title: Determination of cranio-spinal canal compliance distribution by MRI: Methodology and early application in idiopathic intracranial hypertension.
abstract: OBJECTIVE
  To develop a method for derivation of the cranial-spinal compliance distribution, assess its reliability, and apply to obese female patients with a diagnosis of idiopathic intracranial hypertension (IIH).
  
  
  METHODS
  Phase contrast-based measurements of blood and cerebrospinal fluid (CSF) flows to, from, and between the cranial and spinal canal compartments were used with lumped-parameter modeling to estimate systolic volume and pressure changes from which cranial and spinal compliance indices are obtained. The proposed MRI indices are analogous to pressure volume indices (PVI) currently being measured invasively with infusion-based techniques. The consistency of the proposed method was assessed using MRI data from seven aged healthy subjects. Measurement reproducibility was assessed using five repeated MR scans from one subject. The method was then applied to compare spinal canal compliance contribution in seven IIH patients and six matched healthy controls.
  
  
  RESULTS
  In the healthy subjects, as expected, spinal canal contribution was consistently larger than the cranial contribution (average value of 69%). Measurement variability was 8%. In IIH, the spinal canal contribution is significantly smaller than normal controls (60 versus 78%, P < 0.03).
  
  
  CONCLUSIONS
  An MRI-based method for derivation of compliance indices analogous to PVI has been implemented and applied to healthy subjects. The application of the method to obese IIH patients suggests a spinal canal involvement in the pathophysiology of IIH.
authors.affiliation: Department of Radiology, University of Miami, Miami, Florida, USA.
authors.forename: Rong-Wen
authors.initials: RW
authors.lastname: Tain
authors.forename: Ahmet M
authors.initials: AM
authors.lastname: Bagci
authors.forename: Byron L
authors.initials: BL
authors.lastname: Lam
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Sklar
authors.forename: Birgit
authors.initials: B
authors.lastname: Ertl-Wagner
authors.forename: Noam
authors.initials: N
authors.lastname: Alperin
mesh_terms: D000328:Adult; D000368:Aged; D002555:Cerebrospinal Fluid / Q000502:physiology; D003187:Compliance; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011559:Pseudotumor Cerebri / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D012886:Skull / Q000502:physiology*; D013115:Spinal Canal / Q000502:physiology*