Advisory Committee Chair
Gabriel Elgavish
Advisory Committee Members
Brigitta Brott
Jan Hollander
Tim Townes
Donald Twieg
Document Type
Dissertation
Date of Award
2007
Degree Name by School
Doctor of Philosophy (PhD) Heersink School of Medicine
Abstract
Ischemic heart disease is the leading cause of mortality in western societies. Treatment needs to be tailored for each individual, which requires accurate assessment of the underlying pathology. Magnetic Resonance Imaging (MRI) is a relatively young modality in the field of cardiovascular imaging, and boasts with the lack of harmful radiation, excellent soft tissue contrast, and high spatial-temporal resolution. The very foundation of the concept of MRI was the finding that pathology causes changes in the relaxation rates of tissues. Measurement of relaxation rates is more time consuming than generating simple signal intensity images weighted by the longitudinal or transverse relaxation properties of tissues. Thus, signal intensity has become more widely used in the clinic. Regarding the interpretation of images, conventional methods of delineating pathology either trace the borders (manually or automatically) of the pathology, or set a threshold above (or below) which all pixels are considered fully pathological or entirely healthy. In the present work, the main goal was to develop and validate novel methods of quantifying tissue changes per voxel, on a continuous scale, in the infarcted myocardium, to visualize and quantify tissue types such as necrosis, edema, or hemorrhage. iii The first two chapters focus on the generation of Percent Infarct Maps, quantifying the extent of non-viable tissue per voxel, based on longitudinal relaxation rates in canine reperfused myocardial infarction. In the first chapter an investigational contrast agent, Gd(ABE-DTTA), in the second, a presently clinically used contrast agent, Gd(DTPA), was administered. Triphenyltetrazolium-chloride-staining and microscopic histology were used for validation. The third chapter introduces two methods, the Percent Edema Mapping method, and the Tissue Characterization Mapping method. These methods exploit the changes in transverse relaxation rates due to edema, necrosis and hemorrhage. The fourth chapter proposes a method whereby measurement of post contrast longitudinal relaxation rates may be sped up utilizing an Equilibrium Signal Intensity Map acquired before administration of the agent. The aim of the fifth chapter is to characterize the phenomenological myocardial tissue kinetics of Gd(ABE-DTTA), used successfully for myocardial viability assessment in the first chapter.
Recommended Citation
Suranyi, Pal, "Relaxation Rate-Based Magnetic Resonance Imaging Quantification Of Myocardial Infarction" (2007). All ETDs from UAB. 3812.
https://digitalcommons.library.uab.edu/etd-collection/3812