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1.
  • Nelander, Maria, et al. (författare)
  • Assessment of cerebral perfusion and edema in preeclampsia with intravoxel incoherent motion MRI
  • 2018
  • Ingår i: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 97:10, s. 1212-1218
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundCerebral complications are the main reasons for morbidity and mortality in preeclampsia and eclampsia. Still we do not know if the pathophysiology entails hypo- or hyperperfusion of the brain, or how and when edema emerges, due to the difficulty to examine the cerebral circulation.Material and methodsWe have used a non-invasive diffusion weighted magnetic resonance imaging (MRI) technique, intravoxel incoherent motion, to study cerebral perfusion on the capillary level and cerebral edema in women with preeclampsia (n=30), normal pregnancy (n=32) and non-pregnant women (n=16). Estimates of cerebral blood volume, blood flow and edema were measured in five different regions. These points were chosen to represent blood supply areas of both the carotid and vertebrobasilar arteries, and to include both white and grey matter.ResultsExcept for the caudate nucleus, we did not detect any differences in cerebral perfusion measures on a group level. In the caudate nucleus we found lower cerebral blood volume  and lower blood flow in preeclampsia compared to both normal pregnancy (p=0.01 and p=0.03, respectively) and non-pregnant women (both p=0.02). No differences in edema were detected between study groups.ConclusionThe cerebral perfusion measures were comparable between the study groups, except for a portion of the basal ganglia where hypoperfusion was detected in preeclampsia compared to normal pregnancy and non-pregnant women. 
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2.
  • Nelander, Maria, 1974-, et al. (författare)
  • Cerebral osmolytes and plasma osmolality in pregnancy and preeclampsia : a proton magnetic resonance spectroscopy study
  • 2018
  • Ingår i: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 31:7, s. 847-853
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Cerebral complications contribute substantially to mortality in preeclampsia. Pregnancy calls for extensive maternal adaptations, some associated with increased propensity for seizures, but the pathophysiology behind the eclamptic seizures is not fully understood. Plasma osmolality and sodium levels are lowered in pregnancy. This could result in extrusion of cerebral organic osmolytes, including the excitatory neurotransmitter glutamate, but this remains to be determined. The hypothesis of this study was that cerebral levels of organic osmolytes are decreased during pregnancy, and that this decrease is even more pronounced in women with preeclampsia.Method: We used proton magnetic resonance spectroscopy to compare levels of cerebral organic osmolytes, in women with preeclampsia (n=30), normal pregnancy (n=32) and non-pregnant controls (n=16). Cerebral levels organic osmolytes were further correlated to plasma osmolality, and plasma levels of glutamate and sodium.Results: Compared to non-pregnant women, women with normal pregnancy and preeclampsia had lower levels of the cerebral osmolytes myo-inositol, choline and creatine (p=0.001 or less), and all these metabolites correlated with each other (p<0.05). Women with normal pregnancies and preeclampsia had similar levels of osmolytes, except for glutamate, which was significantly lower in preeclampsia. Cerebral and plasma glutamate levels were negatively correlated with each other (p<0.008), and cerebral myo-inositol, choline and creatine levels were all positively correlated with both plasma osmolality and sodium levels (p<0.05).Conclusion: Our results indicate that pregnancy is associated with extrusion of cerebral organic osmolytes. This includes the excitatory neurotransmitter glutamate, which may be involved in the pathophysiology of seizures in preeclampsia.
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3.
  • Nelander, Maria, 1974- (författare)
  • Preeclampsia and the Brain : Epidemiological and Magnetic Resonance Studies
  • 2018
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Preeclampsia is a pregnancy specific syndrome that causes substantial maternal and fetal morbidity and mortality. One major contributor to maternal deaths is eclampsia, i.e. when seizures arise in the context of preeclampsia. The pathophysiology of eclampsia is still incompletely chartered and the long-term cerebral consequences of preeclampsia are also largely unknown.This thesis consists of a register based cohort study (n=3232, study I), and a cross-sectional neuroimaging study of pregnant women with and without preeclampsia (n=78, studies II-IV).In paper I, we compared the incidence of dementia and cardiovascular disease (CVD) between women ≥65 years with a self-reported history of hypertensive pregnancy, and women with a normotensive pregnancy. No difference was found regarding dementia, but an increased risk of CVD persisted among these elderly women.In paper II, we used phosphorus magnetic resonance spectroscopy to measure cerebral magnesium levels (Mg2+). We found lower levels of Mg2+ in women with preeclampsia than in women with normal pregnancy and non-pregnant women. Further, which was novel, we showed that lower cerebral Mg2+levels correlated with visual disturbances. The findings are interesting, since magnesium sulfate is the most effective treatment and prophylaxis for eclampsia, but with a largely unknown mechanism of action.In paper III, we measured cerebral organic osmolytes with proton magnetic resonance spectroscopy and found lower levels of osmolytes in pregnancy. Cerebral osmolytes were positively correlated with a decreased plasma osmolality, indicating that there is a joint biological mechanism. The only osmolyte that differed between women with preeclampsia and healthy pregnant women was glutamate. Glutamate is an excitatory neurotransmitter, which also functions as an osmolyte. Thus, lower cerebral glutamate levels could have implications on the pathophysiology of seizures.In paper IV, cerebral perfusion and edema were assessed with magnetic resonance imaging using intravoxel incoherent motion technique. A reduced perfusion fraction was found in a part of the basal ganglia in women with preeclampsia. No difference in edema was detected.Our findings indicate Mg2+ metabolism, plasma hypoosmolality and possibly cerebral hypoperfusion to be involved in the pathophysiology of cerebral affection in preeclampsia.
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4.
  • Bergman, Lina, et al. (författare)
  • Investigating Maternal Brain Alterations in Preeclampsia : the Need for a Multidisciplinary Effort
  • 2019
  • Ingår i: Current Hypertension Reports. - : Springer Science and Business Media LLC. - 1522-6417 .- 1534-3111. ; 21:9
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE OF REVIEW: To provide insight into the mechanisms underlying cerebral pathophysiology and to highlight possible methods for evaluation, screening, and surveillance of cerebral complications in preeclampsia.RECENT FINDINGS: The pathophysiology of eclampsia remains enigmatic. Animal studies show that the cerebral circulation in pregnancy and preeclampsia might be affected with increased permeability over the blood-brain barrier and altered cerebral blood flow due to impaired cerebral autoregulation. The increased blood pressure cannot be the only underlying cause of eclampsia and cerebral edema, since some cases of eclampsia arise without simultaneous hypertension. Findings from animal studies need to be confirmed in human tissues. Evaluation of brain alterations in preeclampsia and eclampsia is challenging and demands a multidisciplinary collaboration, since no single method can accurately and fully describe how preeclampsia affects the brain. Cerebral complications of preeclampsia are significant factors in maternal morbidity and mortality worldwide. No single method can accurately describe the full picture of how preeclampsia affects the brain vasculature and parenchyma. We recommend an international and multidisciplinary effort not only to overcome the issue of limited sample availability but also to optimize the quality of research.
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5.
  • Bergman, Lina, et al. (författare)
  • Preeclampsia and Increased Permeability Over the Blood–Brain Barrier : A Role of Vascular Endothelial Growth Receptor 2
  • 2021
  • Ingår i: American Journal of Hypertension. - : Oxford University Press. - 0895-7061 .- 1941-7225. ; 34:1, s. 73-81
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Cerebral complications in preeclampsia are leading causes of maternal mortality worldwide but the underlying pathophysiology is largely unknown and a challenge to study. Using an in vitro model of the human blood brain barrier (BBB), we explored the role of vascular endothelial growth factor receptor 2 (VEGFR2) in preeclampsia.METHODS: The human brain endothelial cell line (hCMEC/D3) cultured on Tranwells insert were exposed (12 h) to plasma from women with preeclampsia (n=28), normal pregnancy (n=28) and non-pregnant (n=16) controls. Transendothelial electrical resistance (TEER) and permeability to 70 kDa FITC-dextran were measured for assessment of BBB integrity. We explored possible underlying mechanisms, with focus on expression of tight junction proteins and phosphorylation of two tyrosine residues of VEGFR2, associated with vascular permeability and migration (pY951) and cell proliferation (pY1175). Plasma concentrations of soluble FMS like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured in order to establish correlations with in vitro results.RESULTS: hCMEC/D3 exposed to plasma from women with preeclampsia exhibited reduced TEER and increased permeability to 70 kDa FITC-dextran. Further, these cells up-regulated the mRNA levels of VEGFR2, as well as pY951-VEGFR2; but reduced pY1175-VEGFR2 (p&0.05 in all cases). No difference in mRNA expression of tight junction protein was observed between gruops. There was no correlation between angiogenic biomarkers and BBB permeability.CONCLUSION: We present a promising in vitro model of the BBB in preeclampsia. Selective tyrosine phosphorylation of VEGFR2 may participate in the increased BBB permeability in preeclampsia irrespective of plasma concentrations of angiogenic biomarkers.
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6.
  • Casar Borota, Olivera, et al. (författare)
  • Serotonin, ATRX, and DAXX Expression in Pituitary Adenomas : Markers in the Differential Diagnosis of Neuroendocrine Tumors of the Sellar Region.
  • 2017
  • Ingår i: American Journal of Surgical Pathology. - 0147-5185 .- 1532-0979. ; 41:9, s. 1238-1246
  • Tidskriftsartikel (refereegranskat)abstract
    • Differential diagnosis based on morphology and immunohistochemistry between a clinically nonfunctioning pituitary neuroendocrine tumor (NET)/pituitary adenoma and a primary or secondary NET of nonpituitary origin in the sellar region may be difficult. Serotonin, a frequently expressed marker in the NETs, has not been systematically evaluated in pituitary NETs. Although mutations in ATRX or DAXX have been reported in a significant proportion of pancreatic NETs, the mutational status of ATRX and DAXX and their possible pathogenetic role in pituitary NETs are unknown. Facing a difficult diagnostic case of an invasive serotonin and adrenocorticotroph hormone immunoreactive NET in the sellar region, we explored the immunohistochemical expression of serotonin, ATRX, and DAXX in a large series of pituitary endocrine tumors of different types from 246 patients and in 2 corticotroph carcinomas. None of the pituitary tumors expressed serotonin, suggesting that serotonin immunoreactive sellar tumors represent primary or secondary NETs of nonpituitary origin. Normal expression of ATRX and DAXX in pituitary tumors suggests that ATRX and DAXX do not play a role in the pathogenesis of pituitary endocrine tumors that remain localized to the sellar and perisellar region. A lack of ATRX or DAXX in a sellar NET suggests a nonpituitary NET, probably of pancreatic origin. One of the 2 examined corticotroph carcinomas, however, demonstrated negative ATRX immunolabeling due to an ATRX gene mutation. Further studies on a larger cohort of pituitary carcinomas are needed to clarify whether ATRX mutations may contribute to the metastatic potential in a subset of pituitary NETs.
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7.
  • Correia de Verdier, Maria, 1983-, et al. (författare)
  • Effect of MRI acquisition parameters on accuracy and precision of phase-contrast measurements in a small-lumen vessel phantom
  • 2024
  • Ingår i: European Radiology Experimental. - : Springer. - 2509-9280. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundPhase-contrast magnetic resonance imaging (PC-MRI) quantifies blood flow and velocity noninvasively. Challenges arise in neurovascular disorders due to small vessels. We evaluated the impact of voxel size, number of signal averages (NSA), and velocity encoding (VENC) on PC-MRI measurement accuracy and precision in a small-lumen vessel phantom.MethodsWe constructed an in vitro model with a constant flow rate using a 2.2-mm inner diameter plastic tube. A reservoir with a weight scale and timer was used as standard reference. Gradient-echo T1 weighted PC-MRI sequence was performed on a 3-T scanner with varying voxel size (2.5, 5.0, 7.5 mm3), NSA (1, 2, 3), and VENC (200, 300, 400 cm/s). We repeated measurements nine times per setting, calculating mean flow rate, maximum velocity, and least detectable difference (LDD).ResultsPC-MRI flow measurements were higher than standard reference values (mean ranging from 7.3 to 9.5 mL/s compared with 6.6 mL/s). Decreased voxel size improved accuracy, reducing flow rate measurements from 9.5 to 7.3 mL/s. The LDD for flow rate and velocity varied between 1 and 5%. The LDD for flow rate decreased with increased voxel size and NSA (p = 0.033 and 0.042). The LDD for velocity decreased with increased voxel size (p < 10-16). No change was observed when VENC varied.ConclusionsPC-MRI overestimated flow. However, it has high precision in a small-vessel phantom with constant flow rate. Improved accuracy was obtained with increasing spatial resolution (smaller voxels). Improved precision was obtained with increasing signal-to-noise ratio (larger voxels and/or higher NSA).Relevance statementPhase-contrast MRI is clinically used in large vessels. To further investigate the possibility of using phase-contrast MRI for smaller intracranial vessels in neurovascular disorders, we need to understand how acquisition parameters affect phase-contrast MRI-measured flow rate and velocity in small vessels.Key points• PC-MRI measures flow and velocity in a small lumen phantom with high precision but overestimates flow rate.• The precision of PC-MRI measurements matches the precision of standard reference for flow rate measurements.• Optimizing PC-MRI settings can enhance accuracy and precision in flow rate and velocity measurements.
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8.
  • Correia de Verdier, Maria, 1983- (författare)
  • Evaluation of Intracranial Arteriovenous Malformations with Magnetic Resonance Imaging
  • 2022
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Intracranial arteriovenous malformations (AVMs) are characterized by feeding arteries, a tangle of abnormal vessels (nidus) and draining veins. Radiological evaluation methods are used in diagnosing AVMs, treatment planning, post-treatment evaluation and monitoring stability. The general aim of our studies reviewed in this thesis was to develop and evaluate magnetic resonance imaging (MRI) techniques for the evaluation of AVMs. MethodsPaper I – In 30 patients treated with proton radiation therapy, radiation-induced MRI changes (vasogenic edema, contrast enhancement and cavitation) and their association with development of neurological symptoms and nidus obliteration were assessed. Paper II – We evaluated the effect of acquisition parameters (voxel size, number of signal averages and velocity encoding) on the accuracy and precision of phase-contrast MRI (PC-MRI)-measured flow and velocity in a small-lumen vessel phantom with constant flow. Paper III – Normal ranges and test-retest reproducibility of flow and velocity in the anterior, middle and posterior cerebral arteries were measured with PC-MRI in 30 healthy volunteers.Paper IV – We studied PC-MRI-measured flow and velocity in feeding arteries in 10 patients with AVMs and compared the values obtained with the results from paper III. We also assessed post-treatment changes in flow and velocity in three patients.  Results Paper I – Radiation-induced MRI changes were found in 87% of patients after proton radiation treatment of AVMs. MRI changes were associated with neurological symptoms but not with nidus obliteration. Paper II – PC-MRI overestimated flow in a small-lumen vessel phantom. Accuracy for flow measurements improved by decreasing voxel size. Precision for both flow and velocity measurements improved by increasing voxel size. Precision for flow measurements improved by increasing the number of signal averages.Paper III – We reported normal ranges and test-retest reproducibility for PC-MRI-measured flow and velocity in the main intracranial arteries. Reproducibility was overall quite low, but higher for the middle cerebral arteries than for the anterior and posterior cerebral arteries.Paper IV – Patients with a large nidus have increased velocity measured with PC-MRI in feeding arteries compared to intracranial arteries in healthy individuals. There is a reduction in PC-MRI-measured flow and velocity after treatment.  ConclusionRadiation-induced MRI changes are common after proton radiation treatment of AVMs. The accuracy and precision of PC-MRI measurements in a phantom depend on acquisition parameter settings. In patients with AVMs with a large nidus, increased velocity is observed in feeding arteries, and a decrease in flow and velocity is observed after treatment. PC-MRI can potentially be used as a clinical tool to aid treatment planning and post-treatment evaluation.  
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9.
  • Dubol, Manon, et al. (författare)
  • Acute nicotine exposure blocks aromatase in the limbic brain of healthy women : A [11C]cetrozole PET study
  • 2023
  • Ingår i: Comprehensive Psychiatry. - : Elsevier. - 0010-440X .- 1532-8384. ; 123
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Of interest to women's mental health, a wealth of studies suggests sex differences in nicotine addiction and treatment response, but their psychoneuroendocrine underpinnings remain largely unknown. A pathway involving sex steroids could indeed be involved in the behavioural effects of nicotine, as it was found to inhibit aromatase in vitro and in vivo in rodents and non-human primates, respectively. Aromatase regulates the synthesis of oestrogens and, of relevance to addiction, is highly expressed in the limbic brain.Methods: The present study sought to investigate in vivo aromatase availability in relation to exposure to nicotine in healthy women. Structural magnetic resonance imaging and two [11C]cetrozole positron emission tomography (PET) scans were performed to assess the availability of aromatase before and after administration of nicotine. Gonadal hormones and cotinine levels were measured. Given the region-specific expression of aromatase, a ROI -based approach was employed to assess changes in [11C]cetrozole non-displaceable binding potential.Results: The highest availability of aromatase was found in the right and left thalamus. Upon nicotine exposure, [11C]cetrozole binding in the thalamus was acutely decreased bilaterally (Cohen's d =-0.99). In line, cotinine levels were negatively associated with aromatase availability in the thalamus, although as non-significant trend.Conclusions: These findings indicate acute blocking of aromatase availability by nicotine in the thalamic area. This suggests a new putative mechanism mediating the effects of nicotine on human behaviour, particularly relevant to sex differences in nicotine addiction.
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10.
  • Dubol, Manon, et al. (författare)
  • Differential grey matter structure in women with premenstrual dysphoric disorder : evidence from brain morphometry and data-driven classification
  • 2022
  • Ingår i: Translational Psychiatry. - : Springer Nature. - 2158-3188. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Premenstrual dysphoric disorder (PMDD) is a female-specific condition classified in the Diagnostic and Statical Manual—5th edition under depressive disorders. Alterations in grey matter volume, cortical thickness and folding metrics have been associated with a number of mood disorders, though little is known regarding brain morphological alterations in PMDD. Here, women with PMDD and healthy controls underwent magnetic resonance imaging (MRI) during the luteal phase of the menstrual cycle. Differences in grey matter structure between the groups were investigated by use of voxel- and surface-based morphometry. Machine learning and multivariate pattern analysis were performed to test whether MRI data could distinguish women with PMDD from healthy controls. Compared to controls, women with PMDD had smaller grey matter volume in ventral posterior cortices and the cerebellum (Cohen’s d = 0.45–0.76). Region-of-interest analyses further indicated smaller volume in the right amygdala and putamen of women with PMDD (Cohen’s d = 0.34–0.55). Likewise, thinner cortex was observed in women with PMDD compared to controls, particularly in the left hemisphere (Cohen’s d = 0.20–0.74). Classification analyses showed that women with PMDD can be distinguished from controls based on grey matter morphology, with an accuracy up to 74%. In line with the hypothesis of an impaired top-down inhibitory circuit involving limbic structures in PMDD, the present findings point to PMDD-specific grey matter anatomy in regions of corticolimbic networks. Furthermore, the results include widespread cortical and cerebellar regions, suggesting the involvement of distinct networks in PMDD pathophysiology.
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11.
  • Dubol, Manon, et al. (författare)
  • Grey matter correlates of affective and somatic symptoms of premenstrual dysphoric disorder
  • 2022
  • Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 12:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Ovarian hormones fluctuations across the menstrual cycle are experienced by about 58% of women in their fertile age. Maladaptive brain sensitivity to these changes likely leads to the severe psychological, cognitive, and physical symptoms repeatedly experienced by women with Premenstrual Dysphoric Disorder (PMDD) during the late luteal phase of the menstrual cycle. However, the neuroanatomical correlates of these symptoms are unknown. The relationship between grey matter structure and PMDD symptom severity was delineated using structural magnetic resonance imaging during the late luteal phase of fifty-one women diagnosed with PMDD, combined with Voxel- and Surface-Based Morphometry, as well as subcortical volumetric analyses. A negative correlation was found between depression-related symptoms and grey matter volume of the bilateral amygdala. Moreover, the severity of affective and somatic PMDD symptoms correlated with cortical thickness, gyrification, sulcal depth, and complexity metrics, particularly in the prefrontal, cingulate, and parahippocampal gyri. The present findings provide the first evidence of grey matter morphological characteristics associated with PMDD symptomatology in brain regions expressing ovarian hormone receptors and of relevance to cognitive-affective functions, thus potentially having important implications for understanding how structural brain characteristics relate to PMDD symptomatology.
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12.
  • Engman, Jonas, et al. (författare)
  • Hormonal Cycle and Contraceptive Effects on Amygdala and Salience Resting-State Networks in Women with Previous Affective Side Effects on the Pill.
  • 2018
  • Ingår i: Neuropsychopharmacology. - : Springer Science and Business Media LLC. - 0893-133X .- 1740-634X. ; 43:3, s. 555-563
  • Tidskriftsartikel (refereegranskat)abstract
    • The mechanisms linking ovarian hormones to negative affect are poorly characterized, but important clues may come from the examination of the brain's intrinsic organization. Here, we studied the effects of both the menstrual cycle and oral contraceptives (OCs) on amygdala and salience network resting-state functional connectivity using a double-blind, randomized, and placebo-controlled design. Hormone levels, depressive symptoms, and resting-state functional connectivity were measured in 35 healthy women (24.9±4.2 years) who had previously experienced OC-related negative affect. All participants were examined in the follicular phase of a baseline cycle and in the third week of the subsequent cycle during treatment with either a combined OC (30 μg ethinyl estradiol/0.15 mg levonorgestrel) or placebo. The latter time point targeted the midluteal phase in placebo users and steady-state ethinyl estradiol and levonorgestrel concentrations in OC users. Amygdala and salience network connectivity generally increased with both higher endogenous and synthetic hormone levels, although amygdala-parietal cortical connectivity decreased in OC users. When in the luteal phase, the naturally cycling placebo users demonstrated higher connectivity in both networks compared with the women receiving OCs. Our results support a causal link between the exogenous administration of synthetic hormones and amygdala and salience network connectivity. Furthermore, they suggest a similar, potentially stronger, association between the natural hormonal variations across the menstrual cycle and intrinsic network connectivity.
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13.
  • Fahlström, Markus, et al. (författare)
  • A mathematical model for temporal cerebral blood flow response to acetazolamide evaluated in patients with Moyamoya disease
  • 2024
  • Ingår i: Magnetic Resonance Imaging. - : Elsevier. - 0730-725X .- 1873-5894. ; 110, s. 35-42
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Paired cerebral blood flow (CBF) measurement is usually acquired before and after vasoactive stimulus to estimate cerebrovascular reserve (CVR). However, CVR may be confounded because of variations in time-to-maximum CBF response (tmax) following acetazolamide injection. With a mathematical model, CVR can be calculated insensitive to variations in tmax, and a model offers the possibility to calculate additional model-derived parameters. A model that describes the temporal CBF response following a vasodilating acetazolamide injection is proposed and evaluated.Methods: A bi-exponential model was adopted and fitted to four CBF measurements acquired using arterial spin labelling before and initialised at 5, 15 and 25 min after acetazolamide injection in a total of fifteen patients with Moyamoya disease. Curve fitting was performed using a non-linear least squares method with a priori constraints based on simulations.Results: Goodness of fit (mean absolute error) varied between 0.30 and 0.62 ml·100 g-1·min-1. Model-derived CVR was significantly higher compared to static CVR measures. Maximum CBF increase occurred earlier in healthy- compared to diseased vascular regions.Conclusions: The proposed mathematical model offers the possibility to calculate CVR insensitive to variations in time to maximum CBF response which gives a more detailed characterisation of CVR compared to static CVR measures. Although the mathematical model adapts generally well to this dataset of patients with MMD it should be considered as experimental; hence, further studies in healthy populations and other patient cohorts are warranted.
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14.
  • Fahlström, Markus, et al. (författare)
  • Evaluation of Arterial Spin Labeling MRI : Comparison with 15O-Water PET on an Integrated PET/MR Scanner
  • 2021
  • Ingår i: Diagnostics (Basel). - : MDPI. - 2075-4418. ; 11:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Cerebral blood flow (CBF) measurements are of high clinical value and can be acquired non-invasively with no radiation exposure using pseudo-continuous arterial spin labeling (ASL). The aim of this study was to evaluate accordance in resting state CBF between ASL (CBFASL) and 15O-water positron emission tomography (PET) (CBFPET) acquired simultaneously on an integrated 3T PET/MR system. The data comprised ASL and dynamic 15O-water PET data with arterial blood sampling of eighteen subjects (eight patients with focal epilepsy and ten healthy controls, age 21 to 61 years). 15O-water PET parametric CBF images were generated using a basis function implementation of the single tissue compartment model. Cortical and subcortical regions were automatically segmented using Freesurfer. Average CBFASL and CBFPET in grey matter were 60 ± 20 and 75 ± 22 mL/100 g/min respectively, with a relatively high correlation (r = 0.78, p < 0.001). Bland-Altman analysis revealed poor agreement (bias = −15 mL/100 g/min, lower and upper limits of agreements = −16 and 45 mL/100 g/min, respectively) with a negative relationship. Accounting for the negative relationship, the width of the limits of agreement could be narrowed from 61 mL/100 g/min to 35 mL/100 g/min using regression-based limits of agreements. Although a high correlation between CBFASL and CBFPET was found, the agreement in absolute CBF values was not sufficient for ASL to be used interchangeably with 15O-water PET.
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15.
  • Fällmar, David, et al. (författare)
  • The extent of neuroradiological findings in COVID-19 shows correlation with blood biomarkers, Glasgow coma scale score and days in intensive care
  • 2022
  • Ingår i: Journal of neuroradiology. - : Elsevier. - 0150-9861 .- 1773-0406. ; 49:6, s. 421-427
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and purposeA wide range of neuroradiological findings has been reported in patients with coronavirus disease 2019 (COVID-19), ranging from subcortical white matter changes to infarcts, haemorrhages and focal contrast media enhancement. These have been descriptively but inconsistently reported and correlations with clinical findings and biomarkers have been difficult to extract from the literature. The purpose of this study was to quantify the extents of neuroradiological findings in a cohort of patients with COVID-19 and neurological symptoms, and to investigate correlations with clinical findings, duration of intensive care and biomarkers in blood.Material and methodsPatients with positive SARS-CoV-2 and at least one new-onset neurological symptom were included from April until July 2020. Nineteen patients were examined regarding clinical symptoms, biomarkers in blood and MRI of the brain. In order to quantify the MRI findings, a semi-quantitative neuroradiological severity scale was constructed a priori, and applied to the MR images by two specialists in neuroradiology.Results and conclusionsThe score from the severity scale correlated significantly with blood biomarkers of CNS injury (glial fibrillary acidic protein, total-tau, ubiquitin carboxyl-terminal hydrolase L1) and inflammation (C-reactive protein), Glasgow Coma Scale score, and the number of days spent in intensive care. The underlying radiological assessments had inter-rater agreements of 90.5%/86% (for assessments with 2/3 alternatives). Total intraclass correlation was 0.80.Previously reported neuroradiological findings in COVID-19 have been diverse and heterogenous. In this study, the extent of findings in MRI examination of the brain, quantified using a structured report, shows correlation with relevant biomarkers.
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16.
  • Gingnell, Malin, 1982-, et al. (författare)
  • Emotional anticipation after delivery - a longitudinal neuroimaging study of the postpartum period
  • 2017
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Neuroimaging research has begun to unveil the mechanisms behind emotion processing during the postpartum period, which, in turn, may be of relevance for the development of postpartum depression. The present study sought to longitudinally investigate the neural correlates of emotion anticipation during the postpartum period in healthy women. Functional magnetic resonance imaging was employed to measure the blood oxygen level-dependent signal in the brain in response to anticipation of negative emotional stimuli and during processing of images with positive or negative valence. The participating women were scanned twice: the first scan occurred during the first 48 hours after delivery, and the second was performed 4-6 weeks after delivery. The early postpartum period was characterized by higher anterior cingulate cortex reactivity during anticipation of negative emotional stimuli than the late postpartum period. This was accompanied by a negative relationship with insular reactivity during the early postpartum period and a trend towards an increase in insular reactivity in the late postpartum period. Thus, during the first four weeks of the postpartum period, a diminished top-down regulatory feedback on emotion-related areas of the brain was noted. This finding suggests a physiologically important adaptation during the healthy postpartum period.
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17.
  • Gu, Xuan, et al. (författare)
  • White matter microstructure and volume correlates of premenstrual dysphoric disorder
  • 2022
  • Ingår i: Journal of Psychiatry & Neuroscience. - : Canadian Medical Association. - 1180-4882 .- 1488-2434. ; 47:1, s. E67-E76
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Premenstrual dysphoric disorder (PMDD) is a mood disorder characterized by psychological and physical symptoms. Differences in white matter have been associated with affective and anxiety disorders, which share some symptoms with PMDD. However, whether white matter structure differs between the brains of individuals with PMDD and healthy controls is not known, nor is its relation to symptom severity.METHODS: We performed tract-based spatial statistics and voxel-based morphometry analyses of diffusion tensor imaging metrics and white matter volume, using 2 neuroimaging data sets (n = 67 and n = 131) and a combined whole-brain and region-of-interest approach. We performed correlation analyses to investigate the relationship between regions with different white matter microstructure and volume and PMDD symptom severity.RESULTS: We found greater fractional anisotropy in the left uncinate fasciculus (d = 0.69) in individuals with PMDD compared to controls. Moreover, the volume of the right uncinate fasciculus was higher in individuals with PMDD compared to controls (d = 0.40). As well, the severity of premenstrual depression was positively correlated with fractional anisotropy in the right superior longitudinal fasciculus (r = 0.35).LIMITATIONS: It is challenging to interpret group differences in diffusion tensor imaging metrics in terms of their underlying biophysical properties. The small size of the control group in the diffusion tensor imaging study may have prevented effects of interest from being detected.CONCLUSION: The findings of the present study provide evidence of differential cerebral white matter structure associated with PMDD and its symptoms.
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18.
  • Jonasson, My, et al. (författare)
  • Quantification of aromatase binding in the female human brain using [11 C]cetrozole positron emission tomography.
  • 2020
  • Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 98:11, s. 2208-2218
  • Tidskriftsartikel (refereegranskat)abstract
    • Aromatase, the enzyme that in the brain converts testosterone and androstenedione to estradiol and estrone, respectively, is a putative key factor in psychoneuroendocrinology. In vivo assessment of aromatase was performed to evaluate tracer kinetic models and optimal scan duration, for quantitative analysis of the aromatase positron emission tomography (PET) ligand [11 C]cetrozole. Anatomical magnetic resonance and 90-min dynamic [11 C]cetrozole PET-CT scans were performed on healthy women. Volume of interest (VOI)-based analyses with a plasma-input function were performed using the single-tissue and two-tissue (2TCM) reversible compartment models and plasma-input Logan analysis. Additionally, the simplified reference tissue model (SRTM), Logan reference tissue model (LRTM), and standardized uptake volume ratio model, with cerebellum as reference region, were evaluated. Parametric images were generated and regionally averaged voxel values were compared with VOI-based analyses of the reference tissue models. The optimal reference model was used for evaluation of a decreased scan duration. Differences between the plasma-input- and reference tissue-based methods and comparisons between scan durations were assessed by linear regression. The [11 C]cetrozole time-activity curves were best described by the 2TCM. SRTM nondisplaceable binding potential (BPND ), with cerebellum as reference region, can be used to estimate [11 C]cetrozole binding and generated robust and quantitatively accurate results for a reduced scan duration of 60 min. Receptor parametric mapping, a basis function implementation of SRTM, as well as LRTM, produced quantitatively accurate parametric images, showing BPND at the voxel level. As PET tracer, [11 C]cetrozole can be employed for relatively short brain scans to measure aromatase binding using a reference tissue-based approach.
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19.
  • Kaltsouni, Elisavet, et al. (författare)
  • Brain reactivity during aggressive response in women with premenstrual dysphoric disorder treated with a selective progesterone receptor modulator
  • 2021
  • Ingår i: Neuropsychopharmacology. - : Springer Nature. - 0893-133X .- 1740-634X. ; 46:8, s. 1460-1467
  • Tidskriftsartikel (refereegranskat)abstract
    • Premenstrual dysphoric disorder (PMDD) is a psychiatric condition characterized by late luteal phase affective, cognitive, and physical impairment. The disorder causes significant suffering in about 5% of women in their reproductive age. Altered sensitivity of cognitive-affective brain circuits to progesterone and its downstream metabolite allopregnanolone is suggested to underlie PMDD symptomatology. Core mood symptoms include irritability and anger, with aggression being the behavioral outcome of these symptoms. The present study sought to investigate the neural correlates of reactive aggression during the premenstrual phase in women with PMDD, randomized to a selective progesterone receptor modulator (SPRM) or placebo. Self-reports on the Daily Record of Severity of Problems were used to assess PMDD symptoms and gonadal hormone levels were measured by liquid chromatography tandem mass spectrometry. Functional magnetic resonance imaging was performed in 30 women with PMDD, while performing the point subtraction aggression paradigm. Overall, a high SPRM treatment response rate was attained (93%), in comparison with placebo (53.3%). Women with PMDD randomized to SPRM treatment had enhanced brain reactivity in the dorsal anterior cingulate cortex and dorsomedial prefrontal cortex during the aggressive response condition. The fronto-cingulate reactivity during aggressive responses depended on treatment, with a negative relationship between brain reactivity and task-related aggressiveness found in the placebo but not the SPRM group. The findings contribute to define the role of progesterone in PMDD symptomatology, suggesting a beneficial effect of progesterone receptor antagonism, and consequent anovulation, on top-down emotion regulation, i.e., greater fronto-cingulate activity in response to provocation stimuli.
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20.
  • Kaltsouni, Elisavet, et al. (författare)
  • Grey matter morphology in women with premenstrual dysphoric disorder treated with a selective progesterone receptor modulator.
  • 2022
  • Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 65, s. 35-43
  • Tidskriftsartikel (refereegranskat)abstract
    • Premenstrual dysphoric disorder (PMDD) is characterized by severe cyclic mood symptoms emerging in the luteal phase of the menstrual cycle. The variation in progesterone levels and its metabolites during the luteal phase seems critical to the occurrence of PMDD symptoms. Notably, the efficacy of selective progesterone receptor modulator (SPRM) treatment on the mental symptoms of PMDD has been recently demonstrated. In the present study, structural magnetic resonance imaging was used to assess the effects of SPRM treatment, compared with placebo, on grey matter morphology in women with PMDD. In total, 35 women were scanned during the luteal phase, before and after three months of treatment with SPRM or placebo. Symptom severity was assessed using the Daily Record of Severity of Problems (DRSP), while gonadal hormone levels were measured by liquid chromatography-tandem mass spectrometry. Region-of-interest and whole-brain approaches were employed to perform voxel-based morphometry analyses, subcortical volumetric analyses, and surface-based morphometry analyses. No interaction or main effects of treatment and time were observed on grey matter volume and cortical surface measures (cortical thickness, gyrification index, sulcal depth, and fractal dimension). The relationship between change in brain morphology and symptom severity was also explored but no treatment-dependant grey matter structure change was related to symptom severity change. These findings suggest that SPRM treatment does not impart macrostructural changes onto grey matter structure, at least in the short term.
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21.
  • Kaltsouni, Elisavet (författare)
  • Neuroimaging progesterone receptor modulation in patients with premenstrual dysphoric disorder : Is it just in your head?
  • 2024
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Premenstrual dysphoric disorder (PMDD) is a menstrually related mood disorder affecting about 5% of women during their reproductive years. The disorder is cyclic, with the symptomatology namely occurring at the luteal phase of a menstrual cycle, for most ovulatory menstrual cycles and entails a series of mood and physical symptoms. A neural susceptibility to regular hormonal fluctuations is hypothesized as the neuropathophysiological mechanism. While treatment options, such as selective serotonin reuptake inhibitors and hormonal interventions, are available, the neural mechanisms underlying symptom relief remain largely unclear. In this series of studies, a multimodal neuroimaging design was approach was used to reveal the neural correlates of three-month, low-dose selective progesterone receptor modulator (SPRM) treatment in comparison to a placebo. This treatment has been demonstrated to be effective in alleviating psychological symptoms associated with PMDD. Thirty-five women with fulfilling the criteria of a PMDD diagnosis were randomized to treatment with SPRM or placebo, with structural and functional MRI scans conducted before and after randomization. Findings indicated enhanced fronto-cingulate activity during a reactive aggression task in the SPRM treatment group compared to placebo, along with a negative association between aggressive responding and brain activity in the placebo group. Resting state functional connectivity was additionally altered after treatment with SPRM in fronto-visual, temporo-insular, and temporo-cerebellar regions. Additionally, a positive correlation was observed between the reduction in cortisol levels and the decrease in temporo-insular connectivity. No treatment effects were observed on brain structure, including grey and white matter volume, as well as cortical surface architecture. Lastly, White matter microstructure integrity did not differ longitudinally but showed cross-sectional differences. In conclusion, the effects of SPRM treatment were primarily observed in brain function, specifically in terms of enhanced cognitive control processing in the context of reactive aggression and resting state functional connectivity in regions relevant to cognitive and sensorimotor processing, with no significant structural alterations noted. Taken together, these findings confirm that the fluctuations rather than absolute levels of ovarian hormones are primary contributing to premenstrual symptomatology, potentially through hormonal-state dependent functional correlates. 
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22.
  • Kaltsouni, Elisavet, et al. (författare)
  • Selective progesterone receptor modulation and brain activity at rest in patients with premenstrual dysphoric disorder
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Ovarian hormones have been indicated to impact brain connectivity and mood. However, there is no consistent evidence on hormone-dependent functional connectivity and mental health. Alterations in resting state networks have been suggested as markers of affective disorders, but only preliminary evidence is provided on premenstrual dysphoric disorder, in which symptoms occur upon fluctuations of ovarian hormones. Recently, three-month low-dose selective progesterone receptor modulator (SPRM) administration has been associated with symptom relief and altered task-based brain reactivity during a reactive aggression condition. The present study sought to investigate the effect of this treatment on resting state functional connectivity (rs-FC) in patients with PMDD. Seed-based analyses were conducted, including including seeds from the classic resting state networks along with the functional cluster affected by SPRM treatment. Within previously identified networks related with emotional processing, rs-FC was compared between individuals with PMDD during the symptomatic luteal phase before randomization to treatment or placebo and during the end of the last treatment cycle. Seed-based rs-FC analyses yielded significant treatment by time effects on rs-FC between the left posterior superior temporal gyrus and the right insula cortex, between the posterior cerebellum and the left temporal pole, and between the right lateral visual network and left superior frontal gyrus. Visuo-frontal luteal phase connectivity decreased for the SPRM group and was positively correlated with changes in mood symptom severity in the placebo group. Cerebellar and temporal connectivity increased for the SPRM treatment group, while temporo-insular connectivity decreased and was positively correlated with cortisol levels. These findings indicate that SPRM treatment influenced rs-FC, which could be a relevant mechanism behind symptom alleviation.
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23.
  • Kaltsouni, Elisavet, et al. (författare)
  • White matter integrity upon progesterone antagonism in individuals with premenstrual dysphoric disorder: a randomized placebo-controlled diffusion tensor imaging study
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Premenstrual dysphoric disorder (PMDD) is a depressive disorder triggered by fluctuations of progesterone and estradiol during the luteal phase of the menstrual cycle. Selective progesterone receptor modulation (SPRM), while exerting an antagonistic effect on progesterone and maintaining the estradiol on moderate levels, has shown beneficial effects on the mental symptoms of PMDD. Progesterone is also known for its neuroprotective effects, while synthetic progestins have been suggested to promote myelination. However, the impact of this treatment on white matter neuroanatomy is unexplored. Diffusion tensor imaging was used to collect data on white matter integrity in patients with PMDD, before and after treatment with ulipristal acetate (an SPRM) or placebo, as part of a double-blind randomized controlled-trial. Tract based spatial statistics were performed to investigate SPRM treatment vs. placebo longitudinal effects on fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) on the whole white matter skeleton. Voxel-wise analyses indicated no change over time in any white matter microstructure metrics in individuals treated with SPRM versus placebo. Improvement in PMDD symptoms did not correlate with changes in white matter microstructure. In secondary, cross-sectional comparisons during treatment, the SPRM group displayed lower FA and higher MD, RD, and AD in several tracts. The main findings suggest that SPRM treatment did not impact white matter microstructure. However, the between-group differences after treatment call for further investigation on the tracts potentially impacted by progesterone antagonism.  
  •  
24.
  • Kaltsouni, Elisavet, et al. (författare)
  • White matter volume and treatment with selective progesterone receptor modulator in patients with premenstrual dysphoric disorder
  • 2024
  • Ingår i: Psychoneuroendocrinology. - : Elsevier. - 0306-4530 .- 1873-3360. ; 163
  • Tidskriftsartikel (refereegranskat)abstract
    • Premenstrual dysphoric disorder (PMDD) is a mood disorder for which selective progesterone receptor modulator (SPRM) treatment has been demonstrated to be beneficial. The neural signatures of this treatment have been so far identified as greater fronto-cingulate reactivity during aggressive response to provocation, but no changes in terms of gray matter structure. White matter has recently been found to differ between patients with PMDD and healthy controls. The present study thus sought to investigate the relationship between white matter volume and SPRM treatment in patients with PMDD. A pharmaco-neuroimaging study was conducted on patients with PMDD participating in a randomized controlled trial. Participants underwent magnetic resonance imaging before and after treatment randomization to ulipristal acetate (an SPRM), or placebo, for three months. The interaction effect of treatment by time on white matter volume (WMV) was assessed. Voxel based morphometry analyses were performed on both a whole brain exploratory level and on regions of interest. No treatment effect was observed on WMV in any region, including the anterior thalamic radiations, cingulum, forceps minor, fornix, inferior fronto-occipital fasciculus, superior cerebellar peduncle, superior longitudinal fasciculus, and uncinate fasciculus. This is the first finding to indicate that no white matter volume alterations follow three-month progesterone antagonism, suggesting that white matter volume does not participate in symptom relief upon SPRM treatment for PMDD.
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25.
  • Katsarogiannis, Evangelos, et al. (författare)
  • Absence of Oligoclonal Bands in Multiple Sclerosis : A Call for Differential Diagnosis
  • 2023
  • Ingår i: Journal of Clinical Medicine. - : MDPI AG. - 2077-0383. ; 12:14
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Immunoglobulin gamma (IgG) oligoclonal bands (OCB) in the cerebrospinal fluid (CSF) are absent in a small group of multiple sclerosis (MS) patients. According to previous research, OCB-negative MS patients differ genetically but not clinically from OCB-positive MS patients. However, whether OCB-negative MS is a unique immunological and clinical entity remains unclear. The absence of OCB poses a significant challenge in diagnosing MS. (1)Objective: The objective of this study was twofold: (1) to determine the prevalence of OCB-negative MS patients in the Uppsala region, and (2) to assess the frequency of misdiagnosis in this patient group. (2)Methods: We conducted a retrospective study using data from the Swedish MS registry (SMSreg) covering 83% of prevalent MS cases up to 20 June 2020 to identify all MS patients in the Uppsala region. Subsequently, we collected relevant information from the medical records of all OCB-negative MS cases, including age of onset, gender, presenting symptoms, MRI features, phenotype, Expanded Disability Status Scale (EDSS) scores, and disease-modifying therapies (DMTs). (3) Results: Out of 759 MS patients identified, 69 had an OCB-negative MS diagnosis. Upon re-evaluation, 46 patients had a typical history and MRI findings of MS, while 23 had unusual clinical and/or radiologic features. An alternative diagnosis was established for the latter group, confirming the incorrectness of the initial MS diagnosis. The average EDSS score was 2.0 points higher in the MS group than in the non-MS group (p = 0.001). The overall misdiagnosis rate in the cohort was 33%, with 22% of misdiagnosed patients having received DMTs. (4)Conclusions: Our results confirm that the absence of OCB in the CSF should raise suspicion of possible misdiagnosis in MS patients and prompt a diagnostic reassessment.
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26.
  • Nelander, Maria, et al. (författare)
  • Cerebral Magnesium Levels in Preeclampsia; A Phosphorus Magnetic Resonance Spectroscopy Study
  • 2017
  • Ingår i: American Journal of Hypertension. - : Oxford University Press (OUP). - 0895-7061 .- 1941-7225. ; 30:7, s. 667-672
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Magnesium sulfate (MgSO4) is used as a prophylaxis for eclamptic seizures. The exact mechanism of action is not fully established. We used phosphorus magnetic resonance spectroscopy (31P-MRS) to investigate if cerebral magnesium (Mg2+) levels differ between women with preeclampsia, normal pregnant, and nonpregnant women.METHODS: This cross-sectional study comprised 28 women with preeclampsia, 30 women with normal pregnancies in corresponding gestational week (range: 23-41 weeks) and 11 nonpregnant healthy controls. All women underwent 31P-MRS from the parieto-occipital region of the brain and were interviewed about cerebral symptoms. Differences between groups were assessed by analysis of variance and Tukey's post-hoc test. Correlations between Mg2+ levels and specific neurological symptoms were estimated with Spearman's rank test.RESULTS: Mean maternal cerebral Mg2+ levels were lower in women with preeclampsia (0.12 mM ± 0.02) compared to normal pregnant controls (0.14 mM ± 0.03) (P = 0.04). Nonpregnant and normal pregnant women did not differ in Mg2+ levels. Among women with preeclampsia, lower Mg2+ levels correlated with presence of visual disturbances (P = 0.04). Plasma levels of Mg2+ did not differ between preeclampsia and normal pregnancy.CONCLUSIONS: Women with preeclampsia have reduced cerebral Mg2+ levels, which could explain the potent antiseizure prophylactic properties of MgSO4. Within the preeclampsia group, women with visual disturbances have lower levels of Mg2+ than those without such symptoms.
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27.
  • Sohlberg, Sara, 1977-, et al. (författare)
  • MRI estimated placental perfusion in fetal growth assessment
  • 2015
  • Ingår i: Ultrasound in Obstetrics and Gynecology. - : Wiley. - 0960-7692 .- 1469-0705. ; 46:6, s. 700-705
  • Tidskriftsartikel (refereegranskat)abstract
    • ObjectiveThis study aimed to evaluate placental perfusion fraction estimated by magnetic resonance imaging (MRI) in vivo as a marker of placental function.MethodsThe study population included 35 pregnant women, of whom 13 had preeclampsia, examined at gestational weeks 22 to 40. Each woman underwent, within a 24 hour period: a MRI diffusion-weighted sequence (from which we calculated the placental perfusion fraction); venous blood sampling; and an ultrasound examination including estimation of fetal weight, amniotic fluid index and Doppler velocity measurements. We compared the perfusion fraction in pregnancies with and without fetal growth restriction and estimated correlations between the perfusion fraction and ultrasound estimates and plasma markers with linear regression. The associations between the placental perfusion fraction and ultrasound estimates were modified by the presence of preeclampsia (p < 0.05) and therefore we included an interaction term between preeclampsia and the covariates in the models.ResultsThe median placental perfusion fraction in pregnancies with and without fetal growth restriction was 21% and 32%, respectively (p = 0.005). The correlations between the placental perfusion fraction and ultrasound estimates and plasma markers were highly significant (p-values 0.002 to 0.0001). The highest coefficient of determination (R2= 0.56) for placental perfusion fraction was found for a model including pulsatility index in ductus venosus, plasma level of sFlt1, estimated fetal weight and presence of preeclampsia.ConclusionThe placental perfusion fraction has potential to contribute to the clinical assessment in cases of placental insufficiency.
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28.
  • Thorgeirsdottir, Lilja, et al. (författare)
  • Study protocol: establishment of a multicentre pre-eclampsia database and biobank in Sweden: GO PROVE and UP MOST, a prospective cohort study
  • 2021
  • Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 11:11
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Introduction Pre-eclampsia, a multisystem disorder in pregnancy, is one of the most common causes of maternal morbidity and mortality worldwide. However, we lack methods for objective assessment of organ function in pre-eclampsia and predictors of organ impairment during and after pre-eclampsia. The women’s and their partners’ experiences of pre-eclampsia have not been studied in detail. To phenotype different subtypes of the disorder is of importance for prediction, prevention, surveillance, treatment and follow-up of pre-eclampsia.The aim of this study is to set up a multicentre database and biobank for pre-eclampsia in order to contribute to a safer and more individualised treatment and care.Methods and analysis This is a multicentre cohort study. Prospectively recruited pregnant women ≥18 years, diagnosed with pre-eclampsia presenting at Sahlgrenska University Hospital, Uppsala University Hospital and at Södra Älvsborgs Hospital, Sweden, as well as normotensive controls are eligible for participation. At inclusion and at 1-year follow-up, the participants donate biosamples that are stored in a biobank and they are also asked to participate in various organ-specific evaluations. In addition, questionnaires and interviews regarding the women’s and partner’s experiences are distributed at follow-up.Ethics and dissemination By creating a database and biobank, we will provide the means to explore the disorder in a broader sense and allow clinical and laboratory discoveries that can be translated to clinical trials aiming at improved care of women with pre-eclampsia. Further, to evaluate experiences and the psychological impact of being affected by pre-eclampsia can improve the care of pregnant women and their partners. In case of incidental pathological findings during examinations performed, they will be handled in accordance with clinical routine. Data are stored in a secure online database. Biobank samples are identified through the women’s personal identification number and pseudonymised after identification in the biobank before analysis.This study was approved by the regional ethical review board in Gothenburg on 28 December 2018 (approval number 955-18) and by the Swedish Ethical Review Authority on 27 February 2019 (approval number 2019-00309).
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29.
  • Virhammar, Johan, et al. (författare)
  • Acute necrotizing encephalopathy with SARS-CoV-2 RNA confirmed in cerebrospinal fluid
  • 2020
  • Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 95:10, s. 445-449
  • Tidskriftsartikel (refereegranskat)abstract
    • Here, we report a case of COVID-19–related acute necrotizing encephalopathy where SARS-CoV-2 RNA was found in CSF 19 days after symptom onset after testing negative twice. Although monocytes and protein levels in CSF were only marginally increased, and our patient never experienced a hyperinflammatory state, her neurologic function deteriorated into coma. MRI of the brain showed pathologic signal symmetrically in central thalami, subinsular regions, medial temporal lobes, and brain stem. Extremely high concentrations of the neuronal injury markers neurofilament light and tau, as well as an astrocytic activation marker, glial fibrillary acidic protein, were measured in CSF. Neuronal rescue proteins and other pathways were elevated in the in-depth proteomics analysis. The patient received IV immunoglobulins and plasma exchange. Her neurologic status improved, and she was extubated 4 weeks after symptom onset. This case report highlights the neurotropism of SARS-CoV-2 in selected patients and emphasizes the importance of repeated lumbar punctures and CSF analyses in patients with suspected COVID-19 and neurologic symptoms.
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30.
  • Abdellah, Tebani, et al. (författare)
  • Annotation of pituitary neuroendocrine tumors with genome-wide expression analysis
  • 2021
  • Ingår i: Acta neuropathologica communications. - : BioMed Central (BMC). - 2051-5960. ; 9:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Pituitary neuroendocrine tumors (PitNETs) are common, generally benign tumors with complex clinical characteristics related to hormone hypersecretion and/or growing sellar tumor mass. PitNETs can be classified based on the expression pattern of anterior pituitary hormones and three main transcriptions factors (TF), SF1, PIT1 and TPIT that regulate differentiation of adenohypophysial cells. Here, we have extended this classification based on the global transcriptomics landscape using tumor tissue from a well-defined cohort comprising 51 PitNETs of different clinical and histological types. The molecular profiles were compared with current classification schemes based on immunohistochemistry. Our results identified three main clusters of PitNETs that were aligned with the main pituitary TFs expression patterns. Our analyses enabled further identification of specific genes and expression patterns, including both known and unknown genes, that could distinguish the three different classes of PitNETs. We conclude that the current classification of PitNETs based on the expression of SF1, PIT1 and TPIT reflects three distinct subtypes of PitNETs with different underlying biology and partly independent from the expression of corresponding hormones. The transcriptomic analysis reveals several potentially targetable tumor-driving genes with previously unknown role in pituitary tumorigenesis.
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31.
  • Abu Hamdeh, Sami, et al. (författare)
  • Intracranial pressure elevations in diffuse axonal injury : association with nonhemorrhagic MR lesions in central mesencephalic structures
  • 2019
  • Ingår i: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 131:2, s. 604-611
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: Increased intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI) with diffuse axonal injury (DAI) is not well defined. This study investigated the occurrence of increased ICP and whether clinical factors and lesion localization on MRI were associated with increased ICP in patients with DAI.Methods: Fifty-two patients with severe TBI (median age 24 years, range 9–61 years), who had undergone ICP monitoring and had DAI on MRI, as determined using T2*-weighted gradient echo, susceptibility-weighted imaging, and diffusion-weighted imaging (DWI) sequences, were enrolled. The proportion of good monitoring time (GMT) with ICP > 20 mm Hg during the first 120 hours postinjury was calculated and associations with clinical and MRI-related factors were evaluated using linear regression.Results: All patients had episodes of ICP > 20 mm Hg. The mean proportion of GMT with ICP > 20 mm Hg was 5%, and 27% of the patients (14/52) spent more than 5% of GMT with ICP > 20 mm Hg. The Glasgow Coma Scale motor score at admission (p = 0.04) and lesions on DWI sequences in the substantia nigra and mesencephalic tegmentum (SN-T, p = 0.001) were associated with the proportion of GMT with ICP > 20 mm Hg. In multivariable linear regression, lesions on DWI sequences in SN-T (8% of GMT with ICP > 20 mm Hg, 95% CI 3%–13%, p = 0.004) and young age (−0.2% of GMT with ICP > 20 mm Hg, 95% CI −0.07% to −0.3%, p = 0.002) were associated with increased ICP.Conclusions: Increased ICP occurs in approximately one-third of patients with severe TBI who have DAI. Age and lesions on DWI sequences in the central mesencephalon (i.e., SN-T) are associated with elevated ICP. These findings suggest that MR lesion localization may aid prediction of increased ICP in patients with DAI.Abbreviations: ADC = apparent diffusion coefficient; CPP = cerebral perfusion pressure; DAI = diffuse axonal injury; DWI = diffusion-weighted imaging; EVD = external ventricular drain; GCS = Glasgow Coma Scale; GMT = good monitoring time; GOSE = Glasgow Outcome Scale–Extended; ICC = intraclass correlation coefficient; ICP = intracranial pressure; MAP = mean arterial blood pressure; NICU = neurointensive care unit; SN-T = substantia nigra and mesencephalic tegmentum; SWI = susceptibility-weighted imaging; TBI = traumatic brain injury; T2*GRE = T2*-weighted gradient echo.
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32.
  • Abu Hamdeh, Sami, et al. (författare)
  • Intracranial pressure elevations in diffuse axonal injury are associated with non-hemorrhagic MR lesions in central mesencephalic structures
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Objective: Increased intracranial pressure (ICP) in severe traumatic brain injury (TBI) patients with diffuse axonal injury (DAI) is not well defined. This study investigated the occurrence of increased ICP and whether clinical factors and lesion localization on MRI were associated with increased ICP in DAI patients.Methods: Fifty-two severe TBI patients (median 24, range 9-61 years), with ICP-monitoring and DAI on MRI, using T2*-weighted gradient echo, susceptibility-weighted and diffusion-weighted (DW) sequences, were enrolled. Proportion of good monitoring time (GMT) with ICP>20 mmHg during the first 120 hours post-injury was calculated and associations with clinical and MRI-related factors were evaluated using linear regression. Results: All patients had episodes of ICP>20 mmHg. The mean proportion of GMT with ICP>20 mmHg was 5% and 27% of the patients (14/52) had more than 5% of GMT with ICP>20 mmHg. Glasgow Coma Scale motor score at admission (P=0.04) and lesions on DW images in the substantia nigra and mesencephalic tegmentum (SN-T, P=0.001) were associated with the proportion of GMT with ICP>20 mmHg. In multivariate linear regression, lesions on DW images in SN-T (8% of GMT with ICP>20 mmHg, 95% CI 3–13%, P=0.004) and young age (-0.2% of GMT with ICP>20 mmHg, 95% CI -0.07–-0.3%, P=0.0008) were associated with increased ICP.   Conclusions: Increased ICP occurs in ~1/3 of severe TBI patients with DAI. Age and lesions on DW images in the central mesencephalon (SN-T) associate with elevated ICP. These findings suggest that MR lesion localization may aid prediction of increased ICP in DAI patients.
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33.
  • Ali, Zafar, et al. (författare)
  • Homozygous GRID2 missense mutation predicts a shift in the D-serine binding domain of GluD2 in a case with generalized brain atrophy and unusual clinical features
  • 2017
  • Ingår i: BMC Medical Genetics. - : Springer Science and Business Media LLC. - 1471-2350. ; 18:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Spinocerebellar ataxias comprise a large and heterogeneous group of disorders that may present with isolated ataxia, or ataxia in combination with other neurologic or non-neurologic symptoms. Monoallelic or biallelic GRID2 mutations were recently reported in rare cases with cerebellar syndrome and variable degree of ataxia, ocular symptoms, hypotonia and developmental delay.CASE PRESENTATION: We report on a consanguineous family with autosomal recessive childhood onset of slowly progressive cerebellar ataxia and delayed psychomotor development in three siblings. MRI of an adult and affected family member revealed slightly widened cerebral and cerebellar sulci, suggesting generalized brain atrophy, and mild cerebellar atrophy. Using whole exome sequencing we identified a novel homozygous missense variant [c.2128C > T, p.(Arg710Trp)] in GRID2 that segregates with the disease. The missense variant is located in a conserved region encoding the extracellular serine-binding domain of the GluD2 protein and predicts a change in conformation of the protein.CONCLUSION: The widespread supratentorial brain abnormalities, absence of oculomotor symptoms, increased peripheral muscle tone and the novel missense mutation add to the clinical and genetic variability in GRID2 associated cerebellar syndrome. The neuroradiological findings in our family indicate a generalized neurodegenerative process to be taken into account in other families segregating complex clinical features and GRID2 mutations.
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34.
  • Almby, Kristina E., et al. (författare)
  • Effects of Gastric Bypass Surgery on the Brain : Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia
  • 2021
  • Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 70:6, s. 1265-1277
  • Tidskriftsartikel (refereegranskat)abstract
    • While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by F-18-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
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35.
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36.
  • Almqvist Téran, Nicolas, et al. (författare)
  • Posterior Fossa Volume and Dimensions : Relation to Pathophysiology and Surgical Outcomes in Classic Trigeminal Neuralgia
  • 2023
  • Ingår i: World Neurosurgery. - : Elsevier. - 1878-8750 .- 1878-8769. ; 179, s. e397-e403
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: A small posterior fossa (PF) has been hypothesized to explain the increased incidence of trigeminal neuralgia (TN) in females and could make microvascular decompression (MVD) more challenging. The aim of this study was to investigate the association between the PF volume and dimensions in relation to biological sex, type of neurovascular conflict (NVC), and outcome after MVD in classic TN.METHODS: In this observational study, 84 patients with TN operated on with MVD with a preoperative head computed tomography(CT) scan were included. Eighty-two adults without TN who had undergone head CT for other reasons were included as controls. PF volume and dimensions (x-axis, y-axis, and z-axis) were evaluated on the CT scans. For the patients with TN, Barrow Neurological Institute (BNI) grade was evaluated 6 months after MVD.RESULTS: There was no difference in PF volume or dimensions between the patients with TN and controls. Women showed a smaller volume and narrower (x-axis) PF than men, but these differences did not manifest when comparing patients with TN and controls within each sex. Patients with an NVC involving the superior cerebellar artery had a narrower (x-axis) and shorter (y-axis) PF than did patients with an NVC resulting from other arteries. PF volume or dimensions were not associated with BNI grade after MVD.CONCLUSIONS: PF anatomy was related to the NVC type but did not differ between patients with TN and controls and was not related to the surgical outcome after MVD.
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37.
  • Andersson, Jacob, et al. (författare)
  • Differences in head circumference and neuroimaging characteristics : what can they tell about the aetiologies of infant subdural haematoma?
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Background Acute (ASDH) and chronic subdural haematoma (CSDH) in infants have been regarded as highly specific for abuse. A recent study showed different risk factors for ASDH and CSDH, indicating that CSDH in many cases was related to external hydrocephalus. Purpose To investigate to what extent external hydrocephalus may explain findings and symptoms interpreted as signs of abusive head trauma. Material and methods Eighty-five infants with ASDH (n=16) and CSDH (n=69) were reviewed with regard to cranio-cortical- (CCW), sino-cortical- (SCW), frontal interhemispheric-(IHW), subarachnoid space width (SSW) and head circumference (HC). In infants with unilateral SDH, the correlation between the contralateral SSW and the ipsilateral CCW and SDH width was calculated. A correlation would imply that the CSDH replaces an already existing extracerebral space.Results Infants with CSDH had significantly higher CCW, SCW, IHW and SSW than infants with ASDH (p < 0.05). The ipsilateral CCW (R = 0.92, p < 0.001) and SDH width (R = 0.81, p < 0.01) were correlated to the contralateral SSW. Increased HC was more prevalent in Infants with CSDH (71%) than in infants with ASDH (14%) (p < 0.01). Forty-two infants, all with CSDH, had at least one of CCW, SCW or IHW ≥ 95th percentile. Twenty infants, all with CSDH, had CCW, SCW and IHW > 5 mm and increased HC. Conclusion A significant proportion of infants with CSDH may have external hydrocephalus as an underlying cause and that parts of the widened subarachnoid space in some infants is replaced by a CSDH.
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38.
  • Andersson, Jacob, et al. (författare)
  • Different vulnerability profiles in acute compared to chronic subdural haematoma amongst infants with suspected abusive head trauma
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Background: In a register study based on ICD 10 coding, there was a similar vulnerability profile (male sex, preterm and small for gestational age) in infants diagnosed with non-traumatic subdural haematoma (SDH) and infants having SDH with abuse diagnosis. However, ICD-10 does not separate between acute (ASDH) and chronic subdural haematoma (CSDH). Purpose: To determine the vulnerability profile in infants having CSDH and ASDH, respectively. Material and methods: A descriptive review of infants with SDH/hygroma examined by the Swedish National Board of Forensic Medicine between 1994 and 2018. Included cases (n=85) were analysed with regard to possible vulnerability factors. Results: Type of subdural fluid could be determined in 85 of 96 cases. Sixteen infants had ASDH and 69 CSDH. Infants with ASDH had the peak incidence during the first month of life, 56% were male, 6% were premature, 13% were twins and 44% died. In infants with CSDH, the peak incidence occurred during the third month of life, 69% were male, 34% were premature, 12% were twins and 4% died. Conclusion: CSDH, but not ASDH, is associated with factors suggesting non-traumatic pathogenesis, for which reason CSDH and ASDH should be analysed separately to extend the knowledge regarding the aetiology of SDH during infancy.   
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39.
  • Andersson, Jacob, et al. (författare)
  • External Hydrocephalus as a Cause of Infant Subdural Hematoma : Epidemiological and Radiological Investigations of Infants Suspected of Being Abused
  • 2022
  • Ingår i: Pediatric Neurology. - : Elsevier. - 0887-8994 .- 1873-5150. ; 126, s. 26-34
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Acute subdural hematoma (ASDH) and chronic subdural hematoma (CSDH) in infants have been regarded as highly specific for abuse. Other causes of CSDH have not been investigated in a large population.Purpose: The purpose of this study was to investigate to what extent external hydrocephalus is present in infants with ASDH and CSDH undergoing evaluation for abuse.Material and methods: Eighty-five infants suspected of being abused, with ASDH (n = 16) or CSDH (n = 69), were reviewed regarding age, risk factor profiles, craniocortical width (CCW), sinocortical width (SCW), frontal interhemispheric width (IHW), subarachnoid space width (SSW), and head circumference (HC). In infants with unilateral subdural hematoma (SDH), correlations between contralateral SSW and ipsilateral CCW and SDH width were investigated.Results: Infants with CSDH had significantly lower mortality, were more often premature and male, and had significantly higher CCW, SCW, IHW, and SSW than infants with ASDH (P < 0.05). Ipsilateral CCW (R = 0.92, P < 0.001) and SDH width (R = 0.81, P < 0.01) correlated with contralateral SSW. Increased HC was more prevalent in infants with CSDH (71%) than in infants with ASDH (14%) (P < 0.01). Forty-two infants, all with CSDH, had at least one of CCW, SCW, or IHW ≥95th percentile. Twenty infants, all with CSDH, had CCW, SCW, and IHW >5 mm, in addition to increased HC.Conclusion: A substantial proportion of infants with CSDH who had been suspected of being abused had findings suggesting external hydrocephalus.
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40.
  • Banerjee, Subhashis, et al. (författare)
  • Deep Curriculum Learning for Follow-up MRI Registration in Glioblastoma
  • 2023
  • Ingår i: Medical Imaging 2023. - : SPIE -Society of Photo-Optical Instrumentation Engineers. - 9781510660335 - 9781510660342
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents a weakly supervised deep convolutional neural network-based approach to perform voxel-level3D registration between subsequent follow-up MRI scans of the same patient. To handle the large deformation inthe surrounding brain tissues due to the tumor’s mass effect we proposed curriculum learning-based training forthe network. Weak supervision helps the network to concentrate more focus on the tumor region and resectioncavity through a saliency detection network. Qualitative and quantitative experimental results show the proposedregistration network outperformed two popular state-of-the-art methods.
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41.
  • Banerjee, Subhashis, et al. (författare)
  • Segmentation of Intracranial Aneurysm Remnant in MRA using Dual-Attention Atrous Net
  • 2021
  • Ingår i: 25th International Conference on Pattern Recognition (ICPR). - 9781728188089 ; , s. 9265-9272
  • Konferensbidrag (refereegranskat)abstract
    • Due to the advancement of non-invasive medical imaging modalities like Magnetic Resonance Angiography (MRA), an increasing number of Intracranial Aneurysm (IA) cases are being reported in recent years. The IAs are typically treated by so-called endovascular coiling, where blood flow in the IA is prevented by embolization with a platinum coil. Accurate quantification of the IA Remnant (IAR), i.e. the volume with blood flow present post treatment is the utmost important factor in choosing the right treatment planning. This is typically done by manually segmenting the aneurysm remnant from the MRA volume. Since manual segmentation of volumetric images is a labour-intensive and error-prone process, development of an automatic volumetric segmentation method is required. Segmentation of small structures such as IA, that may largely vary in size, shape, and location is considered extremely difficult. Similar intensity distribution of IAs and surrounding blood vessels makes it more challenging and susceptible to false positive. In this paper we propose a novel 3D CNN architecture called Dual-Attention Atrous Net (DAtt-ANet), which can efficiently segment IAR volumes from MRA images by reconciling features at different scales using the proposed Parallel Atrous Unit (PAU) along with the use of self-attention mechanism for extracting fine-grained features and intra-class correlation. The proposed DAtt-ANet model is trained and evaluated on a clinical MRA image dataset of IAR consisting of 46 subjects. We compared the proposed DAtt-ANet with five state-of-the-art CNN models based on their segmentation performance. The proposed DAtt-ANet outperformed all other methods and was able to achieve a five-fold cross-validation DICE score of 0.73 +/- 0.06.
  •  
42.
  • Banerjee, Subhashis, et al. (författare)
  • Streamlining neuroradiology workflow with AI for improved cerebrovascular structure monitoring
  • 2024
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 14:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Radiological imaging to examine intracranial blood vessels is critical for preoperative planning and postoperative follow-up. Automated segmentation of cerebrovascular anatomy from Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) can provide radiologists with a more detailed and precise view of these vessels. This paper introduces a domain generalized artificial intelligence (AI) solution for volumetric monitoring of cerebrovascular structures from multi-center MRAs. Our approach utilizes a multi-task deep convolutional neural network (CNN) with a topology-aware loss function to learn voxel-wise segmentation of the cerebrovascular tree. We use Decorrelation Loss to achieve domain regularization for the encoder network and auxiliary tasks to provide additional regularization and enable the encoder to learn higher-level intermediate representations for improved performance. We compare our method to six state-of-the-art 3D vessel segmentation methods using retrospective TOF-MRA datasets from multiple private and public data sources scanned at six hospitals, with and without vascular pathologies. The proposed model achieved the best scores in all the qualitative performance measures. Furthermore, we have developed an AI-assisted Graphical User Interface (GUI) based on our research to assist radiologists in their daily work and establish a more efficient work process that saves time.
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43.
  • Banerjee, Subhashis, et al. (författare)
  • Topology-Aware Learning for Volumetric Cerebrovascular Segmentation
  • 2022
  • Ingår i: 2022 IEEE International Symposium on Biomedical Imaging (IEEE ISBI 2022). - : IEEE. - 9781665429238 ; , s. 1-4
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents a topology-aware learning strategy for volumetric segmentation of intracranial cerebrovascular structures. We propose a multi-task deep CNN along with a topology-aware loss function for this purpose. Along with the main task (i.e. segmentation), we train the model to learn two related auxiliary tasks viz. learning the distance transform for the voxels on the surface of the vascular tree and learning the vessel centerline. This provides additional regularization and allows the encoder to learn higher-level intermediate representations to boost the performance of the main task. We compare the proposed method with six state-of-the-art deep learning-based 3D vessel segmentation methods, by using a public Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) dataset. Experimental results demonstrate that the proposed method has the best performance in this particular context.
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44.
  • Bannbers, Elin, 1984-, et al. (författare)
  • Prefrontal activity during response inhibition decreases over time in the postpartum period
  • 2013
  • Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 241, s. 132-138
  • Tidskriftsartikel (refereegranskat)abstract
    • The postpartum period is characterized by complex hormonal changes, but human imaging studies in the postpartum period have thus far predominantly focused on the neural correlates of maternal behavior or postpartum depression, whereas longitudinal studies on neural correlates of cognitive function across the postpartum period in healthy women are lacking. The aim of this study was to longitudinally examine response inhibition, as a measure of executive function, during the postpartum period and its neural correlates in healthy postpartum women and non-postpartum controls. Thirteen healthy postpartum women underwent event-related functional magnetic resonance imaging while performing a Go/NoGo task. The first assessment was made within 48 h of delivery, and the second at 4-7 weeks postpartum. In addition, 13 healthy women examined twice during the menstrual cycle were included as non-postpartum controls. In postpartum women region of interest analyses revealed task-related decreased activations in the right inferior frontal gyrus, right anterior cingulate, and bilateral precentral gyri at the late postpartum assessment. Generally, postpartum women displayed lower activity during response inhibition in the bilateral inferior frontal gyri and precentral gyri compared to non-postpartum controls. No differences in performance on the Go/NoGo task were found between time-points or between groups. In conclusion, this study has discovered that brain activity in prefrontal areas during a response inhibition task decreases throughout the course of the first postpartum weeks and is lower than in non-postpartum controls. Further studies on the normal adaptive brain activity changes that occur during the postpartum period are warranted. (C) 2012 Elsevier B.V. All rights reserved.
  •  
45.
  • Bergman, Lina, 1982, et al. (författare)
  • PROVE-Pre-Eclampsia Obstetric Adverse Events: Establishment of a Biobank and Database for Pre-Eclampsia
  • 2021
  • Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Pre-eclampsia is a leading cause of maternal and perinatal morbidity and mortality. The burden of disease lies mainly in low-middle income countries. The aim of this project is to establish a pre-eclampsia biobank in South Africa to facilitate research in the field of pre-eclampsia with a focus on phenotyping severe disease.The approach of our biobank is to collect biological specimens, detailed clinical data, tests, and biophysical examinations, including magnetic resonance imaging (MRI) of the brain, MRI of the heart, transcranial Doppler, echocardiography, and cognitive function tests.Women diagnosed with pre-eclampsia and normotensive controls are enrolled in the biobank at admission to Tygerberg University Hospital (Cape Town, South Africa). Biological samples and clinical data are collected at inclusion/delivery and during the hospital stay. Special investigations as per above are performed in a subset of women. After two months, women are followed up by telephonic interviews. This project aims to establish a biobank and database for severe organ complications of pre-eclampsia in a low-middle income country where the incidence of pre-eclampsia with organ complications is high. The study integrates different methods to investigate pre-eclampsia, focusing on improved understanding of pathophysiology, prediction of organ complications, and potentially future drug evaluation and discovery.
  •  
46.
  • Cederlund, Frida, et al. (författare)
  • Magnetic resonance imaging in the second trimester as a complement to ultrasound for diagnosis of fetal anomalies
  • 2024
  • Ingår i: Acta Radiologica Open. - : Sage Publications. - 2058-4601. ; 13:5
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundFetal ultrasound has limitations, especially if the patient is obese or in cases with oligohydramnios. Magnetic resonance imaging (MRI) can then be used as a complement, but only few studies have focused on examinations in the second trimester.PurposeTo validate MRI as a complement to diagnose fetal anomalies in the second trimester.Material and MethodsThis retrospective study retrieved data from January 2008 to July 2012 from the Fetal Medicine Unit and Department of Radiology at Uppsala University Hospital. Ultrasound and MRI findings were reviewed in 121 fetuses in relation to the final diagnosis, including postpartum follow-up and autopsy results.ResultsOf the 121 fetuses, 51 (42%) had a CNS anomaly and 70 (58%) a non-CNS anomaly diagnosed or suspected. MRI provided additional information in 21% of all cases without changing the management and revealed information that changed the management of the pregnancy in 13%. When a CNS anomaly was detected or suspected, the MRI provided additional information in 22% and changed the management in 10%. The corresponding figures for non-CNS cases were 21% and 16%, respectively. The proportion of cases with additional information that changed the management was especially high in patients with a BMI >30 kg/m2 (25%) and in patients with oligohydramnios (38%). In five cases in category III, false-positive ultrasound findings were identified.ConclusionsMRI in the second trimester complements ultrasound and improves diagnosis of fetal CNS- and non-CNS anomalies especially when oligohydramnios or maternal obesity is present.
  •  
47.
  • Christou, Constantina, et al. (författare)
  • Bifurcation of the intratemporal facial nerve : A rare anatomical anomaly
  • 2018
  • Ingår i: ACTA OTO-LARYNGOLOGICA CASE REPORTS. - : Taylor & Francis Group. - 2377-2484. ; 3:1, s. 15-18
  • Tidskriftsartikel (refereegranskat)abstract
    • The anatomical position of the facial nerve is a critical factor in determining surgical candidacy in patients with congenital aural atresia (CAA). All patients with CAA must preoperatively be evaluated using a grading score based on information gained from a high resolution CT scan. In patients not suitable for surgical reconstruction, implantation of novel hearing implants is increasingly used for hearing rehabilitation. We, here, describe a bifurcation of the intratemporal part of the facial nerve in a 5-year old boy with CAA undergoing implantation with a bone conductive hearing device.
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48.
  •  
49.
  • Correia de Verdier, Maria, 1983-, et al. (författare)
  • Hemodynamic evaluation of intracranial arteriovenous malformations : Pre- and post-treatment 2D phase-contrast MRI measurements
  • 2024
  • Ingår i: Acta Radiologica Open. - : Sage Publications. - 2058-4601. ; 13:8
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundHemodynamic changes are seen in the feeding arteries of arteriovenous malformations (AVMs). Phase-contrast MRI (PC-MRI) enables the acquisition of hemodynamic information from blood vessels. There is insufficient knowledge on which flow or velocity parameter best discriminates AVMs from healthy subjects.PurposeTo evaluate PC-MRI-measured flow and velocity in feeding arteries of AVMs before and, when possible, also after treatment and to compare these measurements to corresponding measurements in healthy controls.Materials and MethodsHighest flow (HF), lowest flow (LF), mean flow (MF), peak systolic velocity (PSV), end-diastolic velocity (EDV), and mean velocity (MV) were measured in feeding arteries in patients with intracranial AVMs using 2D PC-MRI at 3 T. Measurements were compared to previously reported values in healthy individuals. Values in patients above the 95th percentile in the healthy cohort were categorized as pathological. Nidus volume was measured using 3D time-of-flight MR angiography.ResultsTen patients with diagnosed AVMs were examined with PC-MRI. Among these, three patients also underwent follow-up PC-MRI after treatment. Pathological velocities (PSV, EDV, and MV) were seen in all five subjects with a nidus larger or equal to 5.7 cm3, whereas pathological flow values were not seen in all, that is, pathologic HF in three, pathologic LF in two, and pathologic MF in two. After treatment, there was a decrease in flow and velocity (all measured parameters). After treatment, velocities (PSV, EDV, and MV) were no longer abnormal compared to healthy controls.ConclusionPatients with a large AVM nidus show pathological velocities, but less consistent flow increases. Following treatment, velocities normalize.
  •  
50.
  • Correia de Verdier, Maria, et al. (författare)
  • Magnetic resonance imaging detected radiation-induced changes in patients with proton radiation-treated arteriovenous malformations
  • 2021
  • Ingår i: Acta Radiologica Open. - : Sage Publications. - 2058-4601. ; 10:10
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundTreatment of intracranial arteriovenous malformations (AVMs) includes surgery, radiation therapy, endovascular occlusion, or a combination. Proton radiation therapy enables very focused radiation, minimizing dose to the surrounding brain.PurposeTo evaluate the presence of radiation-induced changes on post-treatment MRI in patients with AVMs treated with proton radiation and to compare these with development of symptoms and nidus obliteration.Material and MethodsRetrospective review of pre- and post-treatment digital subtraction angiography and MRI and medical records in 30 patients with AVMs treated with proton radiation. Patients were treated with two or five fractions; total radiation dose was 20–35 physical Gy. Vasogenic edema (minimal, perinidal, or severe), contrast enhancement (minimal or annular), cavitation and nidus obliteration (total, partial, or none) were assessed.Results26 of 30 patients (87%) developed MRI changes. Vasogenic edema was seen in 25 of 30 (83%), abnormal contrast enhancement in 18 of 26 (69%) and cavitation in 5 of 30 (17%). Time from treatment to appearance of MRI changes varied between 5 and 25 months (median 7, mean 10). Seven patients developed new or deteriorating symptoms that required treatment with corticosteroids; all these patients had extensive MRI changes (severe vasogenic edema and annular contrast enhancement). Not all patients with extensive MRI changes developed symptoms. We found no relation between MRI changes and nidus obliteration.ConclusionRadiation-induced MRI changes are seen in a majority of patients after proton radiation treatment of AVMs. Extensive MRI changes are associated with new or deteriorating symptoms.
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