MRI Diagnosis of Wallerian Degeneration of Pyramidal Tract

Objective To explore the application of MRI diagnosis of Wallerian degeneration of pyramidal tract after brain injury.Methods Twenty-two patients with Wallerian degeneration of pyramidal tract after brain injury underwent MRI examination(FSE T1WI TR/TE 2 286/19.6 ms;T2WI TR/TE 4 300/113 ms;T2 Flair sequence TR/TE 8 502/133 ms;FOV 24 cm;Matrix 320×256;NEX 1-2;slice thickness:6 mm;interlayer spacing 1 mm;layers 21).An axial DWI scan(b value 1 000 s·mm-2) was performed in all patients.Among them,3D-TOF-MRA examination(TR/TE 26/6.8 ms) was additionally carried out in 10 patients.Results Among the 22 patients,12 underwent MRI examination at ≥4 weeks-≤12 months after brain injury and showed elongated T1 and T2 signals in pyramidal tract ipsilateral to the lesion and slight atrophy of ipsilateral cerebral peduncle and pons.Two patients underwent MRI examination at 4 weeks after brain injury and showed longer T1 and long T2 signals.Eight patients underwent MRI examination at 1 year and showed primary lesion,cerebral peduncle and pons atrophy,and increased T2 Flair signal as scattered patches.Conclusion MRI may clearly show Wallerian degeneration of pyramidal tract after brain injury and can help clinicians treat impaired motor function.