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Quantitative susceptibility mapping (QSM) based on gradient echo (GRE) magnetic resonance phase data is a novel technique for non-invasive assessment of magnetic tissue susceptibility differences. The method is expected to be an important means to determine iron distributions in vivo and may, thus, be instrumental for elucidating the physiological role of(More)
Quantitative magnetic susceptibility mapping (QSM) has recently been introduced to provide a novel quantitative and local MRI contrast. However, the anatomical contrast represented by in vivo susceptibility maps has not yet been compared systematically and comprehensively with gradient (recalled) echo (GRE) magnitude, frequency, and R(2)(*) images.(More)
To assess a magnetic resonance (MR) imaging method for depicting small veins in the brain, a three-dimensional, long echo time, gradient-echo sequence that depended on the paramagnetic property of deoxyhemoglobin was used. Veins with diameters smaller than a pixel were depicted. This MR imaging method is easy to implement and may prove helpful in the(More)
Quantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance phase images. It is commonly assumed that paramagnetic iron is the predominant source of susceptibility variations in gray matter as many studies have reported a(More)
Several gradient-echo fMRI blood oxygenation level-dependent (BOLD) effects are described in the literature: extravascular spin dephasing around capillaries and veins, intravascular phase changes, and transverse relaxation changes of blood. This work considers a series of tissue compartmentalized models incorporating each of these effects, and tries to(More)
A novel noninvasive magnetic resonance imaging (MRI) method was developed to determine in vivo blood oxygen saturation and its changes during motor cortex activation in small cerebral veins. Specifically, based on susceptibility measurements in the resting states, pial veins were found to have a mean oxygen saturation of Yrest=0.544+/-0.029 averaged over 14(More)
This paper reviews the recent development of a new high-resolution magnetic resonance imaging approach to visualizing small veins in the human brain with diameters in the sub-millimeter range, which is smaller than a voxel. It briefly introduces the physical background of the underlying bulk magnetic susceptibility effects, on which this approach is based,(More)
Diffusion-weighted imaging (DWI) techniques have shown potential to differentiate between benign and malignant neoplasms. However, the diagnostic significance of using DWI under routine conditions remains unclear. This study investigated the use of echo planar imaging (EPI) and half-Fourier acquired single-shot turbo spin echo (HASTE)-DWI with respect to(More)
Breathing carbogen (5% CO2 / 95% O2) dramatically increases cerebral blood flow (CBF), which induces a blood oxygenation level dependent (BOLD) related vascular signal change due to the concomitantly increased oxyhemoglobin concentration in the veins. However, carbogen often causes discomfort due to its forced strong and deep breathing which also may lead(More)
BACKGROUND AND PURPOSE MR gradient echo imaging is sensitive to the magnetic susceptibility of different tissue types. The purpose of this study was to investigate the diagnostic potential of MR phase imaging of the human brain. METHODS High-spatial-resolution, T2*-weighted, single-echo images were acquired in five volunteers and one patient with a brain(More)