umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects
Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
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. 

Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2012. , 72 p.
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1505
Keyword [en]
Arterial Pulsatility, cerebrospinal fluid, cerebral blood flow, venous flow, intracranial pressure, pulse pressure, dementia, hippocampus, multiple sclerosis, magnetic resonance imaging
National Category
Medical Engineering
Research subject
radiofysik
Identifiers
URN: urn:nbn:se:umu:diva-55424ISBN: 978-91-7459-428-7 (print)OAI: oai:DiVA.org:umu-55424DiVA: diva2:526678
Public defence
2012-06-08, Bergasalen, by 27, Norrlands universitetssjukhus, Umeå, 13:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 621-2011-5216
Available from: 2012-05-16 Created: 2012-05-14 Last updated: 2015-10-01Bibliographically approved
List of papers
1. Phase contrast MRI quantification of pulsatile volumes of brain arteries, veins, and cerebrospinal fluids compartments: repeatability and physiological interactions
Open this publication in new window or tab >>Phase contrast MRI quantification of pulsatile volumes of brain arteries, veins, and cerebrospinal fluids compartments: repeatability and physiological interactions
Show others...
2012 (English)In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 35, no 5, 1055-1062 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To study measurement repeatability and physiological determinants on measurement stability for phase contrast MRI (PC-MRI) measurements of cyclic volume changes (ΔV) of brain arteries, veins, and cerebrospinal fluid (CSF) compartments.

MATERIALS AND METHODS: Total cerebral blood flow (tCBF), total internal jugular flow (tJBF) and spinal CSF flow at C2-C3 level and CSF in the aqueduct was measured using five repetitions in 20 healthy subjects. After subtracting net flow, waveforms were integrated to calculate ΔV of arterial, venous, and cerebrospinal fluid compartments. The intraclass correlation coefficient (ICC) was used to measure repeatability. Systematic errors were investigated by a series of phantom measurements.

RESULTS: For ΔV calculated from tCBF, tJBF and both CSF waveforms, the ICC was ≥0.85. ΔV from the tCBF waveform decreased linearly between repetitions (P = 0.012). Summed CSF and venous volume being shifted out from the cranium was correlated with ΔV calculated from the tCBF waveform (r = 0.75; P < 0.001). Systematic errors increased at resolutions <4 pixels per diameter.

CONCLUSION: Repeatability of ΔV calculated from tCBF, tJBF, and CSF waveforms allows useful interpretations. The subject's time in the MR system and imaging resolution should be considered when interpreting volume changes. Summed CSF and venous volume changes was associated with arterial volume changes.

J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

Place, publisher, year, edition, pages
John Wiley & Sons, 2012
Keyword
brain, blood, cerebrospinal fluid, flow, volume changes, repeatability
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-50992 (URN)10.1002/jmri.23527 (DOI)000302721800007 ()22170792 (PubMedID)
Note
Kompletteras 2012-09Available from: 2012-01-04 Created: 2012-01-04 Last updated: 2017-12-08Bibliographically approved
2. Assessment of craniospinal pressure-volume indices
Open this publication in new window or tab >>Assessment of craniospinal pressure-volume indices
Show others...
2010 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 31, no 9, 1645-1650 p.Article in journal (Refereed) 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.

Identifiers
urn:nbn:se:umu:diva-36883 (URN)10.3174/ajnr.A2166 (DOI)000283011300019 ()20595369 (PubMedID)
Available from: 2010-10-13 Created: 2010-10-13 Last updated: 2017-12-12Bibliographically approved
3. Venous and cerebrospinal fluid flow in multiple sclerosis. A case-control study.
Open this publication in new window or tab >>Venous and cerebrospinal fluid flow in multiple sclerosis. A case-control study.
Show others...
2010 (English)In: Annals of Neurology, ISSN 0364-5134, E-ISSN 1531-8249, Vol. 68, no 2, 255-259 p.Article in journal (Refereed) Published
Abstract [en]

The prevailing view on multiple sclerosis etiopathogenesis has been challenged by the suggested new entity chronic cerebrospinal venous insufficiency. To test this hypothesis, we studied 21 relapsing-remitting multiple sclerosis cases and 20 healthy controls with phase-contrast magnetic resonance imaging. In addition, in multiple sclerosis cases we performed contrast-enhanced magnetic resonance angiography. We found no differences regarding internal jugular venous outflow, aqueductal cerebrospinal fluid flow, or the presence of internal jugular blood reflux. Three of 21 cases had internal jugular vein stenoses. In conclusion, we found no evidence confirming the suggested vascular multiple sclerosis hypothesis.

Place, publisher, year, edition, pages
Wiley, 2010
National Category
Neurology
Research subject
Neurology
Identifiers
urn:nbn:se:umu:diva-35616 (URN)10.1002/ana.22132 (DOI)000280721500020 ()20695018 (PubMedID)
Available from: 2010-08-26 Created: 2010-08-26 Last updated: 2017-12-12Bibliographically approved
4. In healthy elderly the volumes of several brain regions are related to pulsatility in cerebral arteries and cerebrospinal fluid
Open this publication in new window or tab >>In healthy elderly the volumes of several brain regions are related to pulsatility in cerebral arteries and cerebrospinal fluid
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-55475 (URN)
Available from: 2012-05-16 Created: 2012-05-16 Last updated: 2015-10-01Bibliographically approved
5. Measuring pulsatile flow in cerebral arteries using 4D phase-contrast magnetic resonance imaging
Open this publication in new window or tab >>Measuring pulsatile flow in cerebral arteries using 4D phase-contrast magnetic resonance imaging
Show others...
2013 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 9, 1740-1745 p.Article in journal (Other academic) Published
Abstract [en]

BACKGROUND AND PURPOSE: 4D PCMRI can be used to quantify pulsatile hemodynamics in multiple cerebral arteries. The aim of this study was to compare 4D PCMRI and 2D PCMRI for assessments of pulsatile hemodynamics in major cerebral arteries. MATERIALS AND METHODS: We scanned the internal carotid artery, the anterior cerebral artery, the basilar artery, and the middle cerebral artery in 10 subjects with a single 4D and multiple 2D PCMRI acquisitions by use of a 3T system and a 32-channel head coil. We assessed the agreement regarding net flow and the volume of arterial pulsatility (V) for all vessels. RESULTS: 2D and 4D PCMRI produced highly correlated results, with r = 0.86 and r = 0.95 for V and net flow, respectively (n = 69 vessels). These values increased to r = 0.93 and r = 0.97, respectively, during investigation of a subset of measurements with <5% variation in heart rate between the 4D and 2D acquisition (n = 31 vessels). Significant differences were found for ICA and MCA net flow (P = .004 and P < .001, respectively) and MCA V (P = .006). However, these differences were attenuated and no longer significant when the subset with stable heart rate (n = 31 vessels) was analyzed. CONCLUSIONS: 4D PCMRI provides a powerful methodology to measure pulsatility of the larger cerebral arteries from a single acquisition. A large part of differences between measurements was attributed to physiologic variations. The results were consistent with 2D PCMRI.

National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-55477 (URN)10.3174/ajnr.A3442 (DOI)000329848800020 ()
Available from: 2012-05-16 Created: 2012-05-16 Last updated: 2017-12-07Bibliographically approved

Open Access in DiVA

fulltext(4066 kB)582 downloads
File information
File name FULLTEXT01.pdfFile size 4066 kBChecksum SHA-512
732b9e1920833081f4da7c1431ad065779205c2be9d80b063206fb2ef935af9ba3e8dda1d191eed7b59c834249241cef73f1bdebd3cfb4690522b9d17014192c
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Wåhlin, Anders
By organisation
Radiation Physics
Medical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 582 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1207 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf