Medicine and Health Sciences Commons^™

Mri Relaxation Rates: A Quantitative Approach To Track Tumour Cells Expressing Maga, Anindita Sengupta

Electronic Thesis and Dissertation Repository

Using magnetic resonance imaging, relaxation rate measurements were

performed in cancer cells overexpressing a magnetotactic bacterial gene, MagA.

Measurements of magnetic resonance relaxation rates in this expression

system is important for optimizing cell detection and specificity, for developing

quantification methods, and for refinement of gene-based iron contrast using

magnetosome associated genes. We measured the total transverse

relaxation rate (R2^*), its irreversible and reversible components (R2 and R2^′,

respectively) and the longitudinal relaxation rate (R1) in MDA-MB-435 tumor cells.

Clonal lines overexpressing MagA were cultured in the presence and absence of

iron supplementation, and mounted in a …

Quantitative Susceptibility Imaging Of Tissue Microstructure Using Ultra-High Field Mri, David A. Rudko

Electronic Thesis and Dissertation Repository

This thesis has used ultra-high field (UHF) magnetic resonance imaging (MRI) to investigate the fundamental relationships between tissue microstructure and such susceptibility-based contrast parameters as the apparent transverse relaxation rate (R₂^*), the local Larmor frequency shift (LFS) and quantitative volume magnetic susceptibility (QS). The interaction of magnetic fields with biological tissues results in shifts in the LFS which can be used to distinguish underlying cellular architecture. The LFS is also linked to the relaxation properties of tissues in a gradient echo MRI sequence. Equally relevant, histological analysis has identified iron and myelin as two major sources of …