Abstract
The results of this study suggest that abnormal cerebrospinal fluid flow patterns and peak velocities in the foramen magnum may be characteristic of idiopathic syringomyelia in some patients.
Purpose
To measure cerebrospinal fluid (CSF) flow velocities in the foramen magnum in patients with idiopathic syringomyelia (IS).
Materials and Methods
Patient consent for this retrospective study was waived by the institutional review board within the guidelines of HIPAA. The authors reviewed the medical records of a neurosurgery specialty clinic to identify patients with IS—that is, syringomyelia without evidence of Chiari malformation, tumor, or substantial spine trauma. Patients without syringomyelia or Chiari malformation identified from the review served as control subjects. The data of patients and control subjects who had undergone phase-contrast magnetic resonance (MR) imaging were included in the study. MR flow images were inspected for evidence of synchronous bidirectional CSF flow and heterogeneous spatial and temporal flow patterns. Peak CSF flow velocities in the IS and control groups were calculated, and differences were tested for statistical significance by using the Wilcoxon rank sum test.
Results
Eight patients who met the criteria for IS and six who met the criteria to serve as control subjects were identified. The phase-contrast MR images obtained in five of the eight patients with IS and in none of the control subjects depicted synchronous bidirectional flow and/or large flow jets. Mean peak systolic (caudal) CSF flow velocities were 6.7 cm/sec in the IS group and 3.6 cm/sec in the control group; the difference was significant (P < .01). Mean peak diastolic (cephalic) velocities were 3.9 and 3.4 cm/sec in the IS and control groups, respectively; the difference was not significant (P = .36).
Conclusion
Some patients with IS have increased peak systolic CSF flow velocities.
© RSNA, 2009
References
- 1. . Elucidating the pathophysiology of syringomyelia. J Neurosurg 1999;91:553–562.
- 2. . Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils: implications for diagnosis and treatment. J Neurosurg 1994;80:3–15.
- 3. . Significance of cerebellar tonsillar position on MR. AJNR Am J Neuroradiol 1986;7:795–799.
- 4. . Pathogenesis and mechanics of spinal cord cysts: a new hypothesis based on magnetic resonance studies of cerebrospinal fluid dynamics. Int J Neuroradiol 1999;5:61–78.
- 5. . Cerebrospinal fluid flow in foramen magnum: temporal and spatial patterns at MR imaging in volunteers and in patients with Chiari I malformation. Radiology 2004;232:229–236.
- 6. . Characterization of CSF hydrodynamics in the presence and absence of tonsillar ectopia by means of computational flow analysis (CFA). AJNR Am J Neuroradiol 2009;30:941–946.
- 7. . Foramen magnum cerebrospinal fluid flow characteristics in children with Chiari I malformation before and after craniocervical decompression. J Neurosurg 2004;101(2 suppl):169–178.
- 8. . The resolution of syringohydromyelia without hindbrain herniation after posterior fossa decompression. J Neurosurg 1998;89:212–216.
- 9. . Analysis of the posterior fossa in children with the Chiari 0 malformation. Neurosurgery 2001;48:1050–1055.
- 10. . Clinical and neuroimaging features of “idiopathic” syringomyelia. Neurology 2004;62:791–794.
- 11. . Cardiac-gated phase contrast magnetic resonance imaging of cerebrospinal fluid flow in the diagnosis of idiopathic syringomyelia. Neurosurgery 2008;63:1139–1144.
- 12. . Unraveling the riddle of syringomyelia. Neurosurg Rev 2006;29:251–263.
- 13. . Accuracy of CSF flow studies in the differentiation of symptomatic Chiari I malformation from asymptomatic incidental tonsillar ectopia. Radiology 2007;245:532–540.
Article History
Received December 1, 2008; revision requested February 13, 2009; revision received March 2; accepted April 1; final version accepted April 27.Published in print: Oct 2009
