Tissue perfusion in humans studied by Fourier velocity distribution, line scan, and echo-planar imaging.
In tissue perfusion studies, FT velocity distribution imaging (VDI) intrinsically distinguishes signals from moving blood and volume-averaged tissue. Results in human thyroid gland, in vivo, using VDI line scan technique demonstrated separation of moving blood signal from glandular tissue, while VDI inner-volume echo-planar imaging of brain showed only CSF velocity above the image noise level. New alternating polarity gradient sequences which permit separation of diffusion and slow velocity are discussed. A novel method of 3D FT imaging (two spatial and one velocity dimension) combining inner-volume imaging and echo-planar imaging with velocity resolution of 0.15 mm/s per pixel is demonstrated. A novel graphical method of calculation and display of diffusion dependence in pulsed gradient sequences is presented.
Feinberg
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DA
Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts 02115.
Jakab
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PD
D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology*; D002555:Cerebrospinal Fluid / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D005583:Fourier Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008961:Models, Structural; D013961:Thyroid Gland / Q000033:anatomy & histology*