RESUMO
In multisite neuroimaging studies there is often unwanted technical variation across scanners and sites. These "scanner effects" can hinder detection of biological features of interest, produce inconsistent results, and lead to spurious associations. We propose mica (multisite image harmonization by cumulative distribution function alignment), a tool to harmonize images taken on different scanners by identifying and removing within-subject scanner effects. Our goals in the present study were to (1) establish a method that removes scanner effects by leveraging multiple scans collected on the same subject, and, building on this, (2) develop a technique to quantify scanner effects in large multisite studies so these can be reduced as a preprocessing step. We illustrate scanner effects in a brain MRI study in which the same subject was measured twice on seven scanners, and assess our method's performance in a second study in which ten subjects were scanned on two machines. We found that unharmonized images were highly variable across site and scanner type, and our method effectively removed this variability by aligning intensity distributions. We further studied the ability to predict image harmonization results for a scan taken on an existing subject at a new site using cross-validation.
Assuntos
Mapeamento Encefálico/métodos , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética , Algoritmos , Artefatos , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
BACKGROUND AND PURPOSE: Increasing evidence has demonstrated that aquaporin-4 (AQP4) immunoglobulin G causes damage to the kidney in neuromyelitis optica spectrum disorder (NMOSD). However, changes in urinalysis in NMOSD have not been investigated thus far. Our objective was to evaluate the changes in urinalysis in NMOSD patients. METHODS: Case data were collected from 44 patients with AQP4 antibody-positive NMOSD, 53 patients with multiple sclerosis (MS) and 79 age- and sex-matched healthy controls. Analyses of early morning urine and 24-h urine samples comparing NMOSD with MS patients were conducted. RESULTS: In the acute phase, urine pH levels (P < 0.001) and urine specific gravity levels (P < 0.001) from NMOSD patients were significantly higher and lower, respectively, than for MS patients. 24-h urine sodium and 24-h urine volume from NMOSD patients were significantly higher than for MS patients (both P = 0.001). A 24-h urine volume higher than 2500 ml (odds ratio 11.7, 95% confidence interval 1.863-73.066) and a 24-h urine sodium higher than 200 mmol (odds ratio 16.0, 95% confidence interval 2.122-120.648) are more likely to occur in NMOSD patients in the acute phase than in MS patients. CONCLUSIONS: The urinalysis results were significantly different between NMOSD patients and MS patients. The pathophysiological changes in AQP4 antibody-positive NMOSD patients were not limited to the central nervous system.
Assuntos
Neuromielite Óptica/urina , Urinálise , Adulto , Aquaporina 4/imunologia , Autoanticorpos , Feminino , Humanos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Neuromielite Óptica/imunologia , Estudos Prospectivos , Adulto JovemRESUMO
The high comorbidity among neuropsychiatric disorders suggests a possible common neurobiological phenotype. Resting-state regional cerebral blood flow (CBF) can be measured noninvasively with magnetic resonance imaging (MRI) and abnormalities in regional CBF are present in many neuropsychiatric disorders. Regional CBF may also provide a useful biological marker across different types of psychopathology. To investigate CBF changes common across psychiatric disorders, we capitalized upon a sample of 1042 youths (ages 11-23 years) who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. CBF at rest was quantified on a voxelwise basis using arterial spin labeled perfusion MRI at 3T. A dimensional measure of psychopathology was constructed using a bifactor model of item-level data from a psychiatric screening interview, which delineated four factors (fear, anxious-misery, psychosis and behavioral symptoms) plus a general factor: overall psychopathology. Overall psychopathology was associated with elevated perfusion in several regions including the right dorsal anterior cingulate cortex (ACC) and left rostral ACC. Furthermore, several clusters were associated with specific dimensions of psychopathology. Psychosis symptoms were related to reduced perfusion in the left frontal operculum and insula, whereas fear symptoms were associated with less perfusion in the right occipital/fusiform gyrus and left subgenual ACC. Follow-up functional connectivity analyses using resting-state functional MRI collected in the same participants revealed that overall psychopathology was associated with decreased connectivity between the dorsal ACC and bilateral caudate. Together, the results of this study demonstrate common and dissociable CBF abnormalities across neuropsychiatric disorders in youth.
Assuntos
Circulação Cerebrovascular/fisiologia , Transtornos Mentais/fisiopatologia , Psicopatologia/métodos , Adolescente , Biomarcadores/sangue , Encéfalo/patologia , Mapeamento Encefálico/métodos , Córtex Cerebral/fisiopatologia , Criança , Feminino , Giro do Cíngulo/diagnóstico por imagem , Giro do Cíngulo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Transtornos Mentais/diagnóstico por imagem , Transtornos Mentais/metabolismo , Philadelphia , Adulto JovemRESUMO
BACKGROUND: Peppermint oil (PO) has intrinsic properties that may benefit patients with irritable bowel syndrome (IBS) symptoms. The study objective was to determine the effect of peppermint oil in the treatment of the IBS. METHODS: We systematically searched MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (Cochrane CENTRAL), ClinicalTrials.gov, EMBASE (Ovid), and Web of Science for randomized controlled trials (RCTs) of PO for IBS. We appraised the eligible studies by the Cochrane risk of bias tool. We performed random-effects meta-analysis on primary outcomes including global improvement in IBS symptoms and abdominal pain. A PRISMA-compliant study protocol is registered in PROSPERO Register [2016, CRD42016050917]. RESULTS: Twelve randomized trials with 835 patients were included. For global symptom improvement, the risk ratio (RR) from seven RCTs for the effect of PO (n = 253) versus placebo (n = 254) on global symptoms was 2.39 [95% confidence interval (CI): 1.93, 2.97], I2 = 0%, z = 7.93 (p < 0.00001). Regarding abdominal pain, the RR from six RCTs for the effect of PO (n = 278) versus placebo (n = 278) was 1.78 [95% CI: 1.43, 2.20], I2 = 0%, z = 5.23 (p < 0.00001). Overall, there were no differences in the reported adverse effects: PO (32 events, 344 total, 9.3%) versus placebo (20 events, 327 total, 6.1%) for eight RCTs; RR 1.40 [95% CI: 0.87, 2.26] I2 = 0%, z = 1.39 (p = 0.16). The number needed to treat with PO to prevent one patient from having persistent symptoms was three for global symptoms and four for abdominal pain. CONCLUSIONS: In the most comprehensive meta-analysis to date, PO was shown to be a safe and effective therapy for pain and global symptoms in adults with IBS.
Assuntos
Síndrome do Intestino Irritável/tratamento farmacológico , Óleos de Plantas/uso terapêutico , Humanos , Mentha piperita , Resultado do TratamentoRESUMO
Depressive symptoms are common in multiple psychiatric disorders and are frequent sequelae of trauma. A dimensional conceptualization of depression suggests that symptoms should be associated with a continuum of deficits in specific neural circuits. However, most prior investigations of abnormalities in functional connectivity have typically focused on a single diagnostic category using hypothesis-driven seed-based analyses. Here, using a sample of 105 adult female participants from three diagnostic groups (healthy controls, n=17; major depression, n=38; and post-traumatic stress disorder, n=50), we examine the dimensional relationship between resting-state functional dysconnectivity and severity of depressive symptoms across diagnostic categories using a data-driven analysis (multivariate distance-based matrix regression). This connectome-wide analysis identified foci of dysconnectivity associated with depression severity in the bilateral amygdala. Follow-up seed analyses using subject-specific amygdala segmentations revealed that depression severity was associated with amygdalo-frontal hypo-connectivity in a network of regions including bilateral dorsolateral prefrontal cortex, anterior cingulate and anterior insula. In contrast, anxiety was associated with elevated connectivity between the amygdala and the ventromedial prefrontal cortex. Taken together, these results emphasize the centrality of the amygdala in the pathophysiology of depressive symptoms, and suggest that dissociable patterns of amygdalo-frontal dysconnectivity are a critical neurobiological feature across clinical diagnostic categories.
Assuntos
Conectoma/estatística & dados numéricos , Depressão/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adulto , Tonsila do Cerebelo/metabolismo , Tonsila do Cerebelo/fisiopatologia , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Transtornos de Ansiedade/fisiopatologia , Córtex Cerebral/fisiopatologia , Conectoma/métodos , Depressão/metabolismo , Transtorno Depressivo Maior/fisiopatologia , Feminino , Neuroimagem Funcional , Giro do Cíngulo/fisiopatologia , Humanos , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/metabolismoRESUMO
Adults with psychotic disorders have dysconnectivity in critical brain networks, including the default mode (DM) and the cingulo-opercular (CO) networks. However, it is unknown whether such deficits are present in youth with less severe symptoms. We conducted a multivariate connectome-wide association study examining dysconnectivity with resting state functional magnetic resonance imaging in a population-based cohort of 188 youths aged 8-22 years with psychosis-spectrum (PS) symptoms and 204 typically developing (TD) comparators. We found evidence for multi-focal dysconnectivity in PS youths, implicating the bilateral anterior cingulate, frontal pole, medial temporal lobe, opercular cortex and right orbitofrontal cortex. Follow-up seed-based and network-level analyses demonstrated that these results were driven by hyper-connectivity among DM regions and diminished connectivity among CO regions, as well as diminished coupling between frontal and DM regions. Collectively, these results provide novel evidence for functional dysconnectivity in PS youths, which show marked correspondence to abnormalities reported in adults with established psychotic disorders.
Assuntos
Conectoma , Transtornos Psicóticos/patologia , Adolescente , Mapeamento Encefálico , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Adulto JovemRESUMO
BACKGROUND AND PURPOSE: Our aim was to provide estimates of traumatic brain injury (TBI) in 2050 for the African population by region, sex and age strata. METHODS: A literature search was performed in October 2014 in PubMed for population-based studies of TBI in different geographical locations. Articles were selected from Kenya (model 1), New Zealand (model 2) and the USA (model 3). In model 1, rates of road traffic injury in Kenya were used to estimate TBI rates in the African continent. Models 2 and 3 used existing TBI incidence estimates from other locations to estimate the burden of TBI for Africa in 2050. The 2050 African population, as projected by the United Nations, was used as a base population. RESULTS: Based on rates from model 1, the estimated total TBI count in Africa in 2050 is 5.98 ± 0.03 million, with the highest count in eastern (2.04 ± 0.01 million) and lowest count in southern (0.15 ± 0.00 million) Africa. A higher TBI count is predicted by models 2 (14.25 ± 0.75 million) and 3 (10.40 ± 0.02 million). Estimated TBI count is highest for males aged 15-34 (5.47 ± 0.55 million in model 2 and 3.21 ± 0.13 million in model 3). CONCLUSIONS: Projected estimates of TBI in Africa are high, with a burden of anywhere between approximately 6 and 14 million new cases in 2050. This emphasizes the importance of developing accurate surveillance systems of TBI at a population level and public health measures to mitigate the risk and burden of TBI.
Assuntos
Lesões Encefálicas/epidemiologia , Adolescente , Adulto , África/epidemiologia , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Fatores Sexuais , Adulto JovemRESUMO
BACKGROUND AND PURPOSE: To our knowledge there are no studies reporting the use and short-term outcomes of intravenous tissue plasminogen activator (IV-TPA) for the treatment of acute ischaemic stroke (AIS) in people living with HIV. METHODS: The US Nationwide Inpatient Sample (NIS) (2006-2010) was searched for HIV-infected AIS patients treated with IV-TPA. RESULTS: In the NIS, 2.2% (62/2877) of HIV-infected AIS cases were thrombolyzed with IV-TPA (median age 52 years, range 27-78, 32% female, 22% Caucasian) vs. 2.1% (19 335/937 896) of HIV-uninfected cases (median age 72 years, range 17-102 years, 50% female, 74% Caucasian; P = 0.77). There were more deaths in HIV-infected versus uninfected patients with stroke (220/2877, 7.6% vs. 49 089/937 547, 5.2%, P < 0.001) but no difference in the proportion of deaths amongst IV-TPA-treated patients. The age- and sex-adjusted odds ratio for death following IV-TPA administration in HIV-infected versus uninfected patients was 2.26 (95% CI 1.12, 4.58), but the interaction on mortality between HIV and IV-TPA use was not statistically significant, indicating no difference in risk of in-hospital death by HIV serostatus with IV-TPA use. A higher number of HIV-infected patients remained in hospital versus died or were discharged at both 10 and 30 days (P < 0.01 at 10 and 30 days). No difference in the proportion of intracerebral hemorrhage in the two groups was found (P = 0.362). CONCLUSIONS: The in-hospital mortality is higher amongst HIV-infected AIS patients than HIV-uninfected patients. However, the risk of death amongst HIV-infected patients treated with IV-TPA is similar to HIV-uninfected groups.
Assuntos
Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/mortalidade , Infecções por HIV/mortalidade , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/mortalidade , Ativador de Plasminogênio Tecidual/farmacologia , Administração Intravenosa , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/epidemiologia , Comorbidade , Feminino , Infecções por HIV/epidemiologia , Mortalidade Hospitalar , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/epidemiologia , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Receiving a diagnosis of multiple sclerosis (MS) can be stressful; later, patients may conceal their diagnosis. Here, we aimed to (1) assess prevalence of disclosure and concealment behaviors, and (2) explore whether diagnosis experience is associated with later concealment and if MS provider engagement on this topic modifies concealment. METHODS: In a survey-based study, MS patients completed DISCO-MS assessing disclosure and concealment and responded to questions about diagnosis experience and practitioner attention to disclosure. Frequency analysis and Pearson's correlations were used in exploratory analyses. RESULTS: 428 adults with MS participated. 49% (N = 201) conceal their diagnosis. Higher education [t(405) = 3.66, p < 0.001], younger age (r = -0.15, p = 0.002), and shorter disease duration (r = -0.18, p = 0.010) were associated with higher concealment. 39% (N = 159) anticipate negative consequences of disclosure. Individuals reporting positive diagnosis experience (26%, N = 102) were less likely to conceal later in disease course compared to those with negative experience (34%, N = 136) [t(233) = 2.483, p = 0.014]. Patients whose MS providers discussed disclosure (23%, N = 73) anticipated less negative consequences of disclosure [t(323) = 2.475, p = 0.014]. CONCLUSIONS: Diagnosis concealment is common in MS. Favorable diagnosis experience and provider attention to the topic of disclosure throughout the MS disease course may influence diagnosis concealment.
Assuntos
Esclerose Múltipla , Adulto , Humanos , Esclerose Múltipla/diagnóstico , Esclerose Múltipla/epidemiologia , Inquéritos e QuestionáriosRESUMO
BACKGROUND AND PURPOSE: The central vein sign is a promising MR imaging diagnostic biomarker for multiple sclerosis. Recent studies have demonstrated that patients with MS have higher proportions of white matter lesions with the central vein sign compared with those with diseases that mimic MS on MR imaging. However, the clinical application of the central vein sign as a biomarker is limited by interrater differences in the adjudication of the central vein sign as well as the time burden required for the determination of the central vein sign for each lesion in a patient's full MR imaging scan. In this study, we present an automated technique for the detection of the central vein sign in white matter lesions. MATERIALS AND METHODS: Using multimodal MR imaging, the proposed method derives a central vein sign probability, πij, for each lesion, as well as a patient-level central vein sign biomarker, ψi. The method is probabilistic in nature, allows site-specific lesion segmentation methods, and is potentially robust to intersite variability. The proposed algorithm was tested on imaging acquired at the University of Vermont in 16 participants who have MS and 15 participants who do not. RESULTS: By means of the proposed automated technique, participants with MS were found to have significantly higher values of ψ than those without MS (ψMS = 0.55 ± 0.18; ψnon-MS = 0.31 ± 0.12; P < .001). The algorithm was also found to show strong discriminative ability between patients with and without MS, with an area under the curve of 0.88. CONCLUSIONS: The current study presents the first fully automated method for detecting the central vein sign in white matter lesions and demonstrates promising performance in a sample of patients with and without MS.
Assuntos
Algoritmos , Esclerose Múltipla/diagnóstico por imagem , Neuroimagem/métodos , Veias/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/patologia , Veias/patologia , Substância Branca/patologiaRESUMO
BACKGROUND AND PURPOSE: Lesion load is a common biomarker in multiple sclerosis, yet it has historically shown modest association with clinical outcome. Lesion count, which encapsulates the natural history of lesion formation and is thought to provide complementary information, is difficult to assess in patients with confluent (ie, spatially overlapping) lesions. We introduce a statistical technique for cross-sectionally counting pathologically distinct lesions. MATERIALS AND METHODS: MR imaging was used to assess the probability of a lesion at each location. The texture of this map was quantified using a novel technique, and clusters resembling the center of a lesion were counted. Validity compared with a criterion standard count was demonstrated in 60 subjects observed longitudinally, and reliability was determined using 14 scans of a clinically stable subject acquired at 7 sites. RESULTS: The proposed count and the criterion standard count were highly correlated (r = 0.97, P < .001) and not significantly different (t59 = -.83, P = .41), and the variability of the proposed count across repeat scans was equivalent to that of lesion load. After accounting for lesion load and age, lesion count was negatively associated (t58 = -2.73, P < .01) with the Expanded Disability Status Scale. Average lesion size had a higher association with the Expanded Disability Status Scale (r = 0.35, P < .01) than lesion load (r = 0.10, P = .44) or lesion count (r = -.12, P = .36) alone. CONCLUSIONS: This study introduces a novel technique for counting pathologically distinct lesions using cross-sectional data and demonstrates its ability to recover obscured longitudinal information. The proposed count allows more accurate estimation of lesion size, which correlated more closely with disability scores than either lesion load or lesion count alone.
Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos TestesRESUMO
BACKGROUND AND PURPOSE: MR imaging can be used to measure structural changes in the brains of individuals with multiple sclerosis and is essential for diagnosis, longitudinal monitoring, and therapy evaluation. The North American Imaging in Multiple Sclerosis Cooperative steering committee developed a uniform high-resolution 3T MR imaging protocol relevant to the quantification of cerebral lesions and atrophy and implemented it at 7 sites across the United States. To assess intersite variability in scan data, we imaged a volunteer with relapsing-remitting MS with a scan-rescan at each site. MATERIALS AND METHODS: All imaging was acquired on Siemens scanners (4 Skyra, 2 Tim Trio, and 1 Verio). Expert segmentations were manually obtained for T1-hypointense and T2 (FLAIR) hyperintense lesions. Several automated lesion-detection and whole-brain, cortical, and deep gray matter volumetric pipelines were applied. Statistical analyses were conducted to assess variability across sites, as well as systematic biases in the volumetric measurements that were site-related. RESULTS: Systematic biases due to site differences in expert-traced lesion measurements were significant (P < .01 for both T1 and T2 lesion volumes), with site explaining >90% of the variation (range, 13.0-16.4 mL in T1 and 15.9-20.1 mL in T2) in lesion volumes. Site also explained >80% of the variation in most automated volumetric measurements. Output measures clustered according to scanner models, with similar results from the Skyra versus the other 2 units. CONCLUSIONS: Even in multicenter studies with consistent scanner field strength and manufacturer after protocol harmonization, systematic differences can lead to severe biases in volumetric analyses.
Assuntos
Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética/normas , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Neuroimagem/normas , Adulto , Encéfalo/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Recidivante-Remitente/patologia , Neuroimagem/métodos , Reprodutibilidade dos TestesRESUMO
BACKGROUND AND PURPOSE: Detecting incidence and enlargement of lesions is essential in monitoring the progression of MS. In clinical trials, lesion load is observed by manually segmenting and comparing serial MR images, which is time consuming, costly, and prone to inter- and intraobserver variability. Subtracting images from consecutive time points nulls stable lesions, leaving only new lesion activity. We propose SuBLIME, an automated method for segmenting incident lesion voxels. MATERIALS AND METHODS: We used logistic regression models incorporating multiple MR imaging sequences and subtraction images from consecutive longitudinal studies to estimate voxel-level probabilities of lesion incidence. We used T1-weighted, T2-weighted, FLAIR, and PD volumes from a total of 110 MR imaging studies from 10 subjects. RESULTS: To assess the performance of the model, we assigned 5 subjects to a training set and the remaining 5 to a validation set. With SuBLIME, lesion incidence is detected and delineated in the validation set with an AUC of 99% (95% CI [97%, 100%]) at the voxel level. CONCLUSIONS: This fully automated and computationally fast method allows sensitive and specific detection of lesion incidence that can be applied to large collections of images. Using the explicit form of the statistical model, SuBLIME can easily be adapted to cases when more or fewer imaging sequences are available.
Assuntos
Algoritmos , Encefalopatias/patologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Esclerose Múltipla/patologia , Fibras Nervosas Mielinizadas/patologia , Reconhecimento Automatizado de Padrão/métodos , Adulto , Humanos , Aumento da Imagem/métodos , Incidência , Estudos Longitudinais , Pessoa de Meia-Idade , Sensibilidade e EspecificidadeRESUMO
BACKGROUND AND PURPOSE: Disruption of the BBB in MS is associated with the development of new lesions and clinical relapses and signifies the presence of active inflammation. It is most commonly detected as enhancement on MR imaging performed with contrast agents that are costly and occasionally toxic. We investigated whether the BBB status in white matter lesions may be indirectly ascertained via examination of features on T1- and T2-weighted images obtained before the injection of a contrast agent. MATERIALS AND METHODS: We considered 93 brain MR imaging studies on 16 patients that included T1-, T2-, and T2-weighted FLAIR images and predicted voxel wise enhancement after intravenous injection of a gadolinium chelate. We then used these voxel-level predictions to determine the presence or absence of abnormal enhancement anywhere in the brain. RESULTS: On a voxel-by-voxel basis, enhancement can be predicted by using contrast-free measures with an AUC of 0.83 (95% CI, 0.80-0.87). At the whole-brain level, enhancement can be predicted with an AUC of 0.72 (95% CI, 0.62-0.82). CONCLUSIONS: In many cases, breakdown of the BBB in acute MS lesions may be inferred without the need to inject an MR imaging contrast agent. The inference relies on intrinsic properties of tissue damage in acute lesions. Although contrast studies are more accurate, they may sometimes be unnecessary.