Lacking Lactate ??

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Lacking Lactate ??
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Lactate measurement at 3T

• How much do we gain from 3T? ? phantom
  experiments

144ms, 1.5T
288ms, 1.5T
144ms, 3T
288ms, 3T
? What has happened to the lactate at 144 ms at
3T?
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Lactate measurement at 3T
Lactate molecule
CH3 doublet at 1.31 ppm CH quartet at 4.10 ppm
CH3
weak coupling
CH
Large chemical shift displacements between CH3
(1.3ppm) and CH (4.1ppm) of lactate gt different
volumes selected signal loss of lactate
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Coupling evolution of Lactate
time
0 ms
72 ms
144 ms
216 ms
288 ms
J(Lac) 6.933 Hz
Govindaraju et al., NMR Biomed. 200013129-153
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Coupling evolution of Lactate
TE 144ms negative doublet
BW large enough ?
BW(180)
large signal loss due to signal cancellation!
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Lactate signal analysis at TE 144
The difference between inverted and upright CH3
signals, expressed as a fraction of the total
number of lactates within the CH3 PRESS box. A
value of 1.0 signifies perfect inversion. A
negative value signifies an overall positive
lactate peak at TE 144.
Rather than specify the PRESS box solely in terms
of refocusing (and excitation) pulse profiles,
instead over-prescribe the PRESS box and use
power-level-3 REST slabs with a negative gap to
actually define the edges.
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Gradient rephase required opt_ex_1
53 spredrex 15 fremex05 25
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