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Radiologic Findings of Intracranial Hypotension in the Spine and Brain, an Often Missed Diagnosis 2012

General Spine

Ted, T, Chang, BA, MD
Austin, C, Bourgeois, BS, MD, Non ASSR Member
Melissa, L, Neveu, BS, MD, Non ASSR Member
Paul, D, Campbell, BS, MD, Non ASSR Member
Geoffrey, G, Laing, BS,MD, Non ASSR Member

Poster

Purpose

One of the most common symptoms leading imaging by both CT and MRI is headache. The majority of these scans are interpreted as normal; however, intracranial hypotension is an often missed diagnosis which affects a subset of these patients.(1) The symptoms of intracranial hypotension span the range of severe headache to cranial palsy and visual disturbances and in some rare instances severe encephalopathy and death. The purpose of this retrospective study will be to show the classic imaging findings of intracranial hypotension in the spine and brain by CT and MRI in patients with known intracranial hypotension as diagnosed by clinical criteria, imaging findings and measurement of CSF pressure. In addition, treatment techniques will be discussed.

Methods & Materials

A retrospective chart review was performed from the time period of Jan. 1, 2009 - Oct. 1, 2011. Symptomatic patients with low intracranial pressures (<6 cm H2O) as shown by lumbar puncture and with correlating cross sectional imaging within 1 month of the diagnostic lumbar puncture were included. Patients also referred for blood patching who also met the above criteria or those showing improvement in clinical symptoms after blood patching were also included.(2)

Results

Reviewed imaging studies many times showed the classic imaging findings of intracranial hypotension. These included: 1) downward displacement of the brain through the incisura or "slumping of the midbrain" 2) diffuse dural thickening and enhancement 3) venous and dural sinus distension 4) subdural hygromas/hematomas 5) perineural root sleeve cysts 6) epidural contrast collections 7) flaring or other bizarre root sleeve morphology(3,4) While the entire constellation of findings was rarely appreciated in the same patient; patients with intracranial hypotension did display some of the above findings.

Conclusion

Cross sectional imaging for the evaluation of headache continues to grow at an ever increasing rate. The recognition of the classic and less common findings of intracranial hypotension are important as the diagnosis is often not considered, leading to further workup and possibly more, unnecessary, invasive, and ineffective therapies.

References/Financial Disclosures

1) Wouter I. Schievink. Spontaneous Spinal Cerebrospinal Fluid Leaks and Intracranial Hypotension. JAMA. 2006;295(19):2286-2296 (doi:10.1001/jama.295.19.2286) 2) W.I. Schievink,, M.M. Maya, C. Louy, F.G. Moser, and J. Tourje.. Diagnostic Criteria for Spontaneous Spinal CSF Leaks and Intracranial Hypotension. AJNR Am J Neuroradiol May 2008 29: 853-856. 3) Barry M. Rabin, Sudipta Roychowdhury, Joel R. Meyer, Bruce A. Cohen, Kenneth D. LaPat, and Eric J. Russell. Spontaneous Intracranial Hypotension: Spinal MR Findings. AJNR Am J Neuroradiol 19:1034 -1039, June 1998 4) R.I. Farb, R. Forghani, S.K. Lee, D.J. Mikulis, R. Agid. The Venous Distension Sign: A Diagnostic Sign of Intracranial Hypotension at MR Imaging of the Brain. doi: 10.3174/ajnr.A0621AJNR September 2007 28: 1489-149

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