Digital Commons Network^™

Resting State Default-Mode Network Connectivity In Early Depression Using A Seed Region-Of-Interest Analysis: Decreased Connectivity With Caudate Nucleus., Robyn Bluhm, Peter Williamson, Ruth Lanius, Jean Theberge, Maria Densmore, Robert Bartha, Richard Neufeld, Elizabeth Osuch

Department of Medicine Publications

AIM: Reports on resting brain activity in healthy controls have described a default-mode network (DMN) and important differences in DMN connectivity have emerged for several psychiatric conditions. No study to date, however, has investigated resting-state DMN in relatively early depression before years of medication treatment. The objective of the present study was, therefore, to investigate the DMN in patients seeking help from specialized mental health services for the first time for symptoms of depression.

METHODS: Fourteen depressed subjects and 15 matched controls were scanned using 4-T functional magnetic resonance imaging while resting with eyes closed. All but one subject was …

Clinical Field-Strength Mri Of Amyloid Plaques Induced By Low-Level Cholesterol Feeding In Rabbits, John A. Ronald, Yuanxin Chen, Lisa Bernas, Hagen H. Kitzler, Kem A. Rogers, Robert A. Hegele, Brian K. Rutt

Robarts Imaging Publications

Two significant barriers have limited the development of effective treatment of Alzheimer’s disease. First, for many cases the aetiology is unknown and likely multi-factorial. Among these factors, hypercholesterolemia is a known risk predictor and has been linked to the formation of b-amyloid plaques, a pathological hallmark this disease. Second, standardized diagnostic tools are unable to definitively diagnose this disease prior to death; hence new diagnostic tools are urgently needed. Magnetic resonance imaging (MRI) using high field-strength scanners has shown promise for direct visualization of b-amyloid plaques, allowing in vivo longitudinal tracking of disease progression in mouse models. Here, we present …

Investigation, Design, And Integration Of Insert Gradient Coils In Magnetic Resonance Imaging, Rebecca E. Feldman

Digitized Theses

Diffusion-weighted magnetic resonance imaging utilizes the magnetic gradients of the system to de-phase protons undergoing diffusion with respect to the overall mag­ netization. Areas of the image with reduced signal when compared to an un-weighted image represent where protons have undergone diffusion. The stronger the gradient applied during diffusion-weighting, the larger the signal loss due to diffusion, and the larger the b-value differentiating the diffusion coefficients. However, the maximum gradient strength during image acquisition is limited by both the original strength of the signal and peripheral nerve stimulation.

Nerve stimulation is induced because the changing magnetic fields of the gradient …

Evaluation Of Cerebral Lateral Ventricular Enlargement Derived From Magnetic Resonance Imaging: A Candidate Biomarker Of Alzheimer Disease Progression In Vivo, Sean M. Nestor

Digitized Theses

Alzheimer disease (AD) is the most common form of dementia and has grievous mortality rates. Measuring brain volumes from structural magnetic resonance images (MRI) may be useful for illuminating disease progression. The goal of this thesis was to (1) help refine a novel technique used to segment the lateral cerebral ventricles from MRI, (2) validate this tool, and determine group-wise differences between normal elderly controls (NEC) and subjects with mild cognitive impairment (MCI) and AD and (3) determine the number of subjects necessary to detect a 20 percent change from the natural history of ventricular enlargement with respect to genotype. …