| Anterior to posterior hippocampal MRS metabolite difference is mainly a partial volume effect. | |
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MedLine Citation:
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PMID: 20201639 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: The concentration of N-acetylaspartate (NAA) in hippocampus, as measured with magnetic resonance spectroscopy (MRS), and the ratio of NAA/(choline (Cho) + creatine (Cr)) are valuable tools in the lateralization of temporal lobe epilepsy (TLE). MRS of hippocampus is also increasingly used to study certain psychiatric and degenerative diseases. However, the reliability of such measurements of hippocampus has been questioned. PURPOSE: To re-evaluate MRS imaging data from prior control subjects with regard to variation of metabolite concentrations in hippocampus from anterior to posterior and the partial volume (R)contribution to the measurements from adjacent tissue. MATERIAL AND METHODS: Twelve healthy subjects, mean age 33 years, were studied with MRS imaging. The measurement volume was angled along the temporal horns and metabolite concentration images were reconstructed at the MR system. Regions of interest (ROIs) in the anterior, medial, and posterior parts of both hippocampi were evaluated. Signal normalization to the total MRS signal from all ROIs permitted pooling of individual data with different and unknown signal scaling. One subject was re-examined with a high resolution three-dimensional (3D) volume of the brain for evaluation of partial volumes in the MRS examination. RESULTS: Overall, there were significantly lower concentrations of NAA in the anterior parts, and of (Cho+Cr) in the posterior parts, while the NAA/(Cho+Cr) ratio in the posterior parts of the mesial temporal lobes was significantly higher. Hippocampus accounted for one-half, one-third, and one-quarter of the anterior, middle, and posterior ROIs, respectively. The NAA/(Cho+Cr) ratio thus showed a reverse relationship to the relative volume of hippocampal tissue within the ROI. CONCLUSION: Metabolite concentrations in the mesial temporal lobe obtained with MRS imaging represent the mean value of hippocampus and a considerable amount of adjacent tissue. To assess the hippocampus alone, an actual voxel well below 1 cm(3) and a sub-centimeter slice thickness are required. |
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Authors:
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G?ran Starck; Barbro Vkhoff-Baaz; Maria Ljungberg; Kristina Malmgren; Eva Forssell-Aronsson; Lars J?nsson; Sven Ekholm |
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Publication Detail:
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Type: Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Acta radiologica (Stockholm, Sweden : 1987) Volume: 51 ISSN: 1600-0455 ISO Abbreviation: Acta Radiol Publication Date: 2010 Apr |
Date Detail:
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Created Date: 2010-03-05 Completed Date: 2010-04-02 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8706123 Medline TA: Acta Radiol Country: England |
Other Details:
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Languages: eng Pagination: 351-9 Citation Subset: IM |
Affiliation:
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Division of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Magnetkamera, G?teborg, Sweden. Goran.Starck@VGregion.se |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Aspartic Acid / analogs & derivatives, metabolism Choline / metabolism Creatine / metabolism Female Hippocampus / metabolism* Humans Imaging, Three-Dimensional Magnetic Resonance Spectroscopy / methods* Male Middle Aged Reference Values Reproducibility of Results Signal Processing, Computer-Assisted Temporal Lobe / metabolism Young Adult |
| Chemical | |
Reg. No./Substance:
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56-84-8/Aspartic Acid; 57-00-1/Creatine; 62-49-7/Choline; 997-55-7/N-acetylaspartate |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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