title: Measurements of intracranial pressure and compliance index using 1.5-T clinical MRI machine.
abstract: OBJECTIVE
  To assess a newly proposed noninvasive technique for evaluating intracranial pressure (ICP) index and brain compliance (BC) index based on an inverse analysis of a brain-circulation-equivalent electrical circuit (EC) model, in which cerebrospinal fluid (CSF) flow and arterial flow rates measured by using the phase contrast method are used as currents.
  
  
  METHODS
  Quantitative phase contrast flow measurements were performed by using a 1.5-T scanner for 25 volunteers and 23 patients with chronic increased ICP state. Bilateral carotid and verrtebral arteries and CSF flows were modeled by a pair of electrical circuits inductively coupled by a transformer. The ICP index was defined as the voltage of the second order circuit, while the BC index was calculated as the ratio between the mutual indeuctance of the transformer and the reactance in the second order circuit.
  
  
  RESULTS
  The ICP index obtained by the EC correlated well with the pressure gradient obtained by the Navier-Stokes Technique (NS-PG). The combination of NS-PG and BC index by the EC appeared to be appropriate for characterizing the brain circulation status of the volunteers.
  
  
  CONCLUSIONS
  This noninvasive ICP and BC index measurement technique is more useful for asessment of intracranial condition.
authors.forename: Hideki
authors.initials: H
authors.lastname: Atsumi
authors.affiliation: Department of Neurosurgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. mike@is.icc.u-tokai.ac.jp.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Matsumae
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hirayama
authors.forename: Kagayaki
authors.initials: K
authors.lastname: Kuroda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001921:Brain / Q000503:physiopathology*; D002552:Cerebral Ventricles; D002555:Cerebrospinal Fluid / Q000502:physiology; D002560:Cerebrovascular Circulation; D002648:Child; D003187:Compliance; D005260:Female; D006801:Humans; D007427:Intracranial Pressure; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D064926:Neurophysiological Monitoring / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult