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We investigated the biophysical mechanism of low-frequency drift in blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) (0.00-0.01 Hz), by exploring its spatial distribution, dependence on imaging parameters, and relationship with task-induced brain activation. Cardiac and respiratory signals were concurrently recorded during(More)
Formation of operational neural networks is one of the most significant accomplishments of human fetal brain growth. Recent advances in functional magnetic resonance imaging (fMRI) have made it possible to obtain information about brain function during fetal development. Specifically, resting-state fMRI and novel signal covariation approaches have opened up(More)
The development of functional brain magnetic resonance imaging (fMRI) has been a boon for neuroscientists and radiologists alike. It provides for fundamental information on brain function and better diagnostic tools to study disease. In this paper, we will review some of the early concepts in high resolution gradient echo imaging with a particular emphasis(More)
BACKGROUND Investigations into the mechanism of diffuse retinal edema in diabetic subjects have been limited by a lack of animal models and techniques that co-localized retinal thickness and hydration in vivo. In this study we test the hypothesis that a previously reported supernormal central retinal thickness on MRI measured in experimental diabetic(More)
BACKGROUND Hepatic cirrhosis is a common pathway of progressive liver destruction from multiple causes. Iron uptake can occur within the hepatic parenchyma or within the various nodules that form in a cirrhotic liver, termed siderotic nodules. Siderotic nodule formation has been shown to correlate with inflammatory activity, and while the relationship(More)
PURPOSE To demonstrate the mapping of structures with high susceptibility values, such as the sinuses, bones and teeth, using short echo times. METHODS Four in vivo datasets were collected with a gradient-echo sequence (TE1 = 2.5 ms, TE2 = 5 ms and TE3 = 7.5 ms). Complex division was performed to remove the phase offset term and generate the phase at TE =(More)
PURPOSE To evaluate the capability of a dual-cooling technique in suppressing motion artifact and to evaluate the feasibility of the noninvasive muscle fibers tracking using DTI during chick embryonic development. MATERIALS AND METHODS Fifteen eggs were divided into three groups of 5 eggs each (one group for each imaging sequence), and eggs were imaged(More)
INTRODUCTION The piriform cortex and cortical amygdala (PCA) and the orbitofrontal cortex (OFC) are considered olfactory-related brain regions. This study aims to elucidate the normal volumes of PCA and OFC of each age groups (20.0-70.0 year old), and whether the volumes of PCA and OFC decline with increasing age and diminishing olfactory function. (More)
For more than a decade, turbo spin echo (TSE) pulse sequences have been suggested as an alternative to echo planar imaging (EPI) sequences for fMRI studies. Recent development in parallel imaging has renewed the interest in developing more robust TSE sequences for fMRI. In this study, a modified half Fourier acquisition single-shot TSE (mHASTE) sequence has(More)
Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Diffusion tensor imaging (DTI), based on the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Yet embryonic motion degrades the in vivo acquisition of long-duration DTI. We used a dual-cooling technique to avoid motion(More)