The Significance of Echo Time in fMRI BOLD Contrast: A Clinical Study during Motor and Visual Activation Tasks at 1.5 T
| Autor: | Themistoklis Boursianis, Georgios Kalaitzakis, Katerina Nikiforaki, Emmanouela Kosteletou, Despina Antypa, George A. Gourzoulidis, Apostolos Karantanas, Efrosini Papadaki, Panagiotis Simos, Thomas G. Maris, Kostas Marias |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Tomography, Vol 7, Iss 3, Pp 333-343 (2021) |
| Druh dokumentu: | article |
| ISSN: | 2379-139X 2379-1381 |
| DOI: | 10.3390/tomography7030030 |
| Popis: | Blood Oxygen Level Dependent (BOLD) is a commonly-used MR imaging technique in studying brain function. The BOLD signal can be strongly affected by specific sequence parameters, especially in small field strengths. Previous small-scale studies have investigated the effect of TE on BOLD contrast. This study evaluates the dependence of fMRI results on echo time (TE) during concurrent activation of the visual and motor cortex at 1.5 T in a larger sample of 21 healthy volunteers. The experiment was repeated using two different TE values (50 and 70 ms) in counterbalanced order. Furthermore, T2* measurements of the gray matter were performed. Results indicated that both peak beta value and number of voxels were significantly higher using TE = 70 than TE = 50 ms in primary motor, primary somatosensory and supplementary motor cortices (p < 0.007). In addition, the amplitude of activation in visual cortices and the dorsal premotor area was also higher using TE = 70 ms (p < 0.001). Gray matter T2* of the corresponding areas did not vary significantly. In conclusion, the optimal TE value (among the two studied) for visual and motor activity is 70 ms affecting both the amplitude and extent of regional hemodynamic activation. |
| Databáze: | Directory of Open Access Journals |
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