Intermolecular zero-quantum coherence detection for in vivo MR-spectroscopy [Elektronische Ressource] / vorgelegt von Dávid Zsolt Balla

David Klein

Sujets

• Physik

Informations

• Publié par: julius-maximilians-universitat_wurzburg
• Publié le: 01 janvier 2009
• Nombre de lectures: 19
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

Intermolecular zero-quantum coherence detection
for in vivo MR spectroscopy


Dissertation zur Erlangung
des naturwissenschaftlichen Doktorgrades
der Bayerischen Julius-Maximilians-Universität
Würzburg




vorgelegt von
Dávid Zsolt Balla
aus Oradea

Würzburg, 2009

2











Eingereicht am: 22. Januar 2009
bei der Fakultät für Physik und Astronomie

1. Gutachter: Prof. Dr. Peter Jakob
2. rof. Dr. Cornelius Faber
3. Gutachter:

1. Prüfer: Prof. Dr. Peter Jakob
2. Prüfer: Prof. Dr. Cornelius Faber
3. Prüfer: Prof. Dr. Georg Reents
im Promotionskolloquium

Tag des Promotionskolloquiums: 28. August 2009
Doktorurkunde ausgehändigt am:

Introduction 3
TABLE OF CONTENTS
INTERMOLECULAR ZERO-QUANTUM COHERENCE DETECTION FOR IN VIVO MR
SPECTROSCOPY................................................................................................................................................. 1
1. INTRODUCTION ............................................................................................................................................. 6
2. BASIC PRINCIPLES OF NMR....................................................................................................................... 8
2.1 THE ZEEMAN INTERACTION........................................................................................................................... 9
2.2 INTERACTION WITH AN OSCILLATING RF-FIELD ............................................................................................ 9
2.3 INTERNAL SPIN INTERACTIONS..................................................................................................................... 10
2.3.1 Chemical shift ..................................................................................................................................... 10
2.3.2 Direct dipolar interaction ................................................................................................................... 11
2.4 SPIN DENSITY OPERATOR ............................................................................................................................. 11
2.4.1 Product operator formalism................. 12
2.4.2 Magnetization ..................................................................................................................................... 13
2.4.3 The Liouville – von Neumann equation .............................................................................................. 15
2.5 MAGNETIZATION DYNAMICS ....................................................................................................................... 15
3. INTERMOLECULAR MULTIPLE-QUANTUM COHERENCE NMR SPECTROSCOPY ................. 17
3.1 THE QUANTUM PICTURE OF IZQC-SIGNAL FORMATION ............................................................................... 18
3.1.1 Spectral patterns ................................................................................................................................. 21
3.2 THE DISTANT DIPOLAR FIELD (DDF)............................................................................................................ 22
3.3 RESOLUTION ENHANCEMENT 24
3.4 SIGNAL EVOLUTION AND SPECTRAL ANALYSIS ............................................................................................ 25
4. METHOD DEVELOPMENT FOR IN VIVO IZQC-SPECTROSCOPY .................................................. 29
4.1 SELECTIVE HOMOGENIZED (SEL-HOMOGENIZED)............................................................................ 29
4.1.1 Theoretical analysis of SEL-HOMOGENIZED .................................................................................. 29
4.1.2 Optimal acquisition window for SEL-HOMOGENIZED .................................................................... 32
4.1.3 Experimental evaluation of SEL-HOMOGENIZED 34
4.1.3.1 Materials and methods...................................................................................................................................34
4.1.3.2 Results...........................................................................................................................................................34
4.2 WATER SUPPRESSION (WS) ......................................................................................................................... 36
4 Introduction
4.2.1 Optimization of WS efficiency at a high-resolution 9.4 T NMR spectrometer.....................................36
4.2.2 Water suppression at a 17.6 T small animal NMR microimager ........................................................39
4.3 SINGLE VOXEL LOCALIZATION.....................................................................................................................41
4.3.1 Localization within the HOMOGENIZED sequence (S1) ...................................................................41
4.3.2 Localization of the magnetization prior to a global HOMOGENIZED (S2).......................................43
4.3.3 Localization of detectable signal immediately prior to acquisition (S3).............................................44
4.3.4 The limits of localization efficiency of S1 and S2................................................................................45
4.3.4 Experimental comparison of localization techniques in a phantom....................................................46
4.3.4.1 Materials and methods .................................................................................................................................. 46
4.3.4.2 Results .......................................................................................................................................................... 46
4.3.5 Avoiding the chemical shift displacement artefact with S1 and S2 .....................................................48
5. IN VIVO APPLICATIONS OF LOCALIZED IZQC MRS.........................................................................50
5.1 EXPERIMENTAL HARDWARE AND ANIMAL PREPARATION.............................................................................50
5.1.1 Materials for in vivo experiments........................................................................................................50
5.1.2 Animal handling..................................................................................................................................51
5.2 VALIDATION OF SINGLE-VOXEL IZQC MRS IN THE RODENT BRAIN.............................................................51
5.2.1 Acquisition parameters and processing ..............................................................................................51
5.2.2 Results .................................................................................................................................................53
5.3 FEASIBILITY OF CONVENTIONAL AND IZQC MRS IN THE RAT SPINAL CORD AT 17.6 T 54
5.3.1 Materials and Methods........................................................................................................................54
5.3.2 Results...............................56
5.3.2.1 Conventional MRS ....................................................................................................................................... 56
5.3.2.2 i ZQC spectroscopy ..................................................................................................................................... 58
5.4 IZQC MRS IN TUMORS IN VIVO ..................................................................................................................59
5.4.1 Experimental details............................................................................................................................60
5.4.2 Results...............................61
6. IZQC-MRS IN PRESENCE OF LOCAL DIPOLE FIELDS .....................................................................63
6.1 MAXIMUM LOCAL DIPOLE FIELDS FOR RESOLUTION ENHANCEMENT............................................................63
6.1.1 Theory .................................................................................................................................................63
6.1.2 Numerical simulations.........................................................................................................................65
6.1.2.1 Simulation algorithm .................................................................................................................................... 65
Introduction 5
6.1.2.2 Simulation parameters...................................................................................................................................66
6.1.2.3 Analysis of the spectra...................................................................................................................................67
6.1.2.4 Validity assessment ....................................................................................................70
6.1.2.5 Tolerance of digitization error in simulations................................................................................................72
6.1.2.6 Results: The impact of B on linewidths and peak intensities .....................................................................74 dip
6.1.2 Exp