The Study Of Wallerian Degeneration Using Diffusion Tensor Imaging

Objective To investigate Wallerian degeneration using diffusion tensor magnetic resonance imaging(DTI)Materials and methods 90 participants were enrolled in this study, which was divided into 3 groups. Group 1 consisted of 40 healthy volunteers, 20 males and 20 females(age: 40-69, average: 57), without any neurological symptoms. Group 2 consisted of 10 normal variants, 6 males and 4 females(age: 37-55, average: 45.5). Unsymmetric volume of cerebral peduncle and basilar part of pons was revealed on conventional MRI. Group 3 consisted of 40 patients, 21 males and 19 females(age: 45-73, average: 59.8). The primary foci only located in one side of cerebral hemisphere. The patients not only had neurological deficits but also were found atrophy of cerebral peduncle and basilar part of pons on conventional MRI. All participants were examined by a DTI protocol(TE/TR: minimum/6000ms, matrix: 128x128, NEX: 1, FOV: 24, thickness: 3.0mm, spacing: 0, b value: 0s/mm~2 and 1000s/mm~2, 25 non-collinear directions, scanning time: 2.8min) using a GE Signa Excite II 3.0T MR scanner. The data were postprocessed to generate FA and ADC map on the host computer by a DTI specific software. ROIs were selected on the corticospinal tracts going through cerebral peduncle and basilar part of pons. Bilateral FA and ADC were measured and compared.Results 1. In group 1, the mean FA and FA ratio of the corticospinal tracts incerebral peduncle were 0.73 and 97.6%, and in basilar part of pons were 0.63 and 96.8%. The mean FA of the corticospinal tracts in bilateral cerebral peduncles were 0.74(Ieft) andO.72(right), and in the bilateral basilar part of pons were 0.62(left) and 0.63(right). There was no significant difference in FA of corticospinal tracts between left and right side. ADC of corticospinal tracts in both sides of cerebral peduncle and basilar part of pons had also no significant difference. 2. In group 2, the mean FA and FA ratio of the corticospinal tracts in cerebral peduncle were 0.75(left), 0.74(right) and 97%, and in basilar part of pons were 0.64(left), 0.64(right) and 97.7%. There was no significant difference in FA of corticospinal tracts between group 1 and group2. ADC of corticospinal tracts in both sides of cerebral peduncle and basilar part of pons had also no significant difference. 3. All patients' FA were significantly reduced in the affected side compared to the unaffected side. 39 patients showed atrophy of cerebral peduncle; 21 showed atrophy of basilar part of pons. No patients showed atrophy on both sides of cerebral peduncle and basilar part of pons. FA ratio of patients had significant difference compared to group 1. There was a negative correlation between FA and ADC. ADC of 30 patients were obviously variable, while that of the other 10 were relatively stable.Conclusion DTI can be used to detect and quantify Wallerian degeneration. It can provide useful information for clinicians.