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Wallin, E., Larsson, I.-M., Kristofferzon, M.-L., Larsson, E.-M., Raininko, R. & Rubertsson, S. (2018). Acute brain lesions on magnetic resonance imaging in relation to neurological outcome after cardiac arrest. Acta Anaesthesiologica Scandinavica, 62(5), 635-647
Open this publication in new window or tab >>Acute brain lesions on magnetic resonance imaging in relation to neurological outcome after cardiac arrest
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2018 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 62, no 5, p. 635-647Article in journal (Refereed) Published
Abstract [en]

BACKGROUND:

Magnetic resonance imaging (MRI) of the brain including diffusion-weighted imaging (DWI) is reported to have high prognostic accuracy in unconscious post-cardiac arrest (CA) patients. We documented acute MRI findings in the brain in both conscious and unconscious post-CA patients treated with target temperature management (TTM) at 32-34°C for 24 h as well as the relation to patients' neurological outcome after 6 months.

METHODS:

A prospective observational study with MRI was performed regardless of the level of consciousness in post-CA patients treated with TTM. Neurological outcome was assessed using the Cerebral Performance Categories scale and dichotomized into good and poor outcome.

RESULTS:

Forty-six patients underwent MRI at 3-5 days post-CA. Patients with good outcome had minor, mainly frontal and parietal, lesions. Acute hypoxic/ischemic lesions on MRI including DWI were more common in patients with poor outcome (P = 0.007). These lesions affected mostly gray matter (deep or cortical), with or without involvement of the underlying white matter. Lesions in the occipital and temporal lobes, deep gray matter and cerebellum showed strongest associations with poor outcome. Decreased apparent diffusion coefficient, was more common in patients with poor outcome.

CONCLUSIONS:

Extensive acute hypoxic/ischemic MRI lesions in the cortical regions, deep gray matter and cerebellum detected by visual analysis as well as low apparent diffusion coefficient values from quantitative measurements were associated with poor outcome. Patients with good outcome had minor hypoxic/ischemic changes, mainly in the frontal and parietal lobes.

National Category
Anesthesiology and Intensive Care
Identifiers
urn:nbn:se:uu:diva-340789 (URN)10.1111/aas.13074 (DOI)000429532400007 ()29363101 (PubMedID)
Available from: 2018-02-02 Created: 2018-02-02 Last updated: 2018-06-19Bibliographically approved
Olivo, G., Solstrand Dahlberg, L., Wiemerslage, L., Swenne, I., Zhukovsky, C., Salonen-Ros, H., . . . Schiöth, H. B. (2018). Atypical anorexia nervosa is not related to brain structural changes in newly diagnosed adolescent patients.. International Journal of Eating Disorders, 51(1), 39-45
Open this publication in new window or tab >>Atypical anorexia nervosa is not related to brain structural changes in newly diagnosed adolescent patients.
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2018 (English)In: International Journal of Eating Disorders, ISSN 0276-3478, E-ISSN 1098-108X, Vol. 51, no 1, p. 39-45Article in journal (Refereed) Published
Abstract [en]

OBJECTIVE: Patients with atypical anorexia nervosa (AN) have many features overlapping with AN in terms of genetic risk, age of onset, psychopathology and prognosis of outcome, although the weight loss may not be a core factor. While brain structural alterations have been reported in AN, there are currently no data regarding atypical AN patients.

METHOD: We investigated brain structure through a voxel-based morphometry analysis in 22 adolescent females newly-diagnosed with atypical AN, and 38 age- and sex-matched healthy controls (HC). ED-related psychopathology, impulsiveness and obsessive-compulsive traits were assessed with the Eating Disorder Examination Questionnaire (EDE-Q), Barratt Impulsiveness Scale (BIS-11) and Obsessive-compulsive Inventory Revised (OCI-R), respectively. Body mass index (BMI) was also calculated.

RESULTS: Patients and HC differed significantly on BMI (p < .002), EDE-Q total score (p < .000) and OCI-R total score (p < .000). No differences could be detected in grey matter (GM) regional volume between groups.

DISCUSSION: The ED-related cognitions in atypical AN patients would suggest that atypical AN and AN could be part of the same spectrum of restrictive-ED. However, contrary to previous reports in AN, our atypical AN patients did not show any GM volume reduction. The different degree of weight loss might play a role in determining such discrepancy. Alternatively, the preservation of GM volume might indeed differentiate atypical AN from AN.

Keywords
MRI, OSFED, VBM, adolescent, anorexia, eating disorders, imaging
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-336179 (URN)10.1002/eat.22805 (DOI)000418270800005 ()29215777 (PubMedID)
Funder
Swedish Research Council FormasSwedish Research CouncilThe Swedish Brain Foundation
Available from: 2017-12-12 Created: 2017-12-12 Last updated: 2018-02-19Bibliographically approved
Haller, S., Vernooij, M. W., Kuijer, J. P., Larsson, E.-M., Jäger, H. R. & Barkhof, F. (2018). Cerebral Microbleeds: Imaging and Clinical Significance. Radiology, 287(1), 11-28
Open this publication in new window or tab >>Cerebral Microbleeds: Imaging and Clinical Significance
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2018 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 287, no 1, p. 11-28Article in journal (Refereed) Published
Abstract [en]

Cerebral microbleeds (CMBs), also referred to as cerebral microhemorrhages, are small hypointense foci with a maximum size up to 5 mm or even 10 mm detected by using susceptibility-weighted (SW) magnetic resonance (MR) imaging (1–5). Histopathologically, CMBs represent focal accumulations of hemosiderin-containing macrophages (6) with paramagnetic properties causing signal loss because of susceptibility effects. Because of the increasing use of high-field-strength MR imaging systems and dedicated imaging sequences—notably, three-dimensional T2*-weighted imaging, SW imaging, and related techniques—CMBs are increasingly depicted during MR imaging of the brain. CMBs may be observed as an incidental finding or in the context of a specific pathologic finding such as cerebral amyloid angiopathy (CAA). Despite the increased detection rate, clear guidance for radiologists for the interpretation of CMBs are currently lacking and their clinical significance remains controversial.

The sensitivity of MR imaging to depict microbleeds depends on technical aspects, for example, field strength and pulse-sequence parameters. To allow correct depiction of CMBs, we first discuss the optimal MR imaging technique. Once a potential CMB is observed, correct classification requires knowledge about pathologic correlations and potential CMB “mimics,” which we address in the next section. Then, we review the interpretation of CMBs in various clinical situations and diseases, such as aging, dementia, radiation therapy, and traumatic brain injury. Finally, we discuss the clinical significance of CMBs in stroke and the clinical management of CMBs.

National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-346992 (URN)10.1148/radiol.2018170803 (DOI)000427992600003 ()29558307 (PubMedID)
Available from: 2018-03-23 Created: 2018-03-23 Last updated: 2018-04-12Bibliographically approved
Mårtensson, J., Lätt, J., Åhs, F., Fredriksson, M., Söderlund, H., Schiöth, H. B., . . . Nilsson, M. (2018). Diffusion tensor imaging and tractography of the white matter in normal aging: The rate-of-change differs between segments within tracts. Magnetic Resonance Imaging, 45, 113-119, Article ID S0730-725X(17)30059-0.
Open this publication in new window or tab >>Diffusion tensor imaging and tractography of the white matter in normal aging: The rate-of-change differs between segments within tracts
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2018 (English)In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 45, p. 113-119, article id S0730-725X(17)30059-0Article in journal (Refereed) Published
Abstract [en]

Knowledge concerning the normal aging of cerebral white matter will improve our understanding of abnormal changes in neurodegenerative diseases. The microstructural basis of white matter maturation and aging can be investigated using diffusion tensor imaging (DTI). Generally, diffusion anisotropy increases during childhood and adolescence followed by a decline in middle age. However, this process is subject to spatial variations between tracts. The aim of this study was to investigate to what extent age-related variations also occur within tracts. DTI parameters were compared between segments of two white matter tracts, the cingulate bundle (CB) and the inferior fronto-occipital fasciculus (IFO), in 257 healthy individuals between 13 and 84years of age. Segments of the CB and the IFO were extracted and parameters for each segment were averaged across the hemispheres. The data was analysed as a function of age. Results show that age-related changes differ both between and within individual tracts. Different age trajectories were observed in all segments of the analysed tracts for all DTI parameters. In conclusion, aging does not affect white matter tracts uniformly but is regionally specific; both between and within white matter tracts.

Keywords
Tractography, Inferior fronto-occipital fasciculus, Cingulum, Aging, White matter degeneration, White matter tract
National Category
Medical and Health Sciences Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-319599 (URN)10.1016/j.mri.2017.03.007 (DOI)000417772500015 ()28359912 (PubMedID)
Available from: 2017-04-06 Created: 2017-04-06 Last updated: 2018-02-19Bibliographically approved
Olivo, G., Latini, F., Wiemerslage, L., Larsson, E.-M. & Schiöth, H. B. (2018). Disruption of Accumbens and Thalamic White Matter Connectivity Revealed by Diffusion Tensor Tractography in Young Men with Genetic Risk for Obesity. Frontiers in Human Neuroscience, 12, Article ID 75.
Open this publication in new window or tab >>Disruption of Accumbens and Thalamic White Matter Connectivity Revealed by Diffusion Tensor Tractography in Young Men with Genetic Risk for Obesity
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2018 (English)In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 12, article id 75Article in journal (Refereed) Published
Abstract [en]

Background: Neurovascular coupling is associated with white matter (WM) structural integrity, and it is regulated by specific subtypes of dopaminergic receptors. An altered activity of such receptors, highly expressed in reward-related regions, has been reported in carriers of obesity-risk alleles of the fat mass and obesity associated (FTO) gene. Among the reward-related regions, the thalamus and the nucleus accumbens are particularly vulnerable to blood pressure dysregulation due to their peculiar anatomo-vascular characteristics, and have been consistently reported to be altered in early-stage obesity. We have thus hypothesized that a disruption in thalamus and nucleus accumbens WM microstructure, possibly on neurovascular basis, could potentially be a predisposing factor underlying the enhanced risk for obesity in the risk-allele carriers.

Methods: We have tested WM integrity in 21 male participants genotyped on the FTO risk single nucleotide polymorphisms (SNP) rs9939609, through a deterministic tractography analysis. Only homozygous participants (9 AA, 12 TT) were included. 11 tracts were selected and categorized as following according to our hypothesis: “risk tracts”, “obesity-associated tracts”, and a control tract (forcpes major). We investigated whether an association existed between genotype, body mass index (BMI) and WM microstructural integrity in the “risk-tracts” (anterior thalamic radiation and accumbofrontal fasciculus) compared to other tracts. Moreover, we explored whether WM diffusivity could be related to specific personality traits in terms of punishment and reward sensitivity, as measure by the BIS/BAS questionnaire.

Results: An effect of the genotype and an interaction effect of genotype and BMI were detected on the fractional anisotropy (FA) of the “risk tracts”. Correlations between WM diffusivity parameters and measures of punishment and reward sensitivity were also detected in many WM tracts of both networks.

Conclusions: A disruption of the structural connectivity from the nucleus accumbens and the thalamus might occur early in carriers of the FTO AA risk-allele, and possibly act as a predisposing factor to the development of obesity.

Keywords
DTI, FTO, MRI, accumbens, obesity, thalamus, tractography, white matter
National Category
Neurosciences
Identifiers
urn:nbn:se:uu:diva-346993 (URN)10.3389/fnhum.2018.00075 (DOI)000425773500001 ()29520227 (PubMedID)
Funder
Swedish Research CouncilThe Swedish Brain Foundation
Available from: 2018-03-23 Created: 2018-03-23 Last updated: 2018-04-12Bibliographically approved
Virhammar, J., Laurell, K., Cesarini, K. G. & Larsson, E.-M. (2018). Increase in callosal angle and decrease in ventricular volume after shunt surgery in patients with idiopathic normal pressure hydrocephalus.. Journal of Neurosurgery, 1-6
Open this publication in new window or tab >>Increase in callosal angle and decrease in ventricular volume after shunt surgery in patients with idiopathic normal pressure hydrocephalus.
2018 (English)In: Journal of Neurosurgery, ISSN 0022-3085, E-ISSN 1933-0693, p. 1-6Article in journal (Refereed) Epub ahead of print
Abstract [en]

OBJECTIVE Postoperative decrease in ventricle size is usually not detectable either by visual assessment or by measuring the Evans index in patients with idiopathic normal pressure hydrocephalus (iNPH). The aim of the present study was to investigate whether the angle between the lateral ventricles (the callosal angle [CA]) increases and ventricular volume decreases after shunt surgery in patients with iNPH. METHODS Magnetic resonance imaging of the brain was performed before and 3 months after shunt surgery in 18 patients with iNPH. The CA and Evans index were measured on T1-weighted 3D MR images, and ventricular volume contralateral to the shunt valve was measured with quantitative MRI. RESULTS The CA was larger postoperatively (mean 78°, 95% CI 69°-87°) than preoperatively (mean 67°, 95% CI 60°-73°; p < 0.001). The volume of the lateral ventricle contralateral to the shunt valve decreased from 73 ml (95% CI 66-80 ml) preoperatively to 63 ml (95% CI 54-72 ml) postoperatively (p < 0.001). The Evans index was 0.365 (95% CI 0.35-0.38) preoperatively and 0.358 (95% CI 0.34-0.38) postoperatively (p < 0.05). Postoperative change of CA showed a negative correlation with change of ventricular volume (r = -0.76, p < 0.01). CONCLUSIONS In this sample of patients with iNPH, the CA increased and ventricular volume decreased after shunt surgery. The relative difference was most pronounced for the CA, indicating that this accessible, noninvasive radiological marker should be evaluated further as an indirect method to determine shunt function in patients with iNPH.

Keywords
AC-PC = anterior commissure–posterior commissure, CA = callosal angle, Evans index, ICC = intraclass correlation coefficient, IQR = interquartile range, MMSE = Mini-Mental State Examination, NPH, QRAPMASTER = quantification of relaxation times and proton density by multiecho acquisition of saturation-recovery with turbo spin-echo readout, callosal angle, iNPH = idiopathic normal pressure hydrocephalus, normal pressure hydrocephalus, postoperative radiology, quantitative MRI, shunt dysfunction
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-342228 (URN)10.3171/2017.8.JNS17547 (DOI)29393749 (PubMedID)
Available from: 2018-02-19 Created: 2018-02-19 Last updated: 2018-03-14Bibliographically approved
Velickaite, V., Ferreira, D., Cavallin, L., Lind, L., Ahlström, H., Kilander, L., . . . Larsson, E.-M. (2018). Medial temporal lobe atrophy ratings in a large 75-year-old population-based cohort: gender-corrected and education-corrected normative data. European Radiology, 28(4), 1739-1747
Open this publication in new window or tab >>Medial temporal lobe atrophy ratings in a large 75-year-old population-based cohort: gender-corrected and education-corrected normative data
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2018 (English)In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 28, no 4, p. 1739-1747Article in journal (Refereed) Published
Abstract [en]

OBJECTIVES: To find cut-off values for different medial temporal lobe atrophy (MTA) measures (right, left, average, and highest), accounting for gender and education, investigate the association with cognitive performance, and to compare with decline of cognitive function over 5 years in a large population-based cohort.

METHODS: Three hundred and ninety 75-year-old individuals were examined with magnetic resonance imaging of the brain and cognitive testing. The Scheltens's scale was used to assess visually MTA scores (0-4) in all subjects. Cognitive tests were repeated in 278 of them after 5 years. Normal MTA cut-off values were calculated based on the 10th percentile.

RESULTS: Most 75-year-old individuals had MTA score ≤2. Men had significantly higher MTA scores than women. Scores for left and average MTA were significantly higher in highly educated individuals. Abnormal MTA was associated with worse results in cognitive test and individuals with abnormal right MTA had faster cognitive decline.

CONCLUSION: At age 75, gender and education are confounders for MTA grading. A score of ≥2 is abnormal for low-educated women and a score of ≥2.5 is abnormal for men and high-educated women. Subjects with abnormal right MTA, but normal MMSE scores had developed worse MMSE scores 5 years later.

KEY POINTS: • Gender and education are confounders for MTA grading. • We suggest cut-off values for 75-year-olds, taking gender and education into account. • Males have higher MTA scores than women. • Higher MTA scores are associated with worse cognitive performance.

Keywords
Cognitive test, Dementia, Longitudinal analysis, Medial temporal lobe atrophy (MTA), Population-based, Scheltens’s scale
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-333774 (URN)10.1007/s00330-017-5103-6 (DOI)000426645600044 ()29124383 (PubMedID)
Funder
Stockholm County CouncilThe Karolinska Institutet's Research Foundation
Available from: 2017-11-16 Created: 2017-11-16 Last updated: 2018-05-15Bibliographically approved
Georgiopoulos, C., Witt, S. T., Haller, S., Dizdar, N., Zachrisson, H., Engström, M. & Larsson, E.-M. (2018). Olfactory fMRI: implications of stimulation length and repetition time.. Chemical Senses
Open this publication in new window or tab >>Olfactory fMRI: implications of stimulation length and repetition time.
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2018 (English)In: Chemical Senses, ISSN 0379-864X, E-ISSN 1464-3553Article in journal (Refereed) Published
Abstract [en]

Studying olfaction with functional Magnetic Resonance imaging (fMRI) poses various methodological challenges. This study aimed to investigate the effects of stimulation length and repetition time (TR) on the activation pattern of four olfactory brain regions: the anterior and the posterior piriform cortex, the orbitofrontal cortex and the insula. 22 healthy participants with normal olfaction were examined with fMRI, with two stimulation lengths (6 seconds and 15 seconds) and two TRs (0.901 seconds and 1.34 seconds). Data were analyzed using General Linear Model (GLM), Tensorial Independent Component Analysis (TICA) and by plotting the event related time course of brain activation in the four olfactory regions of interest. The statistical analysis of the time courses revealed that short TR was associated with more pronounced signal increase and short stimulation was associated with shorter time to peak signal. Additionally, both long stimulation and short TR were associated with oscillatory time courses, whereas both short stimulation and short TR resulted in more typical time courses. GLM analysis showed that the combination of short stimulation and short TR could result in visually larger activation within these olfactory areas. TICA validated that the tested paradigm was spatially and temporally associated with a functionally connected network that included all four olfactory regions. In conclusion, the combination of short stimulation and short TR is associated with higher signal increase and shorter time to peak, making it more amenable to standard GLM-type analyses than long stimulation and long TR, and it should, thus, be preferable for olfactory fMRI.

National Category
Radiology, Nuclear Medicine and Medical Imaging Neurosciences
Identifiers
urn:nbn:se:uu:diva-350749 (URN)10.1093/chemse/bjy025 (DOI)29726890 (PubMedID)
Available from: 2018-05-15 Created: 2018-05-15 Last updated: 2018-05-30Bibliographically approved
Nordin, K., Persson, J., Stening, E., Herlitz, A., Larsson, E.-M. & Söderlund, H. (2018). Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory. Hippocampus, 28(2), 151-163
Open this publication in new window or tab >>Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory
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2018 (English)In: Hippocampus, ISSN 1050-9631, E-ISSN 1098-1063, Vol. 28, no 2, p. 151-163Article in journal (Refereed) Published
Abstract [en]

The hippocampus (HC) interacts with distributed brain regions to support memory and shows significant volume reductions in aging, but little is known about age effects on hippocampal whole-brain structural covariance. It is also unclear whether the anterior and posterior HC show similar or distinct patterns of whole-brain covariance and to what extent these are related to memory functions organized along the hippocampal longitudinal axis. Using the multivariate approach partial least squares, we assessed structural whole-brain covariance of the HC in addition to regional volume, in young, middle-aged and older adults (n = 221), and assessed associations with episodic and spatial memory. Based on findings of sex differences in both memory and brain aging, we further considered sex as a potential modulating factor of age effects. There were two main covariance patterns: one capturing common anterior and posterior covariance, and one differentiating the two regions by capturing anterior-specific covariance only. These patterns were differentially related to associative memory while unrelated to measures of single-item memory and spatial memory. Although patterns were qualitatively comparable across age groups, participants' expression of both patterns decreased with age, independently of sex. The results suggest that the organization of hippocampal structural whole-brain covariance remains stable across age, but that the integrity of these networks decreases as the brain undergoes age-related alterations.

Keywords
aging, episodic memory, longitudinal axis, sex, spatial memory
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-335505 (URN)10.1002/hipo.22817 (DOI)29171897 (PubMedID)
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2018-05-09Bibliographically approved
Kockum, K., Lilja-Lund, O., Larsson, E.-M., Rosell, M., Söderström, L., Virhammar, J. & Laurell, K. (2018). The idiopathic normal-pressure hydrocephalus Radscale: a radiological scale for structured evaluation. European Journal of Neurology, 25(3), 569-576
Open this publication in new window or tab >>The idiopathic normal-pressure hydrocephalus Radscale: a radiological scale for structured evaluation
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2018 (English)In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 25, no 3, p. 569-576Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Despite the important role of imaging in diagnosing idiopathic normal pressure hydrocephalus (iNPH), a structured overall assessment of radiological signs is still lacking. The purpose of this study was to construct a radiological scale, composed of morphological signs of iNPH, and compare it with clinical symptoms.

METHODS: In this prospective, population based study of iNPH, 168 individuals (93 females, 75 males), mean age 75 years (range 66-92 years), underwent a computed tomography (CT) of the brain and a neurological examination with assessment of clinical symptoms according to Hellström's iNPH scale. Two radiologists, blinded to clinical data, independently evaluated and measured eight radiological parameters i.e. Evans' index, callosal angle, size of temporal horns, narrow high convexity sulci, dilated Sylvian fissures, focally dilated sulci, periventricular hypodensities and bulging of the lateral ventricular roof.

RESULTS: In a linear regression model, all parameters except ventricular roof bulging were significantly associated with clinical iNPH symptoms. The seven remaining parameters were summarized into a total iNPH Radscale score ranging from 0 to 12. There was a significant correlation (r = 0.55, P < 0.001) between the total score of the iNPH Radscale and clinical symptoms. The interrater agreement for the included radiological parameters was high (ICC = 0.74-0.97).

CONCLUSION: The iNPH Radscale may become a valuable diagnostic screening tool, allowing a structured radiological assessment. A high iNPH Radscale score together with clinical symptoms, should raise suspicion of iNPH motivating further evaluation for shunt-surgery.

Keywords
Gait disorders, Hydrocephalus, Memory disorders, Tomography, computed, neurologic, normal pressure
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-337702 (URN)10.1111/ene.13555 (DOI)000425631500025 ()29281156 (PubMedID)
Available from: 2018-01-03 Created: 2018-01-03 Last updated: 2018-04-25Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-6308-1387

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