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The efficiency of adiabatic inversion for perfusion imaging by arterial spin labeling
Author(s) -
Maccotta Luigi,
Detre John A.,
Alsop David C.
Publication year - 1997
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199706/08)10:4/5<216::aid-nbm468>3.0.co;2-u
Subject(s) - adiabatic process , laminar flow , spins , arterial spin labeling , inversion (geology) , blood flow , perfusion , computational physics , nuclear magnetic resonance , materials science , chemistry , physics , mechanics , thermodynamics , geology , condensed matter physics , radiology , medicine , paleontology , structural basin
Abstract Velocity‐driven adiabatic inversion is an attractive method for labeling arterial blood spins for quantitative perfusion imaging. To quantify perfusion and to optimize experimental parameters, an accurate estimate of labeling efficiency is required. We present theoretical and numerical methods to calculate the labeling efficiency over a wide range of experimental and physiologic parameters. The results are compared to experimental measurements in vivo . Inversion efficiency was found to be higher than previously assumed and relatively insensitive to flow velocity and the amplitude of the RF irradiation used for inversion. Assuming laminar flow, labeling efficiencies of greater than 90% are easily obtainable over a broad range of flow velocities. For applications where RF power deposition is a limiting factor such as at high field strengths, labeling efficiency can be maintained by reducing the labeling gradient. These results further illustrate the capability of adiabatic inversion to effectively label flowing blood. © 1997 John Wiley & Sons, Ltd.