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ABSTRACT: The aim of this study is to assess plastic changes of the sensorimotor cortex (SMC) in patients with traumatic brachial plexus injury (BPI) using functional magnetic resonance imaging (fMRI). Twenty patients with traumatic BPI underwent fMRI using blood oxygen level-dependent technique with echo-planar imaging before the operation. Sixteen patients underwent their second fMRI at approximately one year after injury. The subjects performed two tasks: a flexion-extension task of the affected elbow and a task of the unaffected elbow. After activation, maps were generated, the number of significantly activated voxels in SMC contralateral to the elbow movement in the affected elbow task study (N(af)) and that in the unaffected task study (N(unaf)) were counted. An asymmetry index (AI) was calculated, where AI = (N(af) - N(unaf))/(N(af) + N(unaf)). Ten healthy volunteers were also included in this fMRI study. The AI of the first fMRI of the patients with BPI was significantly lower than that of the healthy subjects (P = 0.035). The AI of the second fMRI significantly decreased compared with that of the first fMRI (P = 0.045). Brain reorganization associates with peripheral nervous changes after BPI and after operation for functional reconstruction.
TheScientificWorldJOURNAL 01/2012; 2012:501751. · 1.66 Impact Factor
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Masami Goto,
Yuuichi Suzuki,
Osamu Abe,
Naoto Hayashi,
Shigeki Aoki,
Harushi Mori,
Tomohiko Masumoto,
Yasushi Watanabe, Yoshirou Satake,
Kenji Ino,
Keiichi Yano,
Kyouhito Iida,
Kazuo Mima,
Kuni Ohtomo
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ABSTRACT: A voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) was used for quantitative analysis of parahippocampal atropy with 1.5-tesla (T) MRI in a voxel-wise manner. The analysis of images acquired under a different imaging condition provides an error factor that has a calculated value. Clinical application of 3T-MRI is necessary for establishing a normal data base (N-DB) specific for 3T-MRI data, which permits appropriate application of VSRAD. We established an N-DB specific for 3T-MRI for use in VSRAD. The "Z-score of the parahippocampal gyrus" was 0.79 +/- 0.32, and the N-DB of each age group did not have a big deflection when we analyzed a group of physically unimpaired persons in an N-DB specific for 3T-MRI. Therefore, we were able to confirm the validity of the customized N-DB. The "Z-score of the parahippocampal gyrus" was 1.62 +/- 0.47 for the N-DB of VSRAD. The numerical value was high for the group of physically unimpaired persons.
Radiological Physics and Technology 07/2008; 1(2):196-200.
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Masami Goto,
Shigeki Aoki,
Naoto Hayashi,
Harushi Mori,
Yasushi Watanabe,
Kenji Ino, Yoshirou Satake,
Katuji Nishida,
Haruo Sato,
Kyouhito Iida,
Kazuo Mima,
Kuni Ohtomo
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ABSTRACT: As the PROPELLER sequence is a combination of the radial scan and fast-spin-echo (FSE) sequence, it can be considered an FSE sequence with a motion correlation. However, there are some differences between PROPELLER and FSE owing to differences in k-space trajectory. We clarified the imaging characteristics of PROPELLER T2-weighted imaging (T2WI) for different parameters in comparison with usual FSE T2WI. When the same parameters were used, PROPELLER T2WI showed a higher signal-to-noise ratio (SNR) and lower spatial resolution than usual FSE. Effective echo time (TE) changed with different echo train lengths (ETL) or different bandwidths on PROPELLER, and imaging contrast changed accordingly to be more effective.
Nippon Hoshasen Gijutsu Gakkai zasshi 12/2004; 60(11):1585-91.
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Masami Goto,
Shigeki Aoki,
Naoto Hayashi,
Harushi Mori,
Yasushi Watanabe,
Kenji Ino, Yoshirou Satake,
Katuji Nishida,
Haruo Sato,
Kyouhito Iida,
Kazuo Mima,
Kuni Ohtomo
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ABSTRACT: To evaluate the ability of periodically rotated overlapping parallel lines with enhanced reconstruction diffusion-weighted imaging (PROPELLER DWI) to distinguish between vessel occlusion and slow flow.
Using a flow phantom with various velocities (1.37 to 11.1 cm/s), the signal-intensity ratios of the phantom, with the intensity of no flow as baseline, were measured using the following imaging sequences: PROPELLER DWI, spin-echo T1-weighted imaging (SE T1WI), fast-spin-echo T2-weighted imaging (FSE T2WI), two-dimensional phase-contrast imaging (2D PC), and two-dimensional time-of-flight imaging (2D TOF). The b-factor of PROPELLER DWI was varied from 0 to 1000 s/mm(2). The velocity encoding of 2D PC was varied from 2 to 30 cm/s.
At the lowest flow velocity (1.37 cm/s) , the signal-intensity ratio was 0.0075 for PROPELLER DWI (b-factor=1000 s/mm(2)), 1.8 for SE T1WI, 0.67 for FSE T2WI, 11 for 2D PC (velocity encoding=2 cm/s), and 1.4 for 2D TOF. The signal-intensity ratio was smallest for PROPELLER DWI, even when the reciprocals of the signal-intensity ratio of 2D PC or 2D TOF were considered.
The results indicate that PROPELLER DWI provides the best signal intensity-ratio between vessel occlusion and slow flow. Although DWI with single-shot echo-planar imaging (EPI) or multi-shot EPI may have similarly high sensitivity for slow flow, these sequences do not have high spatial resolution or robustness to susceptibility artifacts. PROPELLER DWI would be a better choice for distinguishing between occluded and low-velocity arteries in the skull base or parasellar regions.
Nippon Hoshasen Gijutsu Gakkai zasshi 12/2004; 60(11):1519-25.
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Harushi Mori,
Shigeki Aoki,
Osamu Abe,
Yoshitaka Masutani,
Tomohiko Masumoto,
Naoto Hayashi,
Takeharu Yoshikawa,
Yasushi Watanabe, Yoshirou Satake,
Kuni Ohtomo,
Hiroyuki Kabasawa
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ABSTRACT: Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) MR imaging (MRI) has a unique ability to correct motion artifacts and is expected to be useful in diffusion-weighted MRI. This article describes preliminary experiences with PROPELLER MRI. PROPELLER uses a radial scan variation of the fast spin-echo sequence and it shows much less spatial deterioration than the echo-planar imaging sequence. To determine the optimal parameters of this technique, we calculated the signal intensities of phantoms and brains in various settings. PROPELLER MR examinations were also performed in 66 patients for clinical use. PROPELLER MRI appears to be a promising and useful technique.
Nihon Igaku Hoshasen Gakkai zasshi. Nippon acta radiologica 06/2002; 62(6):287-9.
