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Birgander, Richard
Publications (10 of 30) Show all publications
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
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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.

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: 2018-03-15Bibliographically 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?
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2014 (English)In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 41, no 10, p. 101903-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
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2014 (English)In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 35, no 2, p. 365-372Article 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
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2013 (English)In: Nuclear medicine communications, ISSN 0143-3636, E-ISSN 1473-5628, Vol. 34, no 10, p. 978-989Article 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)000323884800007 ()
Projects
NYPUMPROSPUM
Note

Originally published in thesis in manuscript form.

Available from: 2013-05-12 Created: 2013-05-12 Last updated: 2018-01-26Bibliographically 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
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2013 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 3, p. 498-504Article 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: 2018-03-15Bibliographically 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
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2013 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 54, no 4, p. 2738-2745Article 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
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2013 (English)In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 19, no 4, p. 469-471Article 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
Lenfeldt, N., Hansson, W., Larsson, A., Nyberg, L., Birgander, R. & Forsgren, L. (2013). Diffusion tensor imaging and correlations to Parkinson rating scales. Journal of Neurology, 260(11), 2823-2830
Open this publication in new window or tab >>Diffusion tensor imaging and correlations to Parkinson rating scales
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2013 (English)In: Journal of Neurology, ISSN 0340-5354, E-ISSN 1432-1459, Vol. 260, no 11, p. 2823-2830Article in journal (Refereed) Published
Abstract [en]

The contribution of various brain areas to the overall progression of Parkinson's disease remains to be determined. In this study, we apply MRI diffusion tensor imaging to investigate how alterations in diffusion relate to phenotype and symptoms measured by clinical rating scales. Sixty-four patients were investigated at baseline and three follow-ups (1, 3 and 5 years). Thirty-six patients remained in the last follow-up. Regions of interests included frontal white matter, basal ganglia, thalamus, and cerebellum. Scoring on the Unified Parkinson's Disease Rating Scale (UPDRS) I, II, III, Hoehn and Yahr (HY) scale and the Schwab and England scale (SE) was determined. Mean, radial, and axial diffusion and fractional anisotropy were modeled with phenotype and clinical scales in a multivariate/univariate analysis correcting for other covariates. Significance was set at 0.05 Bonferroni corrected. All rating scales except UPDRS III significantly correlated to the diffusion measures, as did clinical phenotype. Specifically, putamen, globus pallidus, and thalamus demonstrated higher diffusion with worsening scores. Diffusion in thalamus was higher in the tremor dominant phenotype than in postural imbalance and gait disturbance. Decline in overall functionality (UPDRS II and SE scale), including mental status (UPDRS I) and stage of the disease (HY scale), in Parkinson's disease is related to altered diffusion in the lentiform nucleus and thalamus. Motor function is not mirrored in diffusion changes, possibly due to medication. Tremor dominant PD patients show diffusion alterations in the thalamus, but the significance of this for tremor generation remains to be determined.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2013
Keyword
Parkinson's disease, MRI, Thalamus, UPDRS, Phenotype
National Category
Neurology Neurosciences
Identifiers
urn:nbn:se:umu:diva-83625 (URN)10.1007/s00415-013-7080-2 (DOI)000326400800015 ()
Funder
Swedish Research Council
Available from: 2013-12-05 Created: 2013-12-03 Last updated: 2018-03-15Bibliographically approved
Wåhlin, A., Ambarki, K., Birgander, R., Wieben, O., Johnson, K., Malm, J. & Eklund, A. (2013). Measuring pulsatile flow in cerebral arteries using 4D phase-contrast magnetic resonance imaging. American Journal of Neuroradiology, 34(9), 1740-1745
Open this publication in new window or tab >>Measuring pulsatile flow in cerebral arteries using 4D phase-contrast magnetic resonance imaging
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2013 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 34, no 9, p. 1740-1745Article 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
Ambarki, K., Lindqvist, T., Wåhlin, A., Petterson, E., Warntjes, J., Birgander, R., . . . Eklund, A. (2012). Evaluation of automatic measurement of the intracranial volume based on quantitative MR imaging. American Journal of Neuroradiology, 33(10), 1951-1956
Open this publication in new window or tab >>Evaluation of automatic measurement of the intracranial volume based on quantitative MR imaging
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2012 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 33, no 10, p. 1951-1956Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Brain size is commonly described in relation to ICV, whereby accurate assessment of this quantity is fundamental. Recently, an optimized MR sequence (QRAPMASTER) was developed for simultaneous quantification of T1, T2, and proton density. ICV can be measured automatically within minutes from QRAPMASTER outputs and a dedicated software, SyMRI. Automatic estimations of ICV were evaluated against the manual segmentation.

MATERIALS AND METHODS: In 19 healthy subjects, manual segmentation of ICV was performed by 2 neuroradiologists (Obs1, Obs2) by using QBrain software and conventional T2-weighted images. The automatic segmentation from the QRAPMASTER output was performed by using SyMRI. Manual corrections of the automatic segmentation were performed (corrected-automatic) by Obs1 and Obs2, who were blinded from each other. Finally, the repeatability of the automatic method was evaluated in 6 additional healthy subjects, each having 6 repeated QRAPMASTER scans. The time required to measure ICV was recorded.

RESULTS: No significant difference was found between reference and automatic (and corrected-automatic) ICV (P > .25). The mean difference between the reference and automatic measurement was -4.84 ± 19.57 mL (or 0.31 ± 1.35%). Mean differences between the reference and the corrected-automatic measurements were -0.47 ± 17.95 mL (-0.01 ± 1.24%) and -1.26 ± 17.68 mL (-0.06 ± 1.22%) for Obs1 and Obs2, respectively. The repeatability errors of the automatic and the corrected-automatic method were <1%. The automatic method required 1 minute 11 seconds (SD = 12 seconds) of processing. Adding manual corrections required another 1 minute 32 seconds (SD = 38 seconds).

CONCLUSIONS: Automatic and corrected-automatic quantification of ICV showed good agreement with the reference method. SyMRI software provided a fast and reproducible measure of ICV.

National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-55635 (URN)10.3174/ajnr.A3067 (DOI)000311711400020 ()22555574 (PubMedID)
Available from: 2012-05-25 Created: 2012-05-25 Last updated: 2018-03-15Bibliographically approved
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