Abstract
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^+SOD1^) in a family with autosomal dominant familial amyotrophic lateral sclerosis (ALS) using diffusion tensor imaging (DTI).
Materials and Methods
A total of eight AFALS^+SOD1^ subjects (aged 17โ43 years) were ageโmatched with 13 healthy controls (aged 19โ45 years) without SOD1 mutations. DTI was carried out on a 1.5T scanner. The diffusion index maps derived were then normalized spatially for voxelโbased analysis. region of interest (ROI)โbased analysis was also carried out.
Results
Our voxelโbased and ROIโbased analysis showed that AFALS^+SOD1^ subjects have decreased fractional anisotropy (FA) (0.5401 vs. 0.5168, P < 0.05) and increased tensor trace (TT) (2.5854 ร 10^โ3^ mm^2^/second vs. 2.6226 ร 10^โ3^ mm^2^/second, P < 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 = 0.5710 ร 10^โ3^ mm^2^/second vs. 0.5943 ร 10^โ3^ mm^2^/second, P < 0.05; left = 0.5666 ร 10^โ3^ mm^2^/second vs. 0.5872 ร 10^โ3^ mm^2^/second, P < 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^+SOD1^ subjects, hitherto unreported. Our results suggest that DTI may detect diffusion abnormalities in AFALS^+SOD1^ subjects before symptoms develop. J. Magn. Reson. Imaging 2007. ยฉ 2007 WileyโLiss, Inc.