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Three-dimensional visualization of white matter fibers using diffusion tensor magnetic resonance imaging of the brain
International Congress Series 1256 (2003) 1311
Three-dimensional visualization of white matter fibers using diffusion tensor magnetic resonance imaging of the brain Youichi Yamazaki a, Kenya Murasea,*, Chiaki Oohiraa, Yuko Shakudoa, Ichiro Sogabeb, Hiroshi Higashinob, Keiichi Kikuchib a
Department of Medical Engineering, Osaka University Medical School, 1-7 Yamadaoka 565-0871, Osaka, Japan b Department of Radiology, Ehime Prefectural Imabari Hospital, Ehime, Japan Received 10 March 2003; received in revised form 10 March 2003; accepted 11 March 2003
Keywords: Visualization; White matter fibers; Diffusion tensor
1. Introduction Diffusion tensor imaging (DTI) provides new and unique opportunities for studying the white matter architecture. The purpose of this study was to develop a software that can track white matter fibers using DTI. 2. Methods DTI data were acquired using a 1.5 T MRI system (Magnetom Symphony, Siemens) (TR = 1700 – 1800 ms, TE = 91 – 98 ms, matrix size = 128 128, field of view = 22 22 cm, slice thickness = 3 mm, and acquisition time = 5 min). Diffusion sensitization was performed along six directions using a b-value of 600 s/mm2 to measure full diffusion tensor matrix (DTM). The eigenvalues and eigenvectors were calculated from the DTM. The fractional anisotropy (FA) was also calculated. Fiber tracking was performed as follows. First, a user set up the starting (seed) point in a 3-D space. Second, the direction of fibers in the starting point was calculated from the direction of the eigenvector with the largest eigenvalue. Then, a straight line having the steplength given beforehand was propagated in this direction, and the direction of fibers in a reaching point was also calculated. Fiber tracking was terminated when it reached a voxel with FA lower than 0.2. To investigate the validity of our software, we performed phantom studies using asparagus and human studies. 3. Results In phantom studies, the 3-D tracts of asparagus were successfully displayed. In human studies, the 3-D fiber tracts of corpus callosum and crus posterius were clearly demonstrated. Pyramidal tracts were also clearly observed. 4. Conclusions Our software will be applicable and useful in both research and clinical settings, especially for research of brain development and for surgical operation of brain tumors as a navigation system.
* Corresponding author. Tel./fax: +81-6-6879-2571. E-mail address: [email protected] (K. Murase). 0531-5131/03 D 2003 Published by Elsevier Science B.V. doi:10.1016/S0531-5131(03)00223-1
Three-dimensional visualization of white matter fibers using diffusion tensor magnetic resonance imaging of the brain Youichi Yamazaki a, Kenya Murasea,*, Chiaki Oohiraa, Yuko Shakudoa, Ichiro Sogabeb, Hiroshi Higashinob, Keiichi Kikuchib a
Department of Medical Engineering, Osaka University Medical School, 1-7 Yamadaoka 565-0871, Osaka, Japan b Department of Radiology, Ehime Prefectural Imabari Hospital, Ehime, Japan Received 10 March 2003; received in revised form 10 March 2003; accepted 11 March 2003
Keywords: Visualization; White matter fibers; Diffusion tensor
1. Introduction Diffusion tensor imaging (DTI) provides new and unique opportunities for studying the white matter architecture. The purpose of this study was to develop a software that can track white matter fibers using DTI. 2. Methods DTI data were acquired using a 1.5 T MRI system (Magnetom Symphony, Siemens) (TR = 1700 – 1800 ms, TE = 91 – 98 ms, matrix size = 128 128, field of view = 22 22 cm, slice thickness = 3 mm, and acquisition time = 5 min). Diffusion sensitization was performed along six directions using a b-value of 600 s/mm2 to measure full diffusion tensor matrix (DTM). The eigenvalues and eigenvectors were calculated from the DTM. The fractional anisotropy (FA) was also calculated. Fiber tracking was performed as follows. First, a user set up the starting (seed) point in a 3-D space. Second, the direction of fibers in the starting point was calculated from the direction of the eigenvector with the largest eigenvalue. Then, a straight line having the steplength given beforehand was propagated in this direction, and the direction of fibers in a reaching point was also calculated. Fiber tracking was terminated when it reached a voxel with FA lower than 0.2. To investigate the validity of our software, we performed phantom studies using asparagus and human studies. 3. Results In phantom studies, the 3-D tracts of asparagus were successfully displayed. In human studies, the 3-D fiber tracts of corpus callosum and crus posterius were clearly demonstrated. Pyramidal tracts were also clearly observed. 4. Conclusions Our software will be applicable and useful in both research and clinical settings, especially for research of brain development and for surgical operation of brain tumors as a navigation system.
* Corresponding author. Tel./fax: +81-6-6879-2571. E-mail address: [email protected] (K. Murase). 0531-5131/03 D 2003 Published by Elsevier Science B.V. doi:10.1016/S0531-5131(03)00223-1