umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Birgander, Richard
Publications (10 of 33) Show all publications
Dunås, T., Wahlin, 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
Show others...
2016 (English)In: Magnetic Resonance Materials in Physics, Biology and Medicine, ISSN 0968-5243, E-ISSN 1352-8661, Vol. 29, no 1, 39-47 p.Article 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.

Keyword
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: 2017-11-30Bibliographically approved
Zarrinkoob, L., Ambarki, K., Wahlin, 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
Show others...
2015 (English)In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 35, no 4, 648-654 p.Article 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.

Keyword
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: 2017-12-04Bibliographically approved
Lenfeldt, N., Larsson, A., Nyberg, L., Birgander, R. & Forsgren, L. (2015). Fractional anisotropy in the substantia nigra in Parkinson's disease: a complex picture. European Journal of Neurology, 22(10), 1410-1416.
Open this publication in new window or tab >>Fractional anisotropy in the substantia nigra in Parkinson's disease: a complex picture
Show others...
2015 (English)In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 22, no 10, 1410-1416 p.Article in journal (Refereed) Published
Abstract [en]

Background and purpose: This study employs magnetic resonance imaging (MRI) diffusion tensor imaging to compare diffusion measures in the brains of patients with Parkinson's disease (PD) with healthy controls using longitudinal data. Methods: One-hundred and twenty-two patients and 34 controls were included at baseline. The MRI investigations were repeated after 1, 3 and 5 years. The diffusion measures were quantified using fractional anisotropy and mean, radial and axial diffusion (FA, MD, RD, AD). Regions of interest included the anterior, middle and posterior substantia nigra (SN), but also other areas. Linear models were used to test for the effect of disease and hemispheric lateralization. The P value was set at 0.05 (Bonferroni corrected). Results: Fractional anisotropy and AD were increased in the three nigral subareas in PD (P < 0.01), but MD and RD were unaltered. The right SN had higher FA than the left in all subareas (P < 0.01). MD and AD were increased in the right anterior part (P < 0.04), whereas MD and RD were decreased in the right middle and posterior parts (P < 0.001). The left middle cerebellar peduncle had increased FA and AD (P < 0.001) and decreased MD and RD (P < 0.01) compared to the right. Diffusion measures did not progress over time and side differences were not related to disease or lateralization of symptoms. Conclusions: Increased FA in the SN in PD indicates gliosis and inflammation in the nuclei, but possibly also intrusion of surrounding fibres into the shrinking structure. The hemispheric side differences of diffusion might reflect natural lateralization of connectivity, but their relation to PD must be studied further.

Keyword
diffusion imaging, fractional anisotropy, lateralization, Parkinson, substantia nigra
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-111012 (URN)10.1111/ene.12760 (DOI)000362672700012 ()26118635 (PubMedID)
Available from: 2015-11-04 Created: 2015-11-02 Last updated: 2017-05-10Bibliographically approved
Vågberg, M., Norgren, N., Dring, A., Lindqvist, T., Birgander, R., Zetterberg, H. & Svenningsson, A. (2015). Levels and Age Dependency of Neurofilament Light and Glial Fibrillary Acidic Protein in Healthy Individuals and Their Relation to the Brain Parenchymal Fraction. PLoS ONE, 10(8), Article ID e0135886.
Open this publication in new window or tab >>Levels and Age Dependency of Neurofilament Light and Glial Fibrillary Acidic Protein in Healthy Individuals and Their Relation to the Brain Parenchymal Fraction
Show others...
2015 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 8, e0135886Article in journal (Refereed) Published
Abstract [en]

Background Neurofilament light (NFL) and Glial Fibrillary Acidic Protein (GFAP) are integral parts of the axonal and astrocytal cytoskeletons respectively and are released into the cerebrospinal fluid (CSF) in cases of cellular damage. In order to interpret the levels of these biomarkers in disease states, knowledge on normal levels in the healthy is required. Another biomarker for neurodegeneration is brain atrophy, commonly measured as brain parenchymal fraction (BPF) using magnetic resonance imaging (MRI). Potential correlations between levels of NFL, GFAP and BPF in healthy individuals have not been investigated. Objectives To present levels of NFL and GFAP in healthy individuals stratified for age, and investigate the correlation between them as well as their correlation with BPF. Methods The CSF was analysed in 53 healthy volunteers aged 21 to 70 (1 sample missing for GFAP analysis) and 48 of the volunteers underwent determination of BPF using MRI. Results Mean (+/- SD) NFL was 355 ng/L (+/- 214), mean GFAP was 421 ng/L (+/- 129) and mean BPF was 0.867 (+/- 0.035). All three biomarkers correlated with age. NFL also correlated with both GFAP and BPF. When controlled for age, only the correlation between NFL and GFAP retained statistical significance. Conclusions This study presents data on age-stratified levels of NFL and GFAP in the CSF of healthy individuals. There is a correlation between levels of NFL and GFAP and both increase with age. A correlation between NFL and BPF was also found, but did not retain statistical significance if controlled for age.

Place, publisher, year, edition, pages
PLOS one, 2015
National Category
Neurosciences
Identifiers
urn:nbn:se:umu:diva-109378 (URN)10.1371/journal.pone.0135886 (DOI)000360299100048 ()26317831 (PubMedID)
Available from: 2015-09-29 Created: 2015-09-25 Last updated: 2018-01-11Bibliographically approved
Brynolfsson, P., Nilsson, D., Henriksson, R., Hauksson, J., Karlsson, M., Garpebring, A., . . . Asklund, T. (2014). ADC texture-An imaging biomarker for high-grade glioma?. Medical physics (Lancaster), 41(10), 101903.
Open this publication in new window or tab >>ADC texture-An imaging biomarker for high-grade glioma?
Show others...
2014 (English)In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 41, no 10, 101903- p.Article in journal (Refereed) Published
Abstract [en]

Purpose:

Survival for high-grade gliomas is poor, at least partly explained by intratumoral heterogeneity contributing to treatment resistance. Radiological evaluation of treatment response is in most cases limited to assessment of tumor size months after the initiation of therapy. Diffusion-weighted magnetic resonance imaging (MRI) and its estimate of the apparent diffusion coefficient (ADC) has been widely investigated, as it reflects tumor cellularity and proliferation. The aim of this study was to investigate texture analysis of ADC images in conjunction with multivariate image analysis as a means for identification of pretreatment imaging biomarkers.

Methods:

Twenty-three consecutive high-grade glioma patients were treated with radiotherapy (2 Gy/60 Gy) with concomitant and adjuvant temozolomide. ADC maps and T1-weighted anatomical images with and without contrast enhancement were collected prior to treatment, and (residual) tumor contrast enhancement was delineated. A gray-level co-occurrence matrix analysis was performed on the ADC maps in a cuboid encapsulating the tumor in coronal, sagittal, and transversal planes, giving a total of 60 textural descriptors for each tumor. In addition, similar examinations and analyses were performed at day 1, week 2, and week 6 into treatment. Principal component analysis (PCA) was applied to reduce dimensionality of the data, and the five largest components (scores) were used in subsequent analyses. MRI assessment three months after completion of radiochemotherapy was used for classifying tumor progression or regression.

Results:

The score scatter plots revealed that the first, third, and fifth components of the pretreatment examinations exhibited a pattern that strongly correlated to survival. Two groups could be identified: one with a median survival after diagnosis of 1099 days and one with 345 days, p = 0.0001.

Conclusions:

By combining PCA and texture analysis, ADC texture characteristics were identified, which seems to hold pretreatment prognostic information, independent of known prognostic factors such as age, stage, and surgical procedure. These findings encourage further studies with a larger patient cohort. (C) 2014 Author(s).

Keyword
texture analysis, glioma, multivariate image analysis, ADC
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:umu:diva-96625 (URN)10.1118/1.4894812 (DOI)000343032400019 ()
Available from: 2014-11-27 Created: 2014-11-24 Last updated: 2017-12-05Bibliographically approved
Wåhlin, A., Ambarki, K., Birgander, R., Malm, J. & Eklund, A. (2014). Intracranial pulsatility is associated with regional brain volume in elderly individuals. Neurobiology of Aging, 35(2), 365-372.
Open this publication in new window or tab >>Intracranial pulsatility is associated with regional brain volume in elderly individuals
Show others...
2014 (English)In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 35, no 2, 365-372 p.Article in journal (Refereed) Published
Abstract [en]

Excessive intracranial pulsatility is thought to damage the cerebral microcirculation, causing cognitive decline in elderly individuals. We investigated relationships between brain structure and measures related to intracranial pulsatility among healthy elderly. Thirty-seven stroke-free, non-demented individuals (62-82 years of age) were included. We assessed brain structure, invasively measured cerebrospinal fluid (CSF) pulse pressure, and magnetic resonance-quantified arterial and CSF flow pulsatility, as well as arterial pulse pressure. Using both multivariate partial least squares and ordinary regression analyses, we identified a significant pattern of negative relationships between the volume of several brain regions and measures of intracranial pulsatility. The strongest relationships concerned the temporal lobe cortex and hippocampus. These findings were also coherent with observations of positive relationships between intracranial pulsatility and ventricular volume. In conclusion, elderly subjects with high intracranial pulsatility display smaller brain volume and larger ventricles, supporting the notion that excessive cerebral arterial pulsatility harms the brain. This calls for research investigating altered intracranial cardiac-related pulsatile stress as a potential risk factor that may cause or worsen the prognosis in subjects developing cognitive impairment and dementia.

National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-98388 (URN)10.1016/j.neurobiolaging.2013.08.026 (DOI)000328655600011 ()24080175 (PubMedID)
Available from: 2015-01-21 Created: 2015-01-21 Last updated: 2017-12-05Bibliographically approved
Jakobson Mo, S., Larsson, A., Linder, J., Birgander, R., Edenbandt, L., Stenlund, H., . . . Riklund, K. (2013). 123I-FP-Cit and 123I-IBZM SPECT uptake in a prospective normal material analysed with two different semi-quantitative image evaluation tools. Nuclear medicine communications, 34(10), 978-989.
Open this publication in new window or tab >>123I-FP-Cit and 123I-IBZM SPECT uptake in a prospective normal material analysed with two different semi-quantitative image evaluation tools
Show others...
2013 (English)In: Nuclear medicine communications, ISSN 0143-3636, E-ISSN 1473-5628, Vol. 34, no 10, 978-989 p.Article in journal (Refereed) Published
Abstract [en]

Objective: The need for age-adjusted and/or sex-adjusted reference values in dopamine transporter (DAT) and dopamine D2 receptor (D2R) imaging with single-photon emission computed tomography (SPECT) in a longitudinal study of parkinsonian diseases was investigated. We used two different image evaluation tools with a cross-sectional and longitudinal statistical approach.

Materials and methods: Baseline DAT and/or D2R SPECT were performed in 51 healthy controls (HC), age-matched to patients in an ongoing prospective study on idiopathic parkinsonism. Twenty-four HC were re-examined after 3 years and 21 HC were examined again after 5 years. SPECT was performed with I-123-FP-Cit and I-123-IBZM on a two-headed hybrid gamma camera. Regions of interest and volumes of interest (VOIs) were used for image evaluation. A cross-sectional and longitudinal statistical analysis was carried out.

Results: Fewer sex-based differences and less age dependency were seen in DAT SPECT uptake ratios compared with D2R SPECT uptake ratios and when comparing uptake ratios obtained with regions of interest against those with VOIs. In the cross-sectional analysis, a significant age-dependent decline was seen in women in both DAT and D2R uptakes with the VOI method but not in men with either evaluation method. In the longitudinal dataset, both a slight decline and increase over time were seen in DAT uptake; however, a general pattern of decrease was seen in both men and women in D2R uptake.

Conclusion: The choice of the image evaluation method can influence the pattern of sex-based and age-related differences. The results speak for the use of age-stratified reference values for women, in particular when using a VOI method.

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2013
Keyword
123I-FP-CIT, 123I-IBZM, ageing, dopamine, sex, prospective, single-photon emission computed tomography
National Category
Radiology, Nuclear Medicine and Medical Imaging
Research subject
Radiology
Identifiers
urn:nbn:se:umu:diva-70273 (URN)10.1097/MNM.0b013e328364aa2e (DOI)
Projects
NYPUMPROSPUM
Note

Originally published in thesis in manuscript form

Available from: 2013-05-12 Created: 2013-05-12 Last updated: 2017-12-06Bibliographically approved
Vågberg, M., Lindqvist, T., Ambarki, K., Warntjes, J. B., Sundström, P., Birgander, R. & Svenningsson, A. (2013). Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis. American Journal of Neuroradiology, 34(3), 498-504.
Open this publication in new window or tab >>Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis
Show others...
2013 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 3, 498-504 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Brain atrophy is a manifestation of tissue damage in MS. Reduction in brain parenchymal fraction is an accepted marker of brain atrophy. In this study, the approach of synthetic tissue mapping was applied, in which brain parenchymal fraction was automatically calculated based on absolute quantification of the tissue relaxation rates R1 and R2 and the proton attenuation. MATERIALS AND METHODS: The BPF values of 99 patients with MS and 35 control subjects were determined by using SyMap and tested in relationship to clinical variables. A subset of 5 patients with MS and 5 control subjects were also analyzed with a manual segmentation technique as a reference. Reproducibility of SyMap was assessed in a separate group of 6 healthy subjects, each scanned 6 consecutive times. RESULTS: Patients with MS had significantly lower BPF (0.852 0.0041, mean +/- SE) compared with control subjects (0.890 +/- 0.0040). Significant linear relationships between BPF and age, disease duration, and Expanded Disability Status Scale scores were observed (P < .001). A strong correlation existed between SyMap and the reference method (r = 0.96; P < .001) with no significant difference in mean BPF. Coefficient of variation of repeated SyMap BPF measurements was 0.45%. Scan time was <6 minutes, and postprocessing time was <2 minutes. CONCLUSIONS: SyMap is a valid and reproducible method for determining BPF in MS within a clinically acceptable scan time and postprocessing time. Results are highly congruent with those described using other methods and show high agreement with the manual reference method.

National Category
Neurology Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-86086 (URN)10.3174/ajnr.A3262 (DOI)000329846900009 ()
Available from: 2014-02-17 Created: 2014-02-17 Last updated: 2017-12-06Bibliographically approved
Ambarki, K., Hallberg, P., Jóhannesson, G., Lindén, C., Zarrinkoob, L., Wåhlin, A., . . . Eklund, A. (2013). Blood flow of ophthalmic artery in healthy individuals determined by phase-contrast magnetic resonance imaging. Investigative Ophthalmology and Visual Science, 54(4), 2738-2745.
Open this publication in new window or tab >>Blood flow of ophthalmic artery in healthy individuals determined by phase-contrast magnetic resonance imaging
Show others...
2013 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 54, no 4, 2738-2745 p.Article in journal (Refereed) Published
Abstract [en]

PURPOSE: Recent development of magnetic resonance imaging (MRI) offers new possibilities to assess ocular blood flow. This prospective study evaluates the feasibility of phase-contrast MRI (PCMRI) to measure flow rate in the ophthalmic artery (OA) and establish reference values in healthy young (HY) and elderly (HE) subjects.

METHODS: Fifty HY subjects (28 females, 21-30 years of age) and 44 HE (23 females, 64-80 years of age) were scanned on a 3-Tesla MR system. The PCMRI sequence had a spatial resolution of 0.35 mm per pixel, with the measurement plan placed perpendicularly to the OA. Mean flow rate (Qmean), resistive index (RI), and arterial volume pulsatility of OA (ΔVmax) were measured from the flow rate curve. Accuracy of PCMRI measures was investigated using a vessel-phantom mimicking the diameter and the flow rate range of the human OA.

RESULTS: Flow rate could be assessed in 97% of the OAs. Phantom investigations showed good agreement between the reference and PCMRI measurements with an error of <7%. No statistical difference was found in Qmean between HY and HE individuals (HY: mean ± SD = 10.37 ± 4.45 mL/min; HE: 10.81 ± 5.15 mL/min, P = 0.655). The mean of ΔVmax (HY: 18.70 ± 7.24 μL; HE: 26.27 ± 12.59 μL, P < 0.001) and RI (HY: 0.62 ± 0.08; HE: 0.67 ± 0.1, P = 0.012) were significantly different between HY and HE.

CONCLUSIONS: This study demonstrated that the flow rate of OA can be quantified using PCMRI. There was an age difference in the pulsatility parameters; however, the mean flow rate appeared independent of age. The primary difference in flow curves between HE and HY was in the relaxation phase of the systolic peak.

Keyword
magnetic resonance imaging, blood flow, ophthalmic artery
National Category
Ophthalmology
Identifiers
urn:nbn:se:umu:diva-73723 (URN)10.1167/iovs.13-11737 (DOI)000319821700039 ()23518769 (PubMedID)
Available from: 2013-06-27 Created: 2013-06-27 Last updated: 2017-12-06Bibliographically approved
Lenfeldt, N., Larsson, A., Nyberg, L., Birgander, R. & Forsgren, L. (2013). Diffusion measures in early stage parkinsonism: controversial findings including hemispheric lateralisation [Letter to the editor]. Parkinsonism & Related Disorders, 19(4), 469-471.
Open this publication in new window or tab >>Diffusion measures in early stage parkinsonism: controversial findings including hemispheric lateralisation
Show others...
2013 (English)In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 19, no 4, 469-471 p.Article in journal, Letter (Refereed) Published
Keyword
Parkinson's disease, MRI, Anisotropy, Substantia nigra, Middle cerebellar peduncle
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-71098 (URN)10.1016/j.parkreldis.2012.10.003 (DOI)000317455600017 ()
Available from: 2013-06-12 Created: 2013-05-20 Last updated: 2017-12-06Bibliographically approved
Organisations

Search in DiVA

Show all publications