Min-Ji Kim1, Geon-Ho Jahng, Soo-Yeol Lee, Chang-Woo Ryu. 1. Department of Biomedical Engineering, Graduate College of Electronics and Information, Kyung Hee University, Youngin, Gyeonggi-do, South Korea.
Abstract
PURPOSE: The purpose of the authors study was to investigate a functional MRI (fMRI) technique with an ultrashort echo-time (UTE) sequence. METHODS: An UTE-based fMRI technique was applied to 17 young healthy volunteers during visual stimulations on a 3T MRI system. In addition, a blood oxygen level-dependent (BOLD) fMRI image was also obtained to compare functional changes in the brain. The one-sample t-test was performed to investigate increased or decreased signals during baseline and stimulation conditions for all subjects. Furthermore, regions-of-interest were placed by selecting one of the peak activated voxels from the UTE-based and BOLD data to investigate the level of signal changes on the time-course. RESULTS: During the visual activation period, the decreased signals were shown in the visual cortex for the UTE-based method, while both increased and decreased signals were found in the cortex for the BOLD method. The averaged signal changes for the UTE-based data were -0.48 ± 0.37% in the left lingual gyrus, while the changes on the BOLD data were 1.71 ± 0.87% in the right lingual gyrus. CONCLUSIONS: The UTE-based fMRI technique can detect the neuronal activity corresponding to neuronal function. The UTE-based method should be able to improve spatial localization and has much lower sensitivity to field inhomogeneities. Therefore, UTE-based fMRI can be useful to the neurosciences and clinical populations.
PURPOSE: The purpose of the authors study was to investigate a functional MRI (fMRI) technique with an ultrashort echo-time (UTE) sequence. METHODS: An UTE-based fMRI technique was applied to 17 young healthy volunteers during visual stimulations on a 3T MRI system. In addition, a blood oxygen level-dependent (BOLD) fMRI image was also obtained to compare functional changes in the brain. The one-sample t-test was performed to investigate increased or decreased signals during baseline and stimulation conditions for all subjects. Furthermore, regions-of-interest were placed by selecting one of the peak activated voxels from the UTE-based and BOLD data to investigate the level of signal changes on the time-course. RESULTS: During the visual activation period, the decreased signals were shown in the visual cortex for the UTE-based method, while both increased and decreased signals were found in the cortex for the BOLD method. The averaged signal changes for the UTE-based data were -0.48 ± 0.37% in the left lingual gyrus, while the changes on the BOLD data were 1.71 ± 0.87% in the right lingual gyrus. CONCLUSIONS: The UTE-based fMRI technique can detect the neuronal activity corresponding to neuronal function. The UTE-based method should be able to improve spatial localization and has much lower sensitivity to field inhomogeneities. Therefore, UTE-based fMRI can be useful to the neurosciences and clinical populations.