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Birgander, Richard
Publications (10 of 43) Show all publications
Zarrinkoob, L., Wåhlin, A., Ambarki, K., Birgander, R., Eklund, A. & Malm, J. (2019). Blood flow lateralization and collateral compensatory mechanisms in patients with carotid artery stenosis. Stroke, 50(5), 1081-1088
Open this publication in new window or tab >>Blood flow lateralization and collateral compensatory mechanisms in patients with carotid artery stenosis
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2019 (English)In: Stroke, ISSN 0039-2499, E-ISSN 1524-4628, Vol. 50, no 5, p. 1081-1088Article in journal (Refereed) Published
Abstract [en]

Background and Purpose: Four-dimensional phase-contrast magnetic resonance imaging enables quantification of blood flow rate (BFR; mL/min) in multiple cerebral arteries simultaneously, making it a promising technique for hemodynamic investigation in patients with stroke. The aim of this study was to quantify the hemodynamic disturbance and the compensatory pattern of collateral flow in patients with symptomatic carotid stenosis.

Methods: Thirty-eight patients (mean, 72 years; 27 men) with symptomatic carotid stenosis (>/=50%) or occlusion were investigated using 4-dimensional phase-contrast magnetic resonance imaging. For each patient, BFR was measured in 19 arteries/locations. The ipsilateral side to the symptomatic carotid stenosis was compared with the contralateral side.

Results: Internal carotid artery BFR was lower on the ipsilateral side (134+/-87 versus 261+/-95 mL/min; P<0.001). BFR in anterior cerebral artery (A1 segment) was lower on ipsilateral side (35+/-58 versus 119+/-72 mL/min; P<0.001). Anterior cerebral artery territory bilaterally was primarily supplied by contralateral internal carotid artery. The ipsilateral internal carotid artery mainly supplied the ipsilateral middle cerebral artery (MCA) territory. MCA was also supplied by a reversed BFR found in the ophthalmic and the posterior communicating artery routes on the ipsilateral side (-5+/-28 versus 10+/-28 mL/min, P=0.001, and -2+/-12 versus 6+/-6 mL/min, P=0.03, respectively). Despite these compensations, BFR in MCA was lower on the ipsilateral side, and this laterality was more pronounced in patients with severe carotid stenosis (>/=70%). Although comparing ipsilateral MCA BFR between stenosis groups (<70% and >/=70%), there was no difference ( P=0.95).

Conclusions: With a novel approach using 4-dimensional phase-contrast magnetic resonance imaging, we could simultaneously quantify and rank the importance of collateral routes in patients with carotid stenosis. An important observation was that contralateral internal carotid artery mainly secured the bilateral anterior cerebral artery territory. Because of the collateral recruitment, compromised BFR in MCA is not necessarily related to the degree of carotid stenosis. These findings highlight the importance of simultaneous investigation of the hemodynamics of the entire cerebral arterial tree.

Place, publisher, year, edition, pages
Philadelphia: Lippincott Williams & Wilkins, 2019
Keywords
carotid stenosis, circle of Willis, humans, magnetic resonance imaging, cine, middle cerebral artery
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:umu:diva-158003 (URN)10.1161/STROKEAHA.119.024757 (DOI)000469350000029 ()30943887 (PubMedID)
Funder
Swedish Research Council, 2015-05616Swedish Research Council, 2017-04949Västerbotten County CouncilSwedish Heart Lung Foundation, 20140592
Available from: 2019-04-10 Created: 2019-04-10 Last updated: 2019-06-17Bibliographically approved
Qvarlander, S., Ambarki, K., Wåhlin, A., Jacobsson, J., Birgander, R., Malm, J. & Eklund, A. (2017). Cerebrospinal fluid and blood flow patterns in idiopathic normal pressure hydrocephalus. Acta Neurologica Scandinavica, 135(5), 576-584
Open this publication in new window or tab >>Cerebrospinal fluid and blood flow patterns in idiopathic normal pressure hydrocephalus
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2017 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 135, no 5, p. 576-584Article in journal (Refereed) Published
Abstract [en]

Objectives: Increased aqueduct cerebrospinal fluid (CSF) flow pulsatility and, recently, a reversed CSF flow in the aqueduct have been suggested as hallmarks of idiopathic normal pressure hydrocephalus (INPH). However, these findings have not been adequately confirmed. Our objective was to investigate the flow of blood and CSF in INPH, as compared to healthy elderly, in order to clarify which flow parameters are related to the INPH pathophysiology.

Materials and Methods: Sixteen INPH patients (73 years) and 35 healthy subjects (72 years) underwent phase-contrast magnetic resonance imaging (MRI). Measurements included aqueduct and cervical CSF flow, total arterial inflow (tCBF; i.e. carotid + vertebral arteries), and internal jugular vein flow. Flow pulsatility, net flow, and flow delays were compared (multiple linear regression, correcting for sex and age).

Results: Aqueduct stroke volume was higher in INPH than healthy (148±95 vs 90±50 mL, P<.05). Net aqueduct CSF flow was similar in magnitude and direction. The cervical CSF stroke volume was lower (P<.05). The internal carotid artery net flow was lower in INPH (P<.05), although tCBF was not. No differences were found in internal jugular vein flow or flow delays.

Conclusions: The typical flow of blood and CSF in INPH was mainly characterized by increased CSF pulsatility in the aqueduct and reduced cervical CSF pulsatility. The direction of mean net aqueduct CSF flow was from the third to the fourth ventricle. Our findings may reflect the altered distribution of intracranial CSF volume in INPH, although the causality of these relationships is unclear.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
Keywords
aqueduct flow, cerebral blood flow, cerebrospinal fluid, dementia, normal pressure hydrocephalus, phase-contrast magnetic resonance imaging
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-131143 (URN)10.1111/ane.12636 (DOI)000400156400012 ()27388230 (PubMedID)
Funder
Swedish Research Council, 221-2011-5216
Available from: 2017-02-06 Created: 2017-02-06 Last updated: 2018-06-09Bibliographically approved
Vågberg, M., Axelsson, M., Birgander, R., Burman, J., Cananau, C., Forslin, Y., . . . Wikström, J. (2017). Guidelines for the use of magnetic resonance imaging in diagnosing and monitoring the treatment of multiple sclerosis: recommendations of the Swedish Multiple Sclerosis Association and the Swedish Neuroradiological Society. Acta Neurologica Scandinavica, 135(1), 17-24
Open this publication in new window or tab >>Guidelines for the use of magnetic resonance imaging in diagnosing and monitoring the treatment of multiple sclerosis: recommendations of the Swedish Multiple Sclerosis Association and the Swedish Neuroradiological Society
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2017 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 135, no 1, p. 17-24Article, review/survey (Refereed) Published
Abstract [en]

Multiple sclerosis (MS) is associated with inflammatory lesions in the brain and spinal cord. The detection of such inflammatory lesions using magnetic resonance imaging (MRI) is important in the consideration of the diagnosis and differential diagnoses of MS, as well as in the monitoring of disease activity and predicting treatment efficacy. Although there is strong evidence supporting the use of MRI for both the diagnosis and monitoring of disease activity, there is a lack of evidence regarding which MRI protocols to use, the frequency of examinations, and in what clinical situations to consider MRI examination. A national workshop to discuss these issues was held in Stockholm, Sweden, in August 2015, which resulted in a Swedish consensus statement regarding the use of MRI in the care of individuals with MS. The aim of this consensus statement is to provide practical advice for the use of MRI in this setting. The recommendations are based on a review of relevant literature and the clinical experience of workshop attendees. It is our hope that these recommendations will benefit individuals with MS and guide healthcare professionals responsible for their care.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
Keywords
guidelines, magnetic resonance imaging, multiple sclerosis, recommendations
National Category
Radiology, Nuclear Medicine and Medical Imaging Neurology
Identifiers
urn:nbn:se:umu:diva-129699 (URN)10.1111/ane.12667 (DOI)000389421400002 ()27558404 (PubMedID)
Available from: 2017-01-10 Created: 2017-01-09 Last updated: 2018-06-09Bibliographically approved
Zarrinkoob, L., Ambarki, K., Wåhlin, A., Birgander, R., Carlberg, B., Eklund, A. & Malm, J. (2016). Aging alters the dampening of pulsatile blood flow in cerebral arteries. Journal of Cerebral Blood Flow and Metabolism, 36(9), 1519-1527
Open this publication in new window or tab >>Aging alters the dampening of pulsatile blood flow in cerebral arteries
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2016 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 36, no 9, p. 1519-1527Article in journal (Refereed) Published
Abstract [en]

Excessive pulsatile flow caused by aortic stiffness is thought to be a contributing factor for several cerebrovascular diseases. The main purpose of this study was to describe the dampening of the pulsatile flow from the proximal to the distal cerebral arteries, the effect of aging and sex, and its correlation to aortic stiffness. Forty-five healthy elderly (mean age 71 years) and 49 healthy young (mean age 25 years) were included. Phase-contrast magnetic resonance imaging was used for measuring blood flow pulsatility index and dampening factor (proximal artery pulsatility index/distal artery pulsatility index) in 21 cerebral and extra-cerebral arteries. Aortic stiffness was measured as aortic pulse wave velocity. Cerebral arterial pulsatility index increased due to aging and this was more pronounced in distal segments of cerebral arteries. There was no difference in pulsatility index between women and men. Dampening of pulsatility index was observed in all cerebral arteries in both age groups but was significantly higher in young subjects than in elderly. Pulse wave velocity was not correlated with cerebral arterial pulsatility index. The increased pulsatile flow in elderly together with reduced dampening supports the pulse wave encephalopathy theory, since it implies that a higher pulsatile flow is reaching distal arterial segments in older subjects.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-126505 (URN)10.1177/0271678X16629486 (DOI)000382996800004 ()26823470 (PubMedID)
Available from: 2016-10-27 Created: 2016-10-10 Last updated: 2019-05-09Bibliographically approved
Dunås, T., Wåhlin, A., Ambarki, K., Zarrinkoob, L., Birgander, R., Malm, J. & Eklund, A. (2016). Automatic labeling of cerebral arteries in magnetic resonance angiography. Magnetic Resonance Materials in Physics, Biology and Medicine, 29(1), 39-47
Open this publication in new window or tab >>Automatic labeling of cerebral arteries in magnetic resonance angiography
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2016 (English)In: Magnetic Resonance Materials in Physics, Biology and Medicine, ISSN 0968-5243, E-ISSN 1352-8661, Vol. 29, no 1, p. 39-47Article in journal (Refereed) Published
Abstract [en]

In order to introduce 4D flow magnetic resonance imaging (MRI) as a standard clinical instrument for studying the cerebrovascular system, new and faster postprocessing tools are necessary. The objective of this study was to construct and evaluate a method for automatic identification of individual cerebral arteries in a 4D flow MRI angiogram. Forty-six elderly individuals were investigated with 4D flow MRI. Fourteen main cerebral arteries were manually labeled and used to create a probabilistic atlas. An automatic atlas-based artery identification method (AAIM) was developed based on vascular-branch extraction and the atlas was used for identification. The method was evaluated by comparing automatic with manual identification in 4D flow MRI angiograms from 67 additional elderly individuals. Overall accuracy was 93 %, and internal carotid artery and middle cerebral artery labeling was 100 % accurate. Smaller and more distal arteries had lower accuracy; for posterior communicating arteries and vertebral arteries, accuracy was 70 and 89 %, respectively. The AAIM enabled fast and fully automatic labeling of the main cerebral arteries. AAIM functionality provides the basis for creating an automatic and powerful method to analyze arterial cerebral blood flow in clinical routine.

Keywords
Magnetic resonance angiography, Cerebral angiography, Circle of Willis, Atlases as topic, Automatic data processing
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-117830 (URN)10.1007/s10334-015-0512-5 (DOI)000370159800005 ()
Available from: 2016-04-05 Created: 2016-03-04 Last updated: 2018-06-07Bibliographically approved
Vågberg, M., Ambarki, K., Lindqvist, T., Birgander, R. & Svenningsson, A. (2016). Brain parenchymal fraction in an age-stratified healthy population: determined by MRI using manual segmentation and three automated segmentation methods. Journal of neuroradiology, 43(6), 384-391
Open this publication in new window or tab >>Brain parenchymal fraction in an age-stratified healthy population: determined by MRI using manual segmentation and three automated segmentation methods
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2016 (English)In: Journal of neuroradiology, ISSN 0150-9861, E-ISSN 1773-0406, Vol. 43, no 6, p. 384-391Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Brain atrophy is a prominent feature in many neurodegenerative diseases, such as multiple sclerosis, but age-related decrease of brain volume occurs regardless of pathological neurodegeneration. Changes in brain volume can be described by use of the brain parenchymal fraction (BPF), most often defined as the ratio of total brain parenchyma to total intracranial space. The BPF is of interest both in research and in clinical practice. To be able to properly interpret this variable, the normal range of BPF must be known. The objective of this study is to present normal values for BPF, stratified by age, and compare manual BPF measurement to three automated methods. MATERIALS AND METHODS: The BPFs of 106 healthy individuals aged 21 to 85 years were determined by the automated segmentation methods SyMap, VBM8 and SPM12. In a subgroup of 54 randomly selected individuals, the BPF was also determined by manual segmentation. RESULTS: The median (IQR) BPFs of the whole study population were 0.857 (0.064), 0.819 (0.028) and 0.784 (0.073) determined by SyMap, VBM8 and SPM12, respectively. The BPF decreased with increasing age. The correlation coefficients between manual segmentation and SyMap, VBM8 and SPM12 were 0.93 (P<0.001), 0.77 (P<0.001) and 0.56 (P<0.001), respectively. CONCLUSIONS: There was a clear relationship between increasing age and decreasing BPF. Knowledge of the range of normal BPF in relation to age group will help in the interpretation of BPF data. The automated segmentation methods displayed varying degrees of similarity to the manual reference, with SyMap being the most similar.

Place, publisher, year, edition, pages
Masson Editeur, 2016
Keywords
BPF, Brain atrophy, SPM, SyMap, VBM
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-128693 (URN)10.1016/j.neurad.2016.08.002 (DOI)000391158900004 ()27720265 (PubMedID)2-s2.0-84995584817 (Scopus ID)
Available from: 2016-12-12 Created: 2016-12-12 Last updated: 2018-06-09Bibliographically approved
Johansson, E., Ambarki, K., Birgander, R., Bahrami, N., Eklund, A. & Malm, J. (2016). Cerebral microbleeds in idiopathic normal pressure hydrocephalus. Fluids and Barriers of the CNS, 13, Article ID UNSP 4.
Open this publication in new window or tab >>Cerebral microbleeds in idiopathic normal pressure hydrocephalus
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2016 (English)In: Fluids and Barriers of the CNS, ISSN 2045-8118, E-ISSN 2045-8118, Vol. 13, article id UNSP 4Article in journal (Refereed) Published
Abstract [en]

Background: A vascular disease could be involved in pathophysiology of normal pressure hydrocephalus (INPH). If so, there should be an association between INPH and cerebral microbleeds (CMB). This study aims to analyze if CMB are associated with INPH.

Methods: In this case-control study we included 14 patients with INPH (mean age 76 years, 60 % female) and 41 healthy controls (HeCo; mean age 71 years, 60 % female). All were investigated with magnetic resonance imaging (MRI) using a T2*-sequence. The MRI exams were reviewed by two neuroradiologists for the presence of CMBs; the prevalence of findings of two or more CMBs was compared between INPH group and control group. After investigation, INPH patients underwent shunt surgery.

Results: Two or more CMB were detected more frequently in the INPH group compared to HeCo (n = 6, 43 % vs. n = 4, 10 %; p = 0.01). Among the participants where MRI revealed CMB, the number of CMB was higher among the INPH patients than the HeCo (median 8; IQR 2-34 vs. median 1; IQR 1-2; p = 0.005).

Conclusions: This study supports a vascular component to the pathophysiology of INPH.

Keywords
Idiopathic normal pressure hydrocephalus, Magnetic resonance imaging, Cerebral microbleeds
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-126799 (URN)10.1186/s12987-016-0028-z (DOI)000381859400001 ()26860218 (PubMedID)
Available from: 2016-11-01 Created: 2016-10-14 Last updated: 2018-06-09Bibliographically approved
Lenfeldt, N., Holmlund, H., Larsson, A., Birgander, R. & Forsgren, L. (2016). Frontal white matter injuries predestine gait difficulties in Parkinson's disease. Acta Neurologica Scandinavica, 134(3), 210-218
Open this publication in new window or tab >>Frontal white matter injuries predestine gait difficulties in Parkinson's disease
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2016 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 134, no 3, p. 210-218Article in journal (Refereed) Published
Abstract [en]

Objectives: This study applies diffusion tensor imaging (DTI) to determine differences in neuronal integrity between motor phenotypes in Parkinson's disease. Material and Methods: One hundred and twenty-two patients (47 females, mean age = 70.3 years) were included at baseline. Forty patients were tremor dominant (TD), 64 had postural imbalance and gait difficulty (PIGD), and 18 patients were indeterminate. The DTI was repeated after one, three and 5 years, including reassessment of phenotype. DTI was quantified using fractional anisotropy (FA), and mean, radial and axial diffusion. Targeted white matter involved six regions of interests (ROIs) in prefrontal cortex (PFC), the entrance to the external capsule (EEC) and lateral to the horn of the anterior ventricle (LVAH). Grey matter involved the basal ganglia. Data were analysed using mixed linear models with P < 0.05 (Bonferroni corrected) as significance threshold. Results: PIGD and Indeterminate had reduced FA and axial diffusion in PFC, EEC and LVAH compared to Tremor dominant (P < 0.05). Basal ganglia showed no differences. Post hoc analysis showed that FA correlated negatively, and mean and radial diffusion positively, to PIGD symptoms in EEC, LVAH and four ROIs in PFC (P < 0.05). Tremor symptoms showed no correlations. Patients converting to PIGD and Indeterminate had lower FA, and higher mean and radial diffusion, at baseline in EEC, LVAH and four areas in PFC compared to non-converting patients (P < 0.05). Conclusion: Degeneration in frontal white matter is connected to PIGD symptoms in Parkinson's disease and if present at an early stage, the risk for conversion to the PIGD phenotype increases.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
parkinsonism, diffusion tensor imaging, gait, tremor, anisotropy
National Category
Neurology Neurosciences
Identifiers
urn:nbn:se:umu:diva-125534 (URN)10.1111/ane.12532 (DOI)000381033500006 ()27465659 (PubMedID)
Available from: 2016-09-19 Created: 2016-09-13 Last updated: 2018-06-07Bibliographically approved
de Flon, P., Gunnarsson, M., Laurell, K., Söderström, L., Birgander, R., Lindqvist, T., . . . Svenningsson, A. (2016). Reduced inflammation in relapsing-remitting multiple sclerosis after therapy switch to rituximab. Neurology, 87(2), 141-147
Open this publication in new window or tab >>Reduced inflammation in relapsing-remitting multiple sclerosis after therapy switch to rituximab
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2016 (English)In: Neurology, ISSN 0028-3878, E-ISSN 1526-632X, Vol. 87, no 2, p. 141-147Article in journal (Refereed) Published
Abstract [en]

Objective: To describe the effects of switching treatment from ongoing first-line injectable therapies to rituximab on inflammatory activity measured by MRI and levels of CSF neurofilament light chain (CSF-NFL) in a cohort of patients with clinically stable relapsing-remitting multiple sclerosis (RRMS).

Method: Seventy-five patients with clinically stable RRMS treated with the first-line injectables interferon-β (IFN-β) and glatiramer acetate (GA) at 3 Swedish centers were switched to rituximab in this open-label phase II multicenter study. After a run-in period of 3 months, 2 IV doses of 1,000 mg rituximab were given 2 weeks apart followed by repeated clinical assessment, MRI, and CSF-NFL for 24 months.

Results: The mean cumulated number of gadolinium-enhancing lesions per patient at months 3 and 6 after treatment shift to rituximab was reduced compared to the run-in period (0.028 vs 0.36, p = 0.029). During the first year after treatment shift, the mean number of new or enlarged T2 lesions per patient was reduced (0.01 vs 0.28, p = 0.004) and mean CSF-NFL levels were reduced by 21% (p = 0.01).

Conclusions: For patients with RRMS, a treatment switch from IFN or GA to rituximab is associated with reduced inflammatory activity measured by MRI and CSF-NFL.

Classification of evidence: This study provides Class IV evidence that rituximab has an equal or superior effect in reducing inflammatory activity in RRMS measured by MRI and CSF-NFL compared to first-line injectables during the first year after treatment shift.

National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:umu:diva-127981 (URN)10.1212/WNL.0000000000002832 (DOI)000381470700032 ()27316241 (PubMedID)
Available from: 2016-12-05 Created: 2016-11-21 Last updated: 2018-06-09Bibliographically approved
Zarrinkoob, L., Ambarki, K., Wåhlin, A., Birgander, R., Eklund, A. & Malm, J. (2015). Blood flow distribution in cerebral arteries. Journal of Cerebral Blood Flow and Metabolism, 35(4), 648-654
Open this publication in new window or tab >>Blood flow distribution in cerebral arteries
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2015 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 35, no 4, p. 648-654Article in journal (Refereed) Published
Abstract [en]

High-resolution phase-contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra-and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717 +/- 123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21%; distal MCA, 6%; anterior cerebral artery (ACA), 12%, distal ACA, 4%; ophthalmic artery, 2%; posterior cerebral artery (PCA), 8%; and 20% to basilar artery. Deviating distributions were observed in subjects with 'fetal' PCA. Blood flow rate in cerebral arteries decreased with increasing age (P < 0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61 +/- 8; men: 55 +/- 6 mL/min/100 mL, P < 0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system.

Keywords
aging, cerebral blood flow, circle of Willis, cognitive impairment, phase-contrast MRI, stroke
National Category
Clinical Medicine
Identifiers
urn:nbn:se:umu:diva-103545 (URN)10.1038/jcbfm.2014.241 (DOI)000352027900015 ()25564234 (PubMedID)
Available from: 2015-05-25 Created: 2015-05-21 Last updated: 2019-05-09Bibliographically approved
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