TY - JOUR
T1 - Noninvasive intracranial compliance from MRI-based measurements of transcranial blood and CSF flows
T2 - Indirect versus direct approach
AU - Tain, Rong Wen
AU - Alperin, Noam
N1 - Funding Information:
Manuscript received April 23, 2008; revised July 8, 2008. First published October 13, 2008; current version published April 15, 2009. This work was supported by the National Institutes of Health (NIH) under Award R01NS052122. Asterisk indicates corresponding author.
PY - 2009/3
Y1 - 2009/3
N2 - Intracranial compliance (ICC) determines the ability of the intracranial compartment to accommodate an increase in volume without a large increase in intracranial pressure (ICP). The clinical utilization of ICC is limited by the invasiveness of current measurement. Several investigators attempted to estimate ICC noninvasively, from magnetic resonance imaging (MRI) measurements of cerebral blood and cerebral spinal fluid flows, either using indirect measures of ICC or directly by measuring the ratio of the changes in intracranial volume and pressure during the cardiac cycle. The indirect measures include the phase lag between the cerebrospinal fluid (CSF) and its driving force, either arterial inflow or net transcranial blood flow. This study compares the sensitivity of phase-based and amplitude-based measures of ICC to changes in ICC. In vivo volumetric blood and CSF flows measured by MRI phase contrast from healthy volunteers and from patients with elevated ICP were used for the comparison. An RLC circuit model of the craniospinal system was utilized to simulate the effect of a change in ICC on the CSF flow waveform. The simulations demonstrated that amplitude-based measures of ICC are considerably more sensitive than phase-based measures, and among the amplitude-based measures, the ICC index provides the most reliable estimate of ICC.
AB - Intracranial compliance (ICC) determines the ability of the intracranial compartment to accommodate an increase in volume without a large increase in intracranial pressure (ICP). The clinical utilization of ICC is limited by the invasiveness of current measurement. Several investigators attempted to estimate ICC noninvasively, from magnetic resonance imaging (MRI) measurements of cerebral blood and cerebral spinal fluid flows, either using indirect measures of ICC or directly by measuring the ratio of the changes in intracranial volume and pressure during the cardiac cycle. The indirect measures include the phase lag between the cerebrospinal fluid (CSF) and its driving force, either arterial inflow or net transcranial blood flow. This study compares the sensitivity of phase-based and amplitude-based measures of ICC to changes in ICC. In vivo volumetric blood and CSF flows measured by MRI phase contrast from healthy volunteers and from patients with elevated ICP were used for the comparison. An RLC circuit model of the craniospinal system was utilized to simulate the effect of a change in ICC on the CSF flow waveform. The simulations demonstrated that amplitude-based measures of ICC are considerably more sensitive than phase-based measures, and among the amplitude-based measures, the ICC index provides the most reliable estimate of ICC.
KW - Cerebrospinal fluid (CSF)
KW - Craniospinal system
KW - Intracranial compliance (ICC)
KW - Lumped-parameter modeling
KW - Phase contrast magnetic resonance imaging (PCMRI)
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U2 - 10.1109/TBME.2008.2006010
DO - 10.1109/TBME.2008.2006010
M3 - Article
C2 - 19389680
AN - SCOPUS:65349103048
VL - 56
SP - 544
EP - 551
JO - IRE transactions on medical electronics
JF - IRE transactions on medical electronics
SN - 0018-9294
IS - 3
M1 - 4637865
ER -