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Determining the longitudinal relaxation time ( T 1 ) of blood at 3.0 Tesla
Author(s) -
Lu Hanzhang,
Clingman Chekesha,
Golay Xavier,
van Zijl Peter C.M.
Publication year - 2004
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20178
Subject(s) - hematocrit , arterial spin labeling , blood flow , oxygenation , nuclear magnetic resonance , nuclear medicine , venous blood , arterial blood , relaxation (psychology) , hemodynamics , magnetic resonance imaging , medicine , cardiology , radiology , physics
It is important to determine the longitudinal relaxation time of blood for black blood imaging, as well as for quantifying blood flow by arterial spin labeling (ASL). In this study a circulation system was used to measure blood T 1 under physiological conditions at the new clinical field strength of 3.0T. It was found that 1/ T 1 in s −1 was linearly dependent ( P < 0.05) on hematocrit (Hct) within a normal range of 0.38–0.46. The relationships were 1/ T 1 = (0.52 ± 0.15) · Hct + (0.38 ± 0.06) and 1/ T 1 = (0.83 ± 0.07) · Hct + (0.28 ± 0.03) for arterial (oxygenation = 92% ± 7%) and venous blood (69% ± 8%), respectively, which led to estimated T 1 values of 1664 ± 14 ms (arterial) and 1584 ± 5 ms (venous) at a typical human Hct of 0.42. The temperature dependencies of blood T 1 were 22.3 ± 0.6 ms/°C and 19.8 ± 0.8 ms/°C for Hct values of 0.42 and 0.38, respectively. When a head coil transmit/receive setup was used, radiation damping caused a slight reduction (19 ms) of the measured T 1 values. Magn Reson Med 52:679–682, 2004. © 2004 Wiley‐Liss, Inc.