Purpose:To determine whether diffusion abnormalities can be observed in nonsymptomatic family members with a known causative Cu/Zn superoxide dismutase mutation (asymptomatic familial amyotrophic lateral sclerosis; AFALS ϩSOD1 ) in a family with autosomal dominant familial amyotrophic lateral sclerosis (ALS) using diffusion tensor imaging (DTI). Materials and Methods:A total of eight AFALS ϩSOD1 subjects (aged 17-43 years) were age-matched with 13 healthy controls (aged 19 -45 years) without SOD1 mutations. DTI was carried out on a 1.5T scanner. The diffusion index maps derived were then normalized spatially for voxelbased analysis. region of interest (ROI)-based analysis was also carried out.Results: Our voxel-based and ROI-based analysis showed that AFALS ϩSOD1 subjects have decreased fractional anisotropy (FA) (0.5401 vs. 0.5168, P Ͻ 0.05) and increased tensor trace (TT) (2.5854 ϫ 10 -3 mm 2 /second vs. 2.6226 ϫ 10 -3 mm 2 /second, P Ͻ 0.04) at the posterior limb of the internal capsule compared to the control subjects. Increased radial diffusivity (E (2,3)/2 ) was detected on both sides (right ϭ 0.5710 ϫ 10 -3 mm 2 /second vs. 0.5943 ϫ 10 -3 mm 2 /second, P Ͻ 0.05; left ϭ 0.5666 ϫ 10 -3 mm 2 / second vs. 0.5872 ϫ 10 -3 mm 2 /second, P Ͻ 0.05). No significant change in axial diffusivity (E 1 ) was detected. Conclusion:Abnormal diffusivity was found at the posterior limb of the internal capsule in AFALS ϩSOD1 subjects, hitherto unreported. Our results suggest that DTI may detect diffusion abnormalities in AFALS ϩSOD1 subjects before symptoms develop.

Purpose To demonstrate the presence of MT asymmetry in human cervical spinal cord due to the interaction between bulk water and semisolid macromolecules (conventional MT), and the chemical exchange dependent saturation transfer (CEST) effect. Materials and methods MT asymmetry in the cervical spinal cord (C3/C4 - C5) was investigated in 14 healthy male subjects with a 3T magnetic resonance (MR) system. Both spin-echo (SE) and gradient-echo (GE) echo-planar imaging (EPI) sequences, with low power off-resonance radiofrequency irradiation at different frequency offsets, were used. Results Our results show that the z-spectrum in gray/white matter is asymmetrical about the water resonance frequency in both SE-EPI and GE-EPI, with a more significant saturation effect at the lower frequencies (negative frequency offset) far away from water and at the higher frequencies (positive offset) close to water. These are attributed mainly to the conventional MT and CEST effects respectively. Furthermore, the amplitude of MT asymmetry is larger in SE-EPI sequence than in GE-EPI sequence in the frequency range of amide protons. Conclusion Our results demonstrate the presence of MT asymmetry in human cervical spinal cord, which is consistent with the ones reported in the brain.

The protocolJor spinal DTI and tractographv with high SNR and spatial resolution has been developed and tested on 6 hea1th.v suhjects and I CSMpatient in a 3T system. Fiber bundles were traced and were found running parallel to the cervical spinal cord correlating with the neuronal anat0m.v in normal subjects. The FA maps showed consistent low FA region connecting all spinal levels, which corresponded to the grey ntatler structure in anatomical imaging. Spinal DTI in CSM showed dIfi~.~ivity increa.~e at compression sites. The proposed diffusion eigenvector-based method was able todtfferentiate hehveen h and k even when there was a dra.stic diffusivity change at compressed regions in CXM, which mav facilitate better understanding of the pathoph.vsiologv of CSM. Our results indicated that using the current imaging and post-processing protocols, spinal DTI can he achieved with better gre.y/n,hite matter contrast, high inter-subject reproducibili~ and diagnostic abiliQ.