Evidencing different neurochemical profiles between thalamic nuclei using high resolution 2D-PRESS semi-LASER (1)H-MRSI at 7 T
Résumé
OBJECTIVE: To demonstrate that high resolution (1)H semi-LASER MRSI acquired at 7 T permits discrimination of metabolic patterns of different thalamic nuclei. MATERIALS AND METHODS: Thirteen right-handed healthy volunteers were explored at 7 T using a high-resolution 2D-semi-LASER (1)H-MRSI sequence to determine the relative levels of N-Acetyl Aspartate (NAA), choline (Cho) and creatine-phosphocreatine (Cr) in eight VOIs (volume \textless0.3 ml) centered on four different thalamic nuclei located on the Oxford thalamic connectivity atlas. Post-processing was done using the CSIAPO software. Chemical shift displacement of metabolites was evaluated on a phantom and correction factors were applied to in vivo data. RESULTS: The global assessment (ANOVA p \textless 0.05) of the neurochemical profiles (NAA, Cho and Cr levels) with thalamic nuclei and hemispheres as factors showed a significant global effect (F = 11.98, p \textless 0.0001), with significant effect of nucleus type (p \textless 0.0001) and hemisphere (p \textless 0.0001). Post hoc analyses showed differences in neurochemical profiles between the left and the right hemisphere (p \textless 0.05), and differences in neurochemical profiles between nuclei within each hemisphere (p \textless 0.05). CONCLUSION: For the first time, using high resolution 2D-PRESS semi-LASER (1)H-MRSI acquired at 7 T, we demonstrated that the neurochemical profiles were different between thalamic nuclei, and that these profiles were dependent on the brain hemisphere.