MRI findings in a case of spinal cord Wallerian degeneration following trauma

W degeneration is a well-known entity which represents distal axonal degeneration and myelin disintegration following interruption of any axon from its cellular connection. It was first described by Weller in 1850 and is named after him.1 It is well described entity on imaging in brain but is less well described in spinal cord with only few reports in radiological literature and in post mortem pathological studies.1-4 We described sequential magnetic resonance imaging (MRI) findings in a case of spinal cord injury with development of changes of Wallerian degeneration in delayed scan. A 35-year-old male patient presented for MRI. He had history of fall 6 months back that was followed by quadriparesis with reduced power in bilateral upper and lower limbs (3/5). Magnetic resonance imaging at that time showed cord contusion with hyperintense signal in spinal cord at C3 to C4-5 levels with associated degenerative disc disease. No fracture or dislocation was seen (Figure 1). Patient was managed conservatively. He now presented with paresthesias in bilateral lower limbs and reduced grip power in bilateral upper limbs that was worsened for last one month. Magnetic resonance imaging showed small focal syrinx in the cord at C4-5 level. Abnormal signal was seen in the dorsal column of spinal cord extending superiorly with extension upto cervico-medullary junction. Hyperintense signal was also seen in bilateral lateral corticospinal tracts inferior to the level of syrinx extending up to C7 vertebral level. Based on the characteristic findings, a diagnosis of post traumatic Wallerian degeneration of spinal cord was made. Four stages of Wallerian degeneration in brain were described by Kuhn in brain in 1989.1,4 In the first stage in first four weeks, there is degeneration of axons without any significant change in the myelin sheath and normal signal intensity on MR imaging. Stage II lasts for 4-14 weeks and is characterized by myelin protein breakdown process with relative preservation of myelin lipids and is characterized by T2W hypointense signal on MRI. Stage III occurs after 14 weeks and is characterized by lipid breakdown in myelin with gliosis and increased water content and shows hyperintense signal on T2W images. Stage IV occurs years after the injury and is characterized by atrophic changes with persistence of hyperintense signal. These stages described for brain changes are expected to be similar in spinal cord Wallerian degeneration. These stages were described prior to 1990 when conventional spin echo (CSE) was used for imaging acquisition of T2W images. After 1990, fast spin echo (FSE) technique became the mainstay for acquisition of T2W images and therefore the above signal intensities may not be completely reproducible. There is a fundamental difference in Wallerian degeneration in central nerve system (CNS) when Clinical Note