May 20, 2005 - MRI systems with respiratory navigator guided sequences reduce the ...... Mitchell, S.C., Bosch, J.G., Lelieveldt, B.P., van der Geest, R.J., Reiber ...
Helsinki Medical Imaging Center Helsinki University Central Hospital University of Helsinki Helsinki, Finland
ASSESSMENT OF CARDIAC FUNCTION WITH MAGNETIC RESONANCE IMAGING AND A THREE-DIMENSIONAL SEGMENTATION METHOD
Description of Mulibrey nanism cardiopathy and effects of endurance training on cardiac function
Sari Kivistö Academic dissertation To be presented, with the assent of the Medical Faculty of the University of Helsinki, for public examination in Lecture Room 12, Main building of the University of Helsinki, on the 20th of May, 2005, at 12 noon. Helsinki 2005
Supervisors Docent Kirsi Lauerma and Docent Pauli Hekali Helsinki Medical Imaging Center University of Helsinki Reviewers Docent Johanna Kuusisto Department of Cardiology University of Kuopio and Professor Jaakko Hartiala Department of Clinical Physiology and Nuclear Medicine University of Turku Opponent Docent Pekka Niemi Department of Diagnostic Radiology University of Turku
ISBN 952-91-8614-2 (paperback) ISBN 952-10-2431-3 (PDF) Helsinki University Printing House Helsinki 2005
To Jaakko and Jussi…
TABLE OF CONTENTS 1. ABSTRACT .....................................................................................................................6 2. LIST OF ORIGINAL PUBLICATIONS.............................................................................8 3. LIST OF ABBREVIATIONS ............................................................................................9 4. INTRODUCTION ...........................................................................................................10 5. REVIEW OF THE LITERATURE ...................................................................................12 5.1. BASIC PRINCIPLES OF CARDIAC MAGNETIC RESONANCE IMAGING............................................... 12 5.1.1. Signal on magnetic resonance images ................................................................................................................ 12 5.1.2. Cardiac triggering ............................................................................................................................................... 13 5.1.3. Gradient echo cine imaging ................................................................................................................................ 14 5.1.4. Fast imaging with steady-state free precession technique .................................................................................. 15 5.1.5. Phase contrast or velocity-encoded cine techniques ........................................................................................... 16 5.1.6. Myocardial tagging ............................................................................................................................................. 20 5.1.7. Spin echo imaging .............................................................................................................................................. 20 5.2. MAGNETIC RESONANCE IMAGE ANALYSIS ............................................................................................... 23 5.2.1. Cine magnetic resonance image analysis............................................................................................................ 24 5.2.2. Phase contrast or velocity-encoded cine image analysis..................................................................................... 29 5.2.3. Myocardial tagging data analysis........................................................................................................................ 29 5.2.4. Spin echo image analysis.................................................................................................................................... 30 5.3. MAGNETIC RESONANCE IMAGING OF DIASTOLIC FUNCTION ........................................................... 33 5.3.1. Normal ventricular diastolic function ................................................................................................................. 33 5.3.2. Pathophysiology of diastolic dysfunction ........................................................................................................... 36 5.3.3. Diseases causing diastolic dysfunction .............................................................................................................. 37 5.3.3.1. Left ventricular hypertrophy ........................................................................................................................ 37 5.3.3.2. Restrictive cardiomyopathy ......................................................................................................................... 38 5.3.3.3. Pericardial effusions or constriction ............................................................................................................ 38 5.3.3.4. Mulibrey nanism cardiopathy ...................................................................................................................... 39 5.3.4. Left ventricular adaptation to endurance training ............................................................................................... 40 5.3.5. Magnetic resonance imaging techniques for assessment of diastolic function ................................................... 41
6. AIMS OF THE STUDY...................................................................................................44 7. METHODS.....................................................................................................................45 7.1. SUBJECTS ............................................................................................................................................................... 45 7.1.1. Assessment of Mulibrey nanism cardiopathy with magnetic resonance imaging (I, II) ..................................... 45 7.1.2. Assessment of the effect of endurance training on left ventricular function (III) ............................................... 46 7.1.3. Three-dimensional segmentation model for the heart (IV)................................................................................. 47 7.2. MAGNETIC RESONANCE IMAGING PROTOCOLS ..................................................................................... 47 7.2.1. Assessment of Mulibrey nanism cardiopathy with magnetic resonance imaging (I, II) ..................................... 47 7.2.2. Assessment of the effect of endurance training on left ventricular function (III) ............................................... 48 7.2.3. Three-dimensional segmentation model for the heart (IV)................................................................................. 49 7.3. MAGNETIC RESONANCE IMAGING ANALYSIS .......................................................................................... 50 4
7.3.1. Assessment of Mulibrey nanism cardiopathy with magnetic resonance imaging (I, II) ..................................... 50 7.3.2. Assessment of the effect of endurance training on left ventricular function (III) ............................................... 51 7.3.3. Three-dimensional segmentation model for the heart (IV)................................................................................. 52 7.4. STATISTICAL ANALYSIS ................................................................................................................................... 56
8. RESULTS ......................................................................................................................58 8.1. Assessment of Mulibrey nanism cardiopathy with magnetic resonance imaging (I, II)................................... 58 8.2. Assessment of the effect of endurance training on left ventricular function (III) .............................................. 63 8.3. Three-dimensional segmentation model for the heart (IV).................................................................................. 68
9. DISCUSSION ................................................................................................................70 9.1. Assessment of Mulibrey nanism cardiopathy with magnetic resonance imaging (I, II).................................... 70 9.2. Assessment of the effect of endurance training on left ventricular function (III) .............................................. 72 9.3. Three-dimensional segmentation model for the heart (IV).................................................................................. 75
10. CONCLUSIONS ..........................................................................................................77 11. ACKNOWLEDGEMENTS ...........................................................................................78 12. REFERENCES ............................................................................................................80
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ABSTRACT The general purpose of this work was to evaluate the capacity of magnetic resonance imaging (MRI) for assessing cardiac function, particularly diastolic function. Study objectives Studies I and II: To describe characteristic features of Mulibrey nanism (MUL) with cardiac MRI. To assess volumes of all cardiac chambers, thickness of the pericardium and left ventricular (LV) mass, and to differentiate between constrictive pericarditis and restrictive cardiomyopathy. Study III: To assess the effect of endurance training on the early diastolic global and regional LV myocardial relaxation and systolic myocardial function with mitral flow velocity mapping, myocardial four-chamber tagging and cine MRI. Study IV: To describe an automated three-dimensional (3-D) segmentation method for all four cardiac chambers. Methods We examined 31 MUL patients and 16 controls to describe MUL cardiopathy (I, II). In addition, we investigated 14 subjects before and after a three-month training period to describe the effectiveness of endurance training on LV function (III). We combined the segmentation results of 25 subjects; 16 subjects from Study III ( =14 subjects+2 excluded subjects who underwent only one MRI) and 9 control subjects from Study II to build a statistical atlas of cardiac chambers, thus providing the basis for automated segmentation tools (IV). MRI studies were approved by the Human Research Committee of Helsinki University Central Hospital and performed at Helsinki Medical Imaging Center with a 1.5 T magnetic resonance scanner. In Studies I and II, the volumes and functions of all four cardiac chambers were assessed. In Study III, LV function was evaluated with mitral flow velocity mapping, myocardial four-chamber tagging, and cine MRI.
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Results In Studies I and II, the thickness of the pericardium was normal (
