Showing papers by "Kenneth K. Kwong published in 1991"
TL;DR: Techniques for measuring cerebral blood volume have been validated in animal models and have recently been applied to human studies and extension of these techniques to the measurement of cerebral blood flow is presented.
Abstract: Contrast-enhanced magnetic resonance imaging of regional cerebral hemodynamics is discussed. Techniques for measuring cerebral blood volume (CBV) have been validated in animal models and have recently been applied to human studies. Factors affecting CBV measurement in pathologic tissue are addressed. Extension of these techniques to the measurement of cerebral blood flow is presented. © 1991 Academic Press, Inc.
285 citations
TL;DR: A CSF‐suppressed, inversion‐recovery (IR) single‐shot diffusion sequence was used to demonstrate that CSF makes a dominant contribution to the nonmonoexponential diffusion decay behavior observed in cortical gray matter brain tissue.
Abstract: A CSF-suppressed, inversion-recovery (IR) single-shot diffusion sequence was used to demonstrate that CSF makes a dominant contribution to the nonmonoexponential diffusion decay behavior observed in cortical gray matter brain tissue. © 1991 Academic Press, Inc.
123 citations
TL;DR: Cerebral blood flow was quantitatively mapped by monitoring the cerebral washout of H2 17O using rapid, single‐shot proton NMR imaging, and measured values for CBF ranged from 29 to 106 ml/min/100 g over a range of arterial pCO2.
Abstract: Cerebral blood flow was quantitatively mapped by monitoring the cerebral washout of H2(17)O using rapid, single-shot proton NMR imaging. H2(17)O acts as a freely diffusible contrast agent for proton imaging via its scalar-coupled term, enhancing T2 relaxation. Measured values for CBF ranged from 29 to 106 ml/min/100 g over a range of arterial pCO2 between 23 and 81 Torr.
65 citations
TL;DR: Magnetic resonance imaging with gadolinium‐diethylenetriaminepentaacetic acid complex (GdDTPA) as the contrast agent was used to image the aqueous chamber of the eye, and this method permits quantitative study of the aQueous flow.
Abstract: Magnetic resonance imaging with gadolinium-diethylenetriaminepentaacetic acid complex (GdDTPA) as the contrast agent was used to image the aqueous chamber of the eye. This method, in addition to providing spatial information, permits quantitative study of the aqueous flow. GdDTPA solution was applied either topically or intravenously, entering the anterior chamber via different pathways. The wash-in and wash-out of GdDTPA follow a two-compartment model which enables determination of the aqueous flow rate by multiplying the aqueous chamber volume by the wash-out rate constant. Rabbit eyes showed a flow rate of 1.5−2 μ1/min which was retarded by the systemic administration of acetazolamide ( Diamox ). © 1991 Academic Press, Inc.
19 citations
TL;DR: Topically applied H2 17O (10% enrichment) was used in magnetic resonance studies to quantify intraocular water dispersion in vivo and proton MR imaging of H217O dissipation from the aqueous chamber with clinical imagers, coupled with eyedrop application supported the topical data.
Abstract: Topically applied (eyedrop) H217O (10% enrichment) was used in magnetic resonance studies to quantify intraocular water dispersion in vivo The rate of H217O removed from the aqueous chamber is in the order of 01 ml/min/ml of tissue Similar results are obtained with either proton imaging or 17O spectroscopy Parallel experiments of direct injection of H217O into the aqueous chamber supported the topical data Proton MR imaging of H217O dissipation from the aqueous chamber with clinical imagers, coupled with eyedrop application suggerts clinical possibilites © 1991 Academic Press, Inc
14 citations
TL;DR: Surface coil NMR spectroscopy on D2O-treated eyes in vivo showed that the flow pattern was best described by a single exponential decay plus a constant, which suggests that the D2 O flow consisted of a flow component representing vascular circulation, and a reservoir-like component.
7 citations
TL;DR: Proton magnetic resonance imaging was tested in rabbits in vivo and the results suggest that this imaging method could provide a useful alternative to ultrasonography, especially in eyes with opaque media.
Abstract: The efficacy of proton magnetic resonance imaging in differentiating vitreous from C3F8 gas and silicone oil tamponades, and in detecting fresh hemorrhages and condensed vitreous was tested in rabbits in vivo. The results suggest that this imaging method could provide a useful alternative to ultrasonography, especially in eyes with opaque media.
6 citations