Learn More
High resolution functional MRI (fMRI) experiments were performed in human visual cortex at 0.5, 1.5, and 4 T to determine the blood oxygenation level dependent (BOLD) field strength response within regions of obvious venous vessels and cortical gray matter ("tissue"). T2*-weighted FLASH images were collected in single- and multi-echo mode and used to(More)
The driven-equilibrium single-pulse observation of T(1) (DESPOT1) and T(2) (DESPOT2) are rapid, accurate, and precise methods for voxelwise determination of the longitudinal and transverse relaxation times. A limitation of the methods, however, is the inherent assumption of single-component relaxation. In a variety of biological tissues, in particular human(More)
Variations in the intrinsic T(1) and T(2) relaxation times have been implicated in numerous neurologic conditions. Unfortunately, the low resolution and long imaging time associated with conventional methods have prevented T(1) and T(2) mapping from becoming part of routine clinical evaluation. In this study, the clinical applicability of the DESPOT1 and(More)
A novel, fully 3D, high-resolution T(1) and T(2) relaxation time mapping method is presented. The method is based on steady-state imaging with T(1) and T(2) information derived from either spoiling or fully refocusing the transverse magnetization following each excitation pulse. T(1) is extracted from a pair of spoiled gradient recalled echo (SPGR) images(More)
PURPOSE The precise role played by hemodynamics, particularly wall shear stress, in the development and progression of vascular disease remains unclear, in large part because of a lack of in vivo studies with humans. Although technical challenges remain for noninvasively imaging wall shear stresses in humans, vascular anatomy can be imaged with sufficiently(More)
In the current work we demonstrate, for the first time, that single cells can be detected in mouse brain in vivo using magnetic resonance imaging (MRI). Cells were labeled with superparamagnetic iron oxide nanoparticles and injected into the circulation of mice. Individual cells trapped within the microcirculation of the brain could be visualized with(More)
The authors present a unique application of polyvinyl alcohol (PVA) cryogel as an anthropomorphic, elastic, vascular phantom material that can be used in MR imaging. The composition consists of two nontoxic ingredients: water and PVA. The biomechanical and MR properties can be adjusted to be similar to those of excised porcine aortas by varying the number(More)
Magnetization transfer and multicomponent T2 imaging techniques were implemented to study guinea pig in vivo. A chronic-progressive model of experimental allergic encephalomyelitis (EAE) was produced, and the inflammatory component of the disease was manipulated using antibodies against integrin. The magnetization transfer ratio (MTR) and T2 relaxation(More)
A thorough understanding of the relationship between local hemodynamics and plaque progression has been hindered by an inability to prospectively monitor these factors in vivo in humans. In this study a novel approach for noninvasively reconstructing artery wall thickness and local hemodynamics at the human carotid bifurcation is presented.(More)
The design and operation of a detunable shielded hybrid birdcage RF head coil optimized for human brain imaging at 170 MHz is presented. A high duty-cycle and rapid-switching decoupling scheme that allows uniform RF transmission with the head coil and reception with a surface coil within the volume of the head coil is also demonstrated. In addition, the(More)