Preliminary study of cervical spinal cord in patients with amyotrophic lateral sclerosis using MR diffusion tensor imaging

Abstract

Objective To determine whether normal-appearing cervical spinal cord in patients with amyotrophic lateral sclerosis (ALS) has abnormal changes based on the quantitative measurement in healthy volunteers. Methods Conventional MRI and axial DTI were obtained in 16 patients with ALS (ALS group) and 16 age-matched control subjects (normal group) . ADC, fractional anisotropy (FA) and relative anisotropy(RA)imagcs were obtained on workstation (AW4. 2). ROIs (5 mm × 5 mm) were placed in anterior funicalus, posterior funiculus, and bilateral lateral corticospinal tracts (LCTs), respectively, at the same slice (C3). Independent-sample t test was used for comparison of parameters between the two groups. Correlations between DTI parameters of ALS and ALS course, Norris score, and ALSFRS were carried out separately by Pearson correlation analysis. Results FA and RA values of bilateral LCTs were decreased significantly. FA/RA values of left LCT were 0.762±0.089 and 0.762±0.107 in ALS group, while they were 0.863±0.098 and 0.890±0.105 in control group, respectively. FA/RA values of right LCT were 0.751±0.065 and 0.772±0.082 in ALS group, and they were 0.843±0.118 and 0.863±0.134 in control group, respectively, they were decreased significantly (t = 2.575、4.195、2.246、2.218, P 0.05) between ADC values of left and right CSTs in ALS group [(0.744±0.162) × 10-3, (0.767±0.141) × 10-3 mm2/s] and control group [(0.640±0.149) ×10-3, (0.643±0.168) ×10-3 mm2/s)]. FA, RA and ADC values of ALS patients in anterior funiculus were 0.637±0.113, 0.622±0.138, (0.950±0.354)×10-3 mm2/s, in control group they were 0.670±0.117, 0.656±0.136, (0.865±0.238) × 10-3 mm2/s, there were no significant differences (t = 0.854, - 0.704, - 1.155,P > 0.05). FA, RA and ADC values of ALS patients in posterior funieulus were 0.886±0.073, 0.920±0.100, (0.613±0.137)×10-3 mm2/s, in control group they were 0.906±0.078, 0.914±0.135, (0.636±0.224) × 10-3 mm2/s, there were no significant differences (t = 1.655, - 0.148, - 1.360; P > 0.05). No significant correlation existed between FA and RA values and disease course, Norris and ALSFRS score (P > 0.05), in left and right LCTs. Conclusion DTI with SE-EPI technique is simple and sensitive to detect the pathological changes of the cervical spinal cord in ALS patients. DTI can reveal the abnormalities which are normal appearing on conventional T2WI. Key words: Amyotrophic lateral sclerosis; Diffusion magnetic resonance imaging; Spinal cord