Tierärztliche Hochschule Hannover

Manuskript I
Choline nearly exhibited the same concentration estimates in the spinal cord as in
the brain. Moreover, equal results were obtained assessing the concentration of N-
acetyl-aspartate, myo-inositol and creatine. The acquisition of lactate and glutamate
and glutamine displayed a higher concentration range in the spinal cord than in the
brain, in case of glutamate and glutamine the difference was significant (p = 0.0001;
Fig. 2 and Tab. 1). The metabolite concentration estimates in the spinal cord
revealed a larger range than detected in the brain.
Tab. 1: Range, quartile range and median of the concentration of different
metabolites measured in the canine brain and spinal cord using magnetic resonance
spectroscopy
Metabolite: Location: Range (x max – x min )
in meq/L
Quartile range (q 3 – q 1 )
in meq/L
Median in
meq/L
Cho brain 0.12 – 66.83 2.35 – 7.46 5.70
spinal cord 0.00 – 132.17 1.22 – 8.43 3.46
NAA brain 5.60 – 32.64 7.27 – 16.69 10.70
spinal cord 1.21 – 78.99 3.87 – 14.62 10.91
mI brain 0.32 – 476.05 2.51 – 10.01 5.15
spinal cord 0.00 – 198.47 1.26 – 18.54 8.99
Cr brain 2.55 – 168.53 6.47 – 18.18 15.95
spinal cord 0.00 – 323.62 4.97 – 36.63 20.20
Lac brain 1.06 – 39.42 10.15 – 28.68 16.16
spinal cord 0.00 – 399.58 1.65 – 60.55 3.73
Glx brain 0.00 – 1050.14 7.19 – 30.24 12.07
spinal cord 0.00 – 5086.99 25.43 – 600.87 96.89
Tab. 1: Shows the range, quartile range and median of the concentration of the
metabolites Cho (choline), NAA (N-acetyl-aspartate), mI (myo-Inositol), Cr (creatine),
Lac (lactate) and Glx (glutamate and glutamine). The concentrations are represented
in meq/L.
Figure 3 depicts spectra of the phantom (a) with a 7x7x7 mm 3 voxel at body
temperature in contrast to a voxel (5x7x25 mm 3 ) placed in the brainstem (b) of a dog.
Both voxel are defined as small voxel in the current study. Values that could not
definitely be allocated to a metabolite, for several reasons, are therefore evaluated as
unreliable. These unreliable values obtained with the small voxel positioned in the
brainstem are labeled by interrogation marks next to the metabolite name.
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