Tierärztliche Hochschule Hannover

Manuskript I
4.3.5 Statistics
The testing for normal distribution was performed by Shapiro-Wilk and the
Kolmogorov-Smirnov test as well as by the visual assessment of q-q-plots.
Furthermore, the Wilcoxon-Mann-Whitney-Test was used to evaluate a potential
significant difference of the metabolite concentration between brain and spinal cord.
Additionally, the chi-square-test was performed to determine the correlation of
reliable peaks and unreliable measurements between brain and spinal cord but also
small and large voxel. All data analyses were conducted with statistic program
package SAS®, version 9.2 (SAS Institute, Cary, NC). For all statistical tests we
attained an error probability of p < 0.05 as significant level.
4.4 Results
After MRI examination, all examined voxel were measured in apparently unaffected
tissue. Fortyseven dogs were included in the study. Of these, 23 had measurements
in the brain and 24 examinations in the spinal cord. Two dogs of each group were
excluded due to peaks which were not evaluable. The 21 measurements in the brain
were divided into 15 measurements with small voxel and six with large voxel. In the
22 examinations of the spinal cord 15 measurements were performed setting a small
voxel and seven with large voxel.
The concentrations of each metabolite could be defined in meq/L in normal
appearing neuronal tissue of spinal cord and brain (Fig. 2 and Tab. 1).
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