enhancement and cine sequences were acquired, and the ejection fraction and left ventricular (LV) mass were calculated. Late enhancement involving the subendocardial layer was considered to represent myocardial infarction (MI) scars, and their volumes were calculated. Information on cardiac morbidity and risk factors was collected from medical records and from a health examination. Subjects with MI scars, with or without a hospital diagnosis of MI were classified as RMI or UMI, respectively. Results: The images from 248 subjects (123 women, 125 men) were assessable. Myocardial infarction scars were found in 60 subjects (24.2%), in 49 of whom (19.8%) they were UMIs. The volumes of the UMIs were significantly smaller than those of the RMIs. There was an increased frequency of chest pain symptoms among the subjects with UMI or RMI compared with those without MI scars. Ejection fraction was significantly lower and LV mass significantly larger in the subjects with UMI or RMI than in those without MI scars. Conclusions: Unrecognized MI detected with MRI was more frequent than expected in 70-year-old subjects. The subjects displaying these UMIs may represent a previously unknown potential risk group for future cardiovascular events.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-95477 (URN)10.1016/j.jacc.2006.05.041 (DOI)000239771100014 ()16904547 (PubMedID)
Available from: 2007-02-23 Created: 2007-02-23 Last updated: 2017-12-14Bibliographically approved
3. Clinically unrecognized myocardial infarction detected at MR imaging may not be associated with atherosclerosis
Open this publication in new window or tab >>Clinically unrecognized myocardial infarction detected at MR imaging may not be associated with atherosclerosis
Show others...
2007 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 245, no 1, p. 103-110Article in journal (Refereed) Published
Abstract [en]

Purpose: To prospectively investigate whether there is support for the hypothesis that clinically unrecognized myocardial infarctions (UMIs) detected at magnetic resonance (MR) imaging have an atherosclerotic pathogenesis similar to that of recognized myocardial infarctions (RMIs).

Materials and Methods: After ethics committee approval and informed consent were obtained, gadolinium-enhanced whole-body MR angiography and late-enhancement MR imaging were performed in 248 randomly chosen 70-year-old subjects (123 women, 125 men). Imaging included the aorta and the carotid, renal, and lower limb arteries to the ankle, but not the coronary arteries. Subjects with myocardial infarction (MI) scars at late-enhancement MR imaging were classified as having RMI (n = 11) (those with a diagnosis of MI at the hospital) or UMI (n = 49) (those without a diagnosis of MI at the hospital). The presence of 50% or higher luminal narrowing in any vessel at whole-body MR angiography was considered to represent significant atherosclerosis. Intima-media thickness of the common carotid artery was measured with ultrasonography. C-reactive protein level was measured, and coronary heart disease risk was estimated. Observers were blinded to any previous results. The chi(2) test analysis of variance, and Bonferroni correction were used for statistical analyses.

Results: None of the measured parameters differed significantly between the group without MI scars and the UMI group, but parameters were significantly increased in the RMI group (P < .05) compared with those in the group without MI scars. Forty-two of 49 UMIs and nine of 11 RMIs were located within inferolateral segments of the left ventricle.

Conclusion: MR imaging-detected UMIs might have a different pathogenesis from that of RMIs or may have the same pathogenesis but may manifest at an earlier stage.

Keywords
CORONARY-ARTERY-DISEASE; INTIMA-MEDIA THICKNESS; CARDIOVASCULAR RISK-FACTORS; ST-SEGMENT ELEVATION; C-REACTIVE PROTEIN; MAGNETIC-RESONANCE; ASSESSMENT STRATEGIES; VULNERABLE PATIENT; HEART-DISEASE; CHEST-PAIN
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-95478 (URN)10.1148/radiol.2451061664 (DOI)000249577500013 ()
Available from: 2007-02-23 Created: 2007-02-23 Last updated: 2017-12-14Bibliographically approved
4. Increased collagen turnover in subjects with MRI-detected unrecognized myocardial infarction
Open this publication in new window or tab >>Increased collagen turnover in subjects with MRI-detected unrecognized myocardial infarction
Show others...
Manuscript (Other academic)
Identifiers
urn:nbn:se:uu:diva-95479 (URN)
Available from: 2007-02-23 Created: 2007-02-23 Last updated: 2010-01-13Bibliographically approved

Open Access in DiVA

fulltext(1903 kB)839 downloads
File information
File name FULLTEXT01.pdfFile size 1903 kBChecksum MD5
112696c6e6f987c33bd555d844d5195db438c47f05d9c54bbfac0fb99303b968e6d9e3e4
Type fulltextMimetype application/pdf
cover(537 kB)47 downloads
File information
File name COVER01.pdfFile size 537 kBChecksum MD5
b25089f03b791533cc706e35040f93f6fc7b18c0f402283710be12b1cd6c937c32f9d6de
Type coverMimetype application/pdf
Buy this publication >>

By organisation
Department of Oncology, Radiology and Clinical Immunology

Search outside of DiVA

GoogleGoogle Scholar
Total: 839 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1396 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf