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Assessment of craniospinal pressure-volume indices
Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
Department of Radiology, University of Miami, Miami, Florida.
Visa övriga samt affilieringar
2010 (Engelska)Ingår i: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 31, nr 9, s. 1645-1650Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

BACKGROUND AND PURPOSE: The PVI(CC) of the craniospinal compartment defines the shape of the pressure-volume curve and determines the damping of cyclic arterial pulsations. Despite no reports of direct measurements of the PVI(CC) among healthy elderly, it is believed that a change away from adequate accommodation of cardiac-related pulsations may be a pathophysiologic mechanism seen in neurodegenerative disorders such as Alzheimer disease and idiopathic normal pressure hydrocephalus. In this study, blood and CSF flow measurements are combined with lumbar CSF infusion measurements to assess the craniospinal PVI(CC) and its distribution of cranial and spinal compartments in healthy elderly.

MATERIALS AND METHODS: Thirty-seven healthy elderly were included (60-82 years of age). The cyclic arterial volume change and the resulting shift of CSF to the spinal compartment were quantified by PC-MR imaging. In addition, each subject underwent a lumbar CSF infusion test in which the magnitude of cardiac-related pulsations in intracranial pressure was quantified. Finally, the PVI was calculated by using a mathematic model.

RESULTS: After excluding 2 extreme values, the craniospinal PVI(CC) was calculated to a mean of 9.8 ± 2.7 mL and the estimated average 95% confidence interval of individual measurements was ± 9%. The average intracranial and spinal contributions to the overall compliance were 65% and 35% respectively (n = 35).

CONCLUSIONS: Combining lumbar CSF infusion and PC-MR imaging proved feasible and robust for assessment of the craniospinal PVI(CC). This study produced normative values and showed that the major compensatory contribution was located intracranially.

Ort, förlag, år, upplaga, sidor
2010. Vol. 31, nr 9, s. 1645-1650
Identifikatorer
URN: urn:nbn:se:umu:diva-36883DOI: 10.3174/ajnr.A2166ISI: 000283011300019PubMedID: 20595369OAI: oai:DiVA.org:umu-36883DiVA, id: diva2:356570
Tillgänglig från: 2010-10-13 Skapad: 2010-10-13 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Ingår i avhandling
1. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects
Öppna denna publikation i ny flik eller fönster >>Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects
2012 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.

Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation.

A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies.

The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found.

Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile stress were assessed in healthy elderly. The biomarkers were extracted from invasive CSF pressure measurements as well as 2D PCMRI acquisitions. The volumes of temporal cortex, frontal cortex and hippocampus were negatively related to the magnitude of cardiac-related intracranial pulsatility.

Finally, a potentially improved workflow to assess the volume of arterial pulsatility using time resolved, four-dimensional phase contrast MRI measurements (4D PCMRI) was evaluated. The measurements showed good agreement with 2D PCMRI acquisitions.

In conclusion, this work showed that 2D PCMRI is a feasible tool to study the pulsatile waveforms of cerebral blood and CSF flow. Conventional views regarding the magnitude and distribution of craniospinal compliance was challenged, with important implications regarding the understanding of how intracranial vascular pulsatility is absorbed. A first counterpoint to previous near-uniform observations of obstructions in the internal jugular veins in multiple sclerosis was provided. It was demonstrated that large cardiac- related intracranial pulsatility were related to smaller volumes of brain regions that are important in neurodegenerative diseases among elderly. This represents a strong rationale to further investigate the role of excessive intracranial pulsatility in cognitive impairment and dementia. For that work, 4D PCMRI will facilitate an effective analysis of cerebral blood flow and pulsatility. 

Ort, förlag, år, upplaga, sidor
Umeå: Umeå universitet, 2012. s. 72
Serie
Umeå University medical dissertations, ISSN 0346-6612 ; 1505
Nyckelord
Arterial Pulsatility, cerebrospinal fluid, cerebral blood flow, venous flow, intracranial pressure, pulse pressure, dementia, hippocampus, multiple sclerosis, magnetic resonance imaging
Nationell ämneskategori
Medicinteknik
Forskningsämne
radiofysik
Identifikatorer
urn:nbn:se:umu:diva-55424 (URN)978-91-7459-428-7 (ISBN)
Disputation
2012-06-08, Bergasalen, by 27, Norrlands universitetssjukhus, Umeå, 13:00 (Engelska)
Opponent
Handledare
Forskningsfinansiär
Vetenskapsrådet, 621-2011-5216
Tillgänglig från: 2012-05-16 Skapad: 2012-05-14 Senast uppdaterad: 2018-06-08Bibliografiskt granskad

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