Improved Strain ENCoded (SENC) Cardiac MR Measurements and Composite SENC Image Segmentation / Abdullah Gaafar AbdelMotaal Mohamed

Supervisor: Nael Osman

Thesis (M.A.)—Nile University, Egypt, 2010 .

"Includes bibliographical references"

Contents:
Table of Contents
1. INTRODUCTION ..................................................................................................... 9
1.1 PURPOSE ................................................................................................................... 9
1.2 BACKGROUND ......................................................................................................... 9
1.2.1 STRUCTURE AND FUNCTION OF THE HEART ..................................... 9
1.2.2 DETECTING CARDIAC DISEASE ............................................................. 12
1.3 LITERATURE REVIEW ......................................................................................... 12
1.3.1 CARDIAC MR ................................................................................................ 14
1.3.1.1 BENEFITS AND RISKS OF CARDIAC MRI .......................................... 16
1.4 OVERVIEW OF DISSERTATION ........................................................................ 16
1.4.1 SUMMARY OF CONTRIBUTION .............................................................. 17
1.4.2 PREVIOUS PUBLICATIONS ....................................................................... 17
1.4.3 ORGANIZATION ........................................................................................... 17
2. STRAIN ENCODED CARDIAC MR ............................................... 18
2.1 SENC IMAGING ..................................................................................................... 18
2.2 DELAYED ENHANCEMENT IMAGING ............................................................ 21
2.3 COMPOSITE-SENC IMAGING ............................................................................ 22
3. SENC ANATOMY IMAGE ENHANCEMENT .............................. 24
3.1 THEORY .................................................................................................................. 24
3.2 EXPERIMENTS AND RESULTS .......................................................................... 26
3.3 DISCUSSION AND CONCLUSION ...................................................................... 30
4. IMPROVED STRAIN MEASURING USING F-SENC CARDIAC MR .... 31
4.1 INTRODUCTION .................................................................................................... 31
4.2 THEORY ................................................................................................................... 32
4.2.1 NON-INTERLEAVING ACQUISITION ..................................................... 32
4.2.2 INTERLEAVING ACQUISITION ............................................................... 33
4.2.3 INTERLEAVING BASE ERROR IN STRAIN MEASUREMENTS ........ 35
4.2.4 CORRECTION OF INTERLEAVING ERROR ......................................... 36
6
6
4.3 EXPERIMENTS ....................................................................................................... 38
4.3.1 NUMERICAL EXPERIMENTS .................................................................... 38
4.3.2 REAL DATA ................................................................................................... 39
4.4 RESULTS .................................................................................................................. 39
4.4.1 SIMULATED IMAGES .................................................................................. 39
4.4.2 REAL IMAGES ............................................................................................... 39
4.5 DISCUSSION AND CONCLUSION ...................................................................... 43
5. DIFFERENT REGION IDENTIFICATION IN COMPOSITE STRAIN ENCODED IMAGES ........................................................................................................ 44
5.1 INTRODUCTION .................................................................................................... 44
5.2 PROPOSED SYSTEMS ........................................................................................... 45
5.2.1 ONE-STAGE CLASSIFIER .......................................................................... 45
5.2.2 TWO-STAGE CLASSIFIER ......................................................................... 46
5.3 FUZZY C-MEANS ................................................................................................... 46
5.4 EXPERMINTAL RESULT ..................................................................................... 46
5.4.1 ONE-STAGE CLASSIFIER .......................................................................... 46
5.4.1.1 SIMULATED DATA .......................................................................... 46
5.4.1.2 REAL DATA ....................................................................................... 46
5.4.2 TWO-STAGE CLASSIFIER ......................................................................... 46
5.4.2.1 REAL DATA ....................................................................................... 46
5.4.2.2 SIMULATED DATA .......................................................................... 46
5.4.2.3 QUANTITATIVR ANALYSIS ......................................................... 46
5.5 DISCUSSION AND CONCLUSION ...................................................................... 56
BIBLIOGRAPHY

Abstract:
Cardiovascular magnetic resonance imaging is an active field of research aimed at using magnetic resonance imaging (MRI) to study the anatomy and function of the heart and the vascular system in vivo. Strain measurements during the cardiac motion give an indication for the heart function and they are useful indices of myocardial health. Several imaging techniques are used to measure the longitudinal, radial and circumferential strains of the heart. Recently, Strain Encoded (SENC) imaging technique, which directly encodes the regional strain into the acquired images, has been proposed. Using this technique a dense estimate of longitudinal strain on the short-axis view or circumferential strain on the longitudinal axis view can be measured, which can be used in quantifying regional function of heart. This can be useful for determining viability of the heart by stress test. Besides, a full anatomical detail for the heart and the surrounding tissues can be obtained. Unfortunately, the anatomy image suffers from low contrast to noise ratio. Also recently fast acquisition techniques have been proposed, interleaving acquisition, to shorten the acquisition time of the two tuned images by 50%, but it suffers from errors in the strain calculations due to inter-tunings motion of the heart. In this dissertation, enhancements in anatomy images and improved strain calculations are proposed. The results show an improvement in the contrast to noise ratio and strain calculations so as to relax the imaging constraints on spatial and temporal resolutions and improve image quality.
Different heart tissue identification is important for therapeutic decision-making in patients with myocardial infarction (MI), this provides physicians with a better clinical decision-making tool. Composite Strain Encoding (C-SENC) is an MRI acquisition technique that is used to acquire cardiac tissue viability and contractility images. It combines the use of black-blood delayed-enhancement (DE) imaging to identify the infracted (dead) tissue inside the heart muscle and the ability to image myocardial deformation from the strain-encoding (SENC) imaging technique. In this dissertation also, we proposed different approaches to identify the different heart tissues and the background regions in the C-SENC images. The results show that the applied techniques are able to identify the different regions in the image with a high accuracy.

Text in English, abstracts in English.