| 1. |
- Boito, Deneb, 1993-, et al.
(författare)
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MRI with generalized diffusion encoding reveals damaged white matter in patients previously hospitalized for COVID-19 and with persisting symptoms at follow-up
- 2023
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Ingår i: Brain Communications. - : Oxford University Press. - 2632-1297. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- There is mounting evidence of the long-term effects of COVID-19 on the central nervous system, with patients experiencing diverse symptoms, often suggesting brain involvement. Conventional brain MRI of these patients shows unspecific patterns, with no clear connection of the symptomatology to brain tissue abnormalities, whereas diffusion tensor studies and volumetric analyses detect measurable changes in the brain after COVID-19. Diffusion MRI exploits the random motion of water molecules to achieve unique sensitivity to structures at the microscopic level, and new sequences employing generalized diffusion encoding provide structural information which are sensitive to intravoxel features. In this observational study, a total of 32 persons were investigated: 16 patients previously hospitalized for COVID-19 with persisting symptoms of post-COVID condition (mean age 60 years: range 41–79, all male) at 7-month follow-up and 16 matched controls, not previously hospitalized for COVID-19, with no post-COVID symptoms (mean age 58 years, range 46–69, 11 males). Standard MRI and generalized diffusion encoding MRI were employed to examine the brain white matter of the subjects. To detect possible group differences, several tissue microstructure descriptors obtainable with the employed diffusion sequence, the fractional anisotropy, mean diffusivity, axial diffusivity, radial diffusivity, microscopic anisotropy, orientational coherence (Cc) and variance in compartment’s size (CMD) were analysed using the tract-based spatial statistics framework. The tract-based spatial statistics analysis showed widespread statistically significant differences (P < 0.05, corrected for multiple comparisons using the familywise error rate) in all the considered metrics in the white matter of the patients compared to the controls. Fractional anisotropy, microscopic anisotropy and Cc were lower in the patient group, while axial diffusivity, radial diffusivity, mean diffusivity and CMD were higher. Significant changes in fractional anisotropy, microscopic anisotropy and CMD affected approximately half of the analysed white matter voxels located across all brain lobes, while changes in Cc were mainly found in the occipital parts of the brain. Given the predominant alteration in microscopic anisotropy compared to Cc, the observed changes in diffusion anisotropy are mostly due to loss of local anisotropy, possibly connected to axonal damage, rather than white matter fibre coherence disruption. The increase in radial diffusivity is indicative of demyelination, while the changes in mean diffusivity and CMD are compatible with vasogenic oedema. In summary, these widespread alterations of white matter microstructure are indicative of vasogenic oedema, demyelination and axonal damage. These changes might be a contributing factor to the diversity of central nervous system symptoms that many patients experience after COVID-19.
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| 2. |
- Tapper, Sofie, 1989-, et al.
(författare)
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A pilot study of essential tremor: cerebellar GABA+/Glx ratio is correlated with tremor severity
- 2020
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Ingår i: Cerebellum & ataxias. - : BioMed Central. - 2053-8871. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Essential tremor is a common movement disorder with an unclear origin. Emerging evidence suggests the role of the cerebellum and the thalamus in tremor pathophysiology. We examined the two main neurotransmitters acting inhibitory (GABA+) and excitatory (Glx) respectively, in the thalamus and cerebellum, in patients diagnosed with severe essential tremor. Furthermore, we also investigated the relationship between determined neurotransmitter concentrations and tremor severity in the essential tremor patients.
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| 3. |
- Barazanji, Nawroz, et al.
(författare)
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Irritable bowel syndrome in women: Association between decreased insular subregion volumes and gastrointestinal symptoms
- 2022
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Ingår i: NeuroImage. - : Elsevier. - 2213-1582. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- Irritable bowel syndrome (IBS) is a chronic pain disorder characterized by disturbed interactions between the gut and the brain with depression as a common comorbidity. In both IBS and depression, structural brain alterations of the insular cortices, key structures for pain processing and interoception, have been demonstrated but the specificity of these findings remains unclear. We compared the gray matter volume (GMV) of insular cortex (IC) subregions in IBS women and healthy controls (HC) and examined relations to gastrointestinal (GI) symptoms and glutamate + glutamine (Glx) concentrations. We further analyzed GMV of IC subregions in women with major depression (MDD) compared to HC and addressed possible differences between depression, IBS, IBS with depression and HC.
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| 4. |
- Blystad, Ida, 1972-, et al.
(författare)
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Quantitative MRI using relaxometry in malignant gliomas detects contrast enhancement in peritumoral oedema
- 2020
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Malignant gliomas are primary brain tumours with an infiltrative growth pattern, often with contrast enhancement on magnetic resonance imaging (MRI). However, it is well known that tumour infiltration extends beyond the visible contrast enhancement. The aim of this study was to investigate if there is contrast enhancement not detected visually in the peritumoral oedema of malignant gliomas by using relaxometry with synthetic MRI. 25 patients who had brain tumours with a radiological appearance of malignant glioma were prospectively included. A quantitative MR-sequence measuring longitudinal relaxation (R-1), transverse relaxation (R-2) and proton density (PD), was added to the standard MRI protocol before surgery. Five patients were excluded, and in 20 patients, synthetic MR images were created from the quantitative scans. Manual regions of interest (ROIs) outlined the visibly contrast-enhancing border of the tumours and the peritumoral area. Contrast enhancement was quantified by subtraction of native images from post GD-images, creating an R-1-difference-map. The quantitative R-1-difference-maps showed significant contrast enhancement in the peritumoral area (0.047) compared to normal appearing white matter (0.032), p = 0.048. Relaxometry detects contrast enhancement in the peritumoral area of malignant gliomas. This could represent infiltrative tumour growth.
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| 5. |
- Borgström, Max, et al.
(författare)
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Retinal thinning and brain atrophy in early MS and CIS
- 2020
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Ingår i: Acta Neurologica Scandinavica. - : Wiley-Blackwell Publishing Inc.. - 0001-6314 .- 1600-0404. ; 142:5, s. 418-427
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Tidskriftsartikel (refereegranskat)abstract
- Background Optical coherence tomography (OCT) could be complementary to magnetic resonance imaging (MRI) of the brain in monitoring course of multiple sclerosis (MS) and clinically isolated syndrome (CIS). Thinning of neurons in ganglion cell-inner plexiform layer (GCIPL) measured by OCT is assumed to be associated with brain atrophy. Objectives To evaluate association of GCIPL with brain parameters detected by quantitative MRI (qMRI) and MR-spectroscopy (MRS) in early MS and CIS. Methods Seventeen newly diagnosed MS and 18 CIS patients were prospectively included. The patients were assessed at baseline as well as at 1 year follow-up by OCT, qMRI and MRS. Brain parenchymal and myelin volumes (BPV, MYV respectively) and the corresponding fractions (BPF, MYF) were measured with qMRI. Metabolites including myo-inositol (myo-Ins) were measured in the normal-appearing white matter (NAWM) using MRS. T-tests and ANOVA were used to analyze group differences, and linear regression models to evaluate association of GCIPL with BPV, MYV and myo-Ins after correlation analysis. Results Disease activity reflected by lesions on MRI and presence of CSF oligoclonal IgG bands were more prominent in MS compared to CIS. GCIPL, BPV, MYV, BPF and MYF were reduced, while concentration of myo-Ins was increased in MS compared to CIS. Follow-up showed consistency of thinner GCIPL in MS compared to CIS. GCIPL thinning correlated with reduced BPV and MYV (P < .05 for both), but with increased myo-Ins (P < .01). Conclusions Significant GCIPL thinning occurs in early MS and is associated with enhanced brain inflammation and atrophy.
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| 6. |
- Eleftheriou, Andreas, et al.
(författare)
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Indication of Thalamo-Cortical Circuit Dysfunction in Idiopathic Normal Pressure Hydrocephalus : A Tensor Imaging Study
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Idiopathic normal pressure hydrocephalus (iNPH) is a disorder with unclear pathophysiology. The diagnosis of iNPH is challenging due to its radiological similarity with other neurodegenerative diseases and ischemic subcortical white matter changes. By using Diffusion Tensor Imaging (DTI) we explored differences in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in iNPH patients (before and after a shunt surgery) and healthy individuals (HI) and we correlated the clinical results with DTI parameters. Thirteen consecutive iNPH-patients underwent a pre- and post-operative clinical work-up: 10m walk time (w10mt) steps (w10ms), TUG-time (TUGt) and steps (TUGs); for cognitive function MMSE. Nine HI were included. DTI was performed before and 3 months after surgery, HI underwent DTI once. DTI differences analyzed by manually placing 12 regions-of-interest. In patients motor and balance function improved significantly after surgery (p=0.01, p=0.025). Higher nearly significant FA values found in the patients vs HI pre-operatively in the thalamus (p=0.07) accompanied by an almost significant lower ADC (p=0.08). Significantly FA and ADC-values were found between patients and HI in FWM (p=0.02, p=0.001) and almost significant (p=0.057) pre- vs postoperatively. Postoperatively we found a trend towards the HIs FA values and a strong significant negative correlation between FA changes vs. gait results in the FWM (r=-0.7, p=0.008). Our study gives a clear indication of an ongoing pathological process in the periventricular white matter, especially in the thalamus and in the frontal white matter supporting the hypothesis of a shunt reversible thalamo-cortical circuit dysfunction in iNPH.
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| 7. |
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| 8. |
- Kihlberg, Johan, Medicine doktor, 1970-, et al.
(författare)
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Magnetic resonance imaging incidents are severely underreported : a finding in a multicentre interview survey
- 2022
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Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 32:1, s. 477-488
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The purpose of this study was to develop a procedure to investigate the occurrence, character and causes of magnetic resonance (MR) imaging incidents. Methods: A semi-structured questionnaire was developed containing details such as safety zones, examination complexity, staff MR knowledge, staff categories, and implementation of EU directive 2013/35. We focused on formally reported incidents that had occurred during 2014–2019, and unreported incidents during one year. Thirteen clinical MR units were visited, and the managing radiographer was interviewed. Open questions were analysed using conventionally adopted content analysis. Results: Thirty-seven written reports for 5 years and an additional 12 oral reports for 1 year were analysed. Only 38% of the incidents were reported formally. Some of these incidents were catastrophic. Negative correlations were observed between the number of annual incidents (per scanner) and staff MR knowledge (Spearman’s rho − 0.41, p < 0.05) as well as the number of MR physicists per scanner (− 0.48, p < 0.05). It was notable that only half of the sites had implemented the EU directive. Quotes like ‘Burns are to be expected in MR’ and not even knowing the name of the incident reporting system suggested an inadequate safety culture. Finally, there was a desire among staff for MR safety education. Conclusions: MR-related incidents were greatly underreported, and some incidents could have had catastrophic outcomes. There is a great desire among radiographers to enhance the safety culture, but to achieve this, much more accessible education is required, as well as focused involvement of the management of the operations. Key Points: • Only one in three magnetic resonance–related incidents were reported. • Several magnetic resonance incidents could have led to catastrophic consequences. • Much increased knowledge about magnetic resonance safety is needed by radiologists and radiographers.
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