Article
Dynamic magnetic resonance imaging of post-traumatic syringomyelia
Dynamische MRT-Untersuchungen zur Verlaufskontrolle bei posttraumatischer Syringomyelie
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Published: | May 30, 2008 |
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Objective: It is generally agreed that the development of syringomyelia (SM) is associated with impaired cerebrospinal fluid (CSF) flow pulsations. There is, however, considerable controversy about the exact pathophysiological mechanism. Since the onset and location of SM are well known in patients with a history of spinal trauma, these patients serve as a model group for studying the development of SM. CSF flow pulsations can be visualised using dynamic MRI. We conducted this study in order to assess whether MRI studies of this model group enable us to gain a better understanding of the pathophysiology of SM.
Methods: Phase-contrast MRI of the entire central nervous system was used to investigate 34 patients with post-traumatic syringomyelia. There were 27 men and 7 women with a mean age of 43 years. In addition, absolute flow velocities and the extension of the SM were measured.
Results: The median time between trauma and diagnosis was 8 years with wide variation (mean time: 11 years, range: 0.5-29 years). Twenty-seven patients had a marked kyphosis at the level of the injury. In this patient group, the frequency of SM increased from the high cervical area to the lower thoracic and lumbar regions, although the majority of injuries were found at the C5 level. In 24 cases, the SM extended from the level of the lesion in both directions. In 5 cases, however, the SM grew only in the caudal direction and in a further 5 cases only in the cranial direction. In the cervical spine, the greatest velocities were measured in the ventral subarachnoid space in 18 of 21 patients. In the thoracic spine, the greatest velocities were found ventrally in 14 cases and dorsally in 10 cases. In the region where the SM was largest in diameter, maximum pulsations were measured ventrally in one third of cases, dorsally in another third, and in the SM itself in the other third. Velocities of more than 7 cm/s were measured in the region where the SM was largest.
Conclusions: The demonstration of CSF flow pulsations is a useful tool for assessing arachnoid scarring. Absolute CSF pulsation velocities, however, do not appear to directly influence the development of SM. This finding contradicts current theories on the pathogenesis of SM.