Tierärztliche Hochschule Hannover

Summary
7 Summary
Ahrend, Liza K. (2013):
Evaluation of magnetic resonance spectroscopy techniques using a 3 Tesla
MRI Philips Achieva 3.0T-scanner to measure different metabolites in the
canine spinal cord in vivo
Magnetic resonance spectroscopy (MRS) measurement in the spinal cord is rarely
used in human, as well as in veterinary medicine. For several brain disorders, MRS is
an established method to investigate the underlying pathology in addition to routine
magnetic resonance imaging (MRI) examinations. However, the use of MRS in spinal
cord diseases is restricted due to magnetic field inhomogeneities induced by the
encompassing bone, the small diameter of the spinal cord, movement artifacts,
cerebrospinal fluid (CSF) pulsation within the central canal and contamination of the
voxel by the surrounding tissue. Despite these limitations, MRS is able to reveal
pathological changes invisible in conventional magnetic resonance imaging.
To prove the hypothesis that measurement of metabolites in the canine spinal cord is
feasible with MRS, 47 dogs undergoing routine magnetic resonance imaging
examination, were examined under general anesthesia in a 3 Tesla Philips Achieva
MRI-scanner. After routine MRI diagnostic to find structural abnormalities and to
place a voxel carefully, a PRESS-sequence was used for spectroscopic
measurements in normally appearing tissue. The dogs were divided into two groups,
independent of age, gender, underlying disease and weight. In 23 dogs the voxel
was placed in the brain and in the other 24 animals in the spinal cord. Every dog had
only one spectroscopic examination in one of the two localizations. Additionally, 2
different voxel sizes were used and compared. Voxel sizes containing less than 1ml
tissue were defined as small voxel and containing more than one milliliter as large
voxel. To compare the evaluated data, the same sequences were used to measure
well known metabolite concentrations in a round bottom flask phantom filled with a
nearly physiological solution of brain metabolites.
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