| 1. |
- Wallin, Ewa, et al.
(author)
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Acute brain lesions on magnetic resonance imaging in relation to neurological outcome after cardiac arrest
- 2018
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In: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 62:5, s. 625-647
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Journal article (peer-reviewed)abstract
- 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.
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| 2. |
- Wallin, Ewa, et al.
(author)
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Relationship of acute brain lesions on MRI after cardiac arrest treated with hypothermia to neurological outcome 6 months later
- 2016
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In: Insights into Imaging 7:Suppl 1, 2016. - : Springer.
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Conference paper (peer-reviewed)abstract
- Relationship of acute brain lesions on MRI after cardiac arrest treated with hypothermia to neurological outcome 6 months later,Purpose: To document the acute MRI findings in the brain of post-cardiac arrest (CA) patients treated with therapeutic hypothermia and their relationship to patient outcome after 6 months.Methods and Materials: MRI was performed prospectively 3-13 days (median 4) after CA in 56 patients regardless of the level of consciousness in three hospitals. The images were interpreted visually by two neuroradiologists. Apparent diffusion coefficient (ADC) was measured in predetermined areas in cerebral white matter, deep grey matter, cerebellar grey and white matter and the brainstem. Outcome was assessed using the Cerebral Performance Categories Scale (CPC ) and dichotomized into good and poor outcome.Results: Acute hypoxic lesions on diffusion-weighted MRI (DWI) were more common in patients with poor outcome (p=0.006) and affected mostly grey matter, deep or cortical, with or without involvement of underlying white matter. Pure white matter lesions were very few. Lesions in the occipital and temporal lobes, deep white matter and cerebellum were most associated with poor outcome. Reductions in the ADC, particularly in the occipital lobes, were more common in patients with poor outcome. None of the patients with an ADC below 604-678 x10-6 mm2/s (variation depending on the equipment and technique) in any region survived to 6 months.Conclusion: Extensive acute lesions in cortical regions and deep grey matter in visual analysis and regions with an ADC under the level 600-680 x10-6 mm2/s are associated with poor outcome. Lesions are fewer and mainly situated in the frontal and parietal lobes in patients with good outcome.
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| 3. |
- Blystad, Ida, et al.
(author)
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Synthetic MRI of the brain in a clinical setting
- 2012
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In: Acta Radiologica. - : Sage Publications. - 0284-1851 .- 1600-0455. ; 53:10, s. 1158-1163
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Journal article (peer-reviewed)abstract
- BACKGROUND:Conventional magnetic resonance imaging (MRI) has relatively long scan times for routine examinations, and the signal intensity of the images is related to the specific MR scanner settings. Due to scanner imperfections and automatic optimizations, it is impossible to compare images in terms of absolute image intensity. Synthetic MRI, a method to generate conventional images based on MR quantification, potentially both decreases examination time and enables quantitative measurements.PURPOSE:To evaluate synthetic MRI of the brain in a clinical setting by assessment of the contrast, the contrast-to-noise ratio (CNR), and the diagnostic quality compared with conventional MR images.MATERIAL AND METHODS:Twenty-two patients had synthetic imaging added to their clinical MR examination. In each patient, 12 regions of interest were placed in the brain images to measure contrast and CNR. Furthermore, general image quality, probable diagnosis, and lesion conspicuity were investigated.RESULTS:Synthetic T1-weighted turbo spin echo and T2-weighted turbo spin echo images had higher contrast but also a higher level of noise, resulting in a similar CNR compared with conventional images. Synthetic T2-weighted FLAIR images had lower contrast and a higher level of noise, which led to a lower CNR. Synthetic images were generally assessed to be of inferior image quality, but agreed with the clinical diagnosis to the same extent as the conventional images. Lesion conspicuity was higher in the synthetic T1-weighted images, which also had a better agreement with the clinical diagnoses than the conventional T1-weighted images.CONCLUSION:Synthetic MR can potentially shorten the MR examination time. Even though the image quality is perceived to be inferior, synthetic images agreed with the clinical diagnosis to the same extent as the conventional images in this study.
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| 4. |
- Falk, Anna, et al.
(author)
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Discrimination between glioma grades II and III in suspected low-grade gliomas using dynamic contrast-enhanced and dynamic susceptibility contrast perfusion MR imaging : a histogram analysis approach
- 2014
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In: Neuroradiology. - : Springer Science and Business Media LLC. - 0028-3940 .- 1432-1920. ; 56:12, s. 1031-1038
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Journal article (peer-reviewed)abstract
- IntroductionPerfusion magnetic resonance imaging (MRI) can be used in the pre-operative assessment of brain tumours. The aim of this prospective study was to identify the perfusion parameters from dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) perfusion imaging that could best discriminate between grade II and III gliomas.MethodsMRI (3 T) including morphological ((T2 fluid attenuated inversion recovery (FLAIR) and T1-weighted (T1W)+Gd)) and perfusion (DCE and DSC) sequences was performed in 39 patients with newly diagnosed suspected low-grade glioma after written informed consent in this review board-approved study. Regions of interests (ROIs) in tumour area were delineated on FLAIR images co-registered to DCE and DSC, respectively, in 25 patients with histopathological grade II (n = 18) and III (n = 7) gliomas. Statistical analysis of differences between grade II and grade III gliomas in histogram perfusion parameters was performed, and the areas under the curves (AUC) from the ROC analyses were evaluated.ResultsIn DCE, the skewness of transfer constant (k trans) was found superior for differentiating grade II from grade III in all gliomas (AUC 0.76). In DSC, the standard deviation of relative cerebral blood flow (rCBF) was found superior for differentiating grade II from grade III gliomas (AUC 0.80).ConclusionsHistogram parameters from k trans (DCE) and rCBF (DSC) could most efficiently discriminate between grade II and grade III gliomas.
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| 5. |
- Holzgraefe, Bernhard, et al.
(author)
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Does permissive hypoxaemia during extracorporeal membrane oxygenation cause long-term neurological impairment? : A study in patients with H1N1-induced severe respiratory failure
- 2017
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In: European Journal of Anaesthesiology. - 0265-0215 .- 1365-2346. ; 34:2, s. 98-103
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Journal article (peer-reviewed)abstract
- BACKGROUND: The Extracorporeal Life Support Organisation accepts permissive hypoxaemia in adult patients during extracorporeal membrane oxygenation (ECMO). The neurological long-term outcome of this approach has not yet been studied.OBJECTIVES: We investigated the prevalence of brain lesions and cognitive dysfunction in survivors from the Influenza A/H1N1 2009 pandemic treated with permissive hypoxaemia during ECMO for severe acute respiratory distress syndrome (ARDS). Our hypothesis was that this method is reasonable if tissue hypoxia is avoided.DESIGN: Long-term follow-up study after ECMO.SETTING: Karolinska University Hospital, Sweden, from October 2012 to July 2013.PATIENTS: Seven patients treated with ECMO for severe influenza A/H1N1-induced ARDS were studied 3.2 years after treatment. Blood lactate concentrations were used as a surrogate for tissue oxygenation.INTERVENTIONS: Neurocognitive outcome was studied with standardised cognitive tests and MRI of the brain.MAIN OUTCOME MEASURES: Cognitive functioning and hypoxic brain lesions after permissive hypoxaemia during ECMO. The observation period was the first 10 days of ECMO or the entire treatment period if shorter than 10 days.RESULTS: Eleven of 13 patients were still alive 3 years after ECMO. We were able to contact seven of these patients (mean age 31 years), who all agreed to participate in this study. Mean +/- SD peripherally measured arterial saturation during the observation period was 79 +/- 10%. Full-scale Intelligence Quotient was within one standard deviation or above from the mean of a healthy population in five patients, and was 1.5 SD below the mean in one patient. In one other patient, it could not be determined because of a lack of formal education. Memory functioning was normal in all patients. MRI showed no changes related to cerebral hypoxia.CONCLUSIONS: Permissive hypoxaemia during ECMO might not negatively affect long-term cognitive outcome if adequate organ perfusion is maintained.
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| 6. |
- Laustsen, Søren Ravn, et al.
(author)
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Præoperativ funktionel magnetisk resonans-billeddannelse hos patienter med hjernetumor
- 2010
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In: Ugeskrift for læger. - 0041-5782 .- 1603-6824. ; 172:35, s. 2370-2376
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Functional Magnetic Resonance Imaging (fMRI) allows important functions in the brain cortex to be mapped noninvasively. The purpose with this work was to investigate a possible correlation between the distance from the tumour margin to fMRI activity and postoperative neurological deficits by means of a standardised method for measurement of distance. A second purpose was to investigate the influence of preoperative fMRI on the neurosurgical decision-making process. MATERIAL AND METHODS: Retrospective study of 25 patients. The inclusion criteria were surgery or biopsy after fMRI plus a three-month postoperative assessment. A total of 14 patients complied with these requirements (six men and eight women, the mean age was 39 years). fMRI raw data was collected using a three tesla magnetic resonance scanner (Signa HDx R14M5, GE Healthcare). The distance from the tumour margin to fMRI activation was measured using GE-reformat version 4.2 after raw data had been postprocessed using GE BrainwavePA version 1.3.08130. The neurosurgeons valuation of fMRI in the preoperative decision-making process was obtained using a standard questionnaire. RESULTS: There was a trend of association between distance from tumour to eloquent functional areas and the patients' postoperative neurological outcome (Fisher's exact test: distance < 15 mm, p = 0.43; distance < 10 mm, p = 0.14). fMRI proved very useful when deciding whether to operate or not (42%), when deciding the surgical approach (50%) and when deciding the extent of the surgical approach (83%). CONCLUSION: The standardised method for measurement of distance between tumour margin and fMRI activity can contribute to the preoperative risk assessment in patients with brain tumours.
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| 7. |
- Nordanskog, Pia, et al.
(author)
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Hippocampal volume in relation to clinical and cognitive outcome after electroconvulsive therapy in depression
- 2014
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In: Acta Psychiatrica Scandinavica. - United States : Wiley-Blackwell. - 0001-690X .- 1600-0447. ; 129:4, s. 303-311
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Journal article (peer-reviewed)abstract
- OBJECTIVE:In a previous magnetic resonance imaging (MRI) study, we found a significant increase in hippocampal volume immediately after electroconvulsive therapy (ECT) in patients with depression. The aim of this study was to evaluate hippocampal volume up to 1 year after ECT and investigate its possible relation to clinical and cognitive outcome.METHOD:Clinical and cognitive outcome in 12 in-patients with depression receiving antidepressive pharmacological treatment referred for ECT were investigated with the Montgomery-Asberg Depression Rating Scale (MADRS) and a broad neuropsychological test battery within 1 week before and after ECT. The assessments were repeated 6 and 12 months after baseline in 10 and seven of these patients, respectively. Hippocampal volumes were measured on all four occasions with 3 Tesla MRI.RESULTS:Hippocampal volume returned to baseline during the follow-up period of 6 months. Neither the significant antidepressant effect nor the significant transient decrease in executive and verbal episodic memory tests after ECT could be related to changes in hippocampal volume. No persistent cognitive side effects were observed 1 year after ECT.CONCLUSION:The immediate increase in hippocampal volume after ECT is reversible and is not related to clinical or cognitive outcome.
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| 8. |
- Nordanskog, Pia, et al.
(author)
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Increase in Hippocampal Volume After Electroconvulsive Therapy in Patients With Depression : A Volumetric Magnetic Resonance Imaging Study
- 2010
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In: JOURNAL OF ECT. - 1095-0680 .- 1533-4112. ; 26:1, s. 62-67
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Journal article (peer-reviewed)abstract
- Background: Major depression has traditionally been regarded as a neurochemical disease, but findings of a decreased hippocampal volume in patients with depression have turned the pathophysiological focus toward impairments in structural plasticity. The mechanisms of action of the most effective antidepressive treatment, electroconvulsive therapy (ECT), still remains elusive, but recent animal research has provided evidence for a cell proliferative effect in the hippocampus. The aim of this prospective study was to determine if hippocampal volume changes after ECT in patients with depression.Methods: Twelve patients with depression and ongoing antidepressive pharmacological treatment were investigated with clinical ratings and 3 T magnetic resonance imaging within 1 week before and after the ECT series. Each hippocampus was manually outlined on coronal slices, and the volume was calculated.Results: The left as well as the right hippocampal volume increased significantly after ECT.Conclusions: The hippocampal volume increases after ECT, supporting the hypothesis that hippocampus may play a central role in the treatment of depression.
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| 9. |
- Nylander, Ruta, et al.
(author)
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Relation between cardiovascular disease risk markers and brain infarcts detected by magnetic resonance imaging in an elderly population
- 2015
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In: Journal of Stroke & Cerebrovascular Diseases. - : Elsevier BV. - 1052-3057 .- 1532-8511. ; 24:2, s. 312-318
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Journal article (peer-reviewed)abstract
- BACKGROUND: Established cardiovascular risk markers, such as hypertension, are associated with increased risk of brain infarcts. The newer markers N-terminal pro-brain natriuretic peptide, troponin I, C-reactive protein, and cystatin C may affect the risk of cardiovascular events and potentially, thereby, also stroke. We investigated the association between established and new risk markers for cardiovascular disease and brain infarcts detected by magnetic resonance imaging (MRI) at age 75.METHODS: Four hundred six randomly selected subjects from the Prospective Investigation of the Vasculature in Uppsala Seniors study were examined with MRI of the brain at age 75. Blood samples, measurements, and dedicated questionnaires at age 70 were used for analysis of risk markers. A history of diseases had been obtained at age 70 and 75. MRI was evaluated regarding lacunar and cortical infarcts. Univariate associations between outcomes and risk markers were assessed with logistic regression models.RESULTS: One or more infarcts were seen in 23% of the subjects (20% had only lacunar infarcts, 1% had only cortical infarcts, and 2% had both). Hypertension (odds ratio [OR] 2.6, 95% confidence interval [CI] 1.4, 4.7) and obesity (OR 1.3; CI 1.0, 1.8) were significantly associated with increased risk of brain infarction. The newer risk markers were not significantly associated with the brain infarcts.CONCLUSIONS: The new markers were not associated with the predominantly lacunar infarcts in our 75-year-old population, why troponin I and NT-proBNP may be associated mainly with cardioembolic infarcts as shown recently.
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| 10. |
- Zetterling, Maria, et al.
(author)
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Extension of diffuse low-grade gliomas beyond radiological borders as shown by the coregistration of histopathological and magnetic resonance imaging data
- 2016
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In: Journal of Neurosurgery. - : AMER ASSOC NEUROLOGICAL SURGEONS. - 0022-3085 .- 1933-0693. ; 125:5, s. 1155-1166
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Journal article (peer-reviewed)abstract
- Background: Magnetic resonance imaging tends to underestimate the extent of diffuse low-grade gliomas (DLGGs). With the aim of studying the presence of tumor cells outside the radiological border, the authors developed a method of correlating MRI findings with histological data in patients with suspected DLGGs in whom en bloc resections were performed.Methods: Five patients with suspected DLGG suitable for en bloc resection were recruited from an ongoing prospective study. Sections of the entire tumor were immunostained with antibodies against mutated IDH1 protein (IDH1-R132H). Magnetic resonance images were coregistered with corresponding IDH1 images. The growth pattern of tumor cells in white and gray matter was assessed in comparison with signal changes on corresponding MRI slices.Results: Neuropathological assessment revealed DLGG in 4 patients and progression to WHO Grade III glioma in 1 patient. The tumor core consisted of a high density of IDH1-R132H–positive tumor cells and was located in both gray and white matter. Tumor cells infiltrated along the peripheral fibers of the white matter tracts. In all cases, tumor cells were found outside the radiological tumor border delineated on T2-FLAIR MRI sequences.Conclusions: The authors present a new method for the coregistration of histological and radiological characteristics of en bloc–removed infiltrative brain tumors that discloses tumor invasion at the radiological tumor borders. This technique can be applied to evaluate the sensitivity of alternative imaging methods to detect scattered tumor cells at tumor borders. Accurate methods for detection of infiltrative tumor cells will improve the possibility of performing radical tumor resection. In future studies, the method could also be used for in vivo studies of tumor invasion.
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