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We reviewed 33 original research studies assessing brain perfusion, using consensus guidelines from a "white paper" issued by the International Society for Magnetic Resonance in Medicine Perfusion Study Group and the European Cooperation in Science and Technology Action BM1103 ("Arterial Spin Labelling Initiative in Dementia"; https://www.cost.eu/actions/BM1103/ ). The studies were published between 2011 and 2023 and included participants with subjective cognitive decline plus; neurocognitive disorders, including mild cognitive impairment (MCI), Alzheimer's disease (AD), frontotemporal lobar degeneration (FTLD), dementia with Lewy bodies (DLB) and vascular cognitive impairment (VCI); as well as schizophrenia spectrum disorders, bipolar and major depressive disorders, autism spectrum disorder, attention-deficit/hyperactivity disorder, panic disorder and alcohol use disorder. Hypoperfusion associated with cognitive impairment was the major finding across the spectrum of cognitive decline. Regional hyperperfusion also was reported in MCI, AD, frontotemporal dementia phenocopy syndrome and VCI. Hypoperfused structures found to aid in diagnosing AD included the precunei and adjacent posterior cingulate cortices. Hypoperfused structures found to better diagnose patients with FTLD were the anterior cingulate cortices and frontal regions. Hypoperfusion in patients with DLB was found to relatively spare the temporal lobes, even after correction for partial volume effects. Hyperperfusion in the temporal cortices and hypoperfusion in the prefrontal and anterior cingulate cortices were found in patients with schizophrenia, most of whom were on medication and at the chronic stage of illness. Infratentorial structures were found to be abnormally perfused in patients with bipolar or major depressive disorders. Brain perfusion abnormalities were helpful in diagnosing most neurocognitive disorders. Abnormalities reported in VCI and the remaining mental disorders were heterogeneous and not generalisable.
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Trastornos Mentales , Marcadores de Spin , Humanos , Trastornos Mentales/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Circulación Cerebrovascular , Disfunción Cognitiva/diagnóstico por imagenRESUMEN
This article focuses on clinical applications of arterial spin labeling (ASL) and is part of a wider effort from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group to update and expand on the recommendations provided in the 2015 ASL consensus paper. Although the 2015 consensus paper provided general guidelines for clinical applications of ASL MRI, there was a lack of guidance on disease-specific parameters. Since that time, the clinical availability and clinical demand for ASL MRI has increased. This position paper provides guidance on using ASL in specific clinical scenarios, including acute ischemic stroke and steno-occlusive disease, arteriovenous malformations and fistulas, brain tumors, neurodegenerative disease, seizures/epilepsy, and pediatric neuroradiology applications, focusing on disease-specific considerations for sequence optimization and interpretation. We present several neuroradiological applications in which ASL provides unique information essential for making the diagnosis. This guidance is intended for anyone interested in using ASL in a routine clinical setting (i.e., on a single-subject basis rather than in cohort studies) building on the previous ASL consensus review.
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Accidente Cerebrovascular Isquémico , Enfermedades Neurodegenerativas , Humanos , Niño , Angiografía por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Marcadores de Spin , Perfusión , Circulación CerebrovascularRESUMEN
INTRODUCTION: Abnormalities in the experience of space and time are fundamental to understanding schizophrenia spectrum disorders, but the precise relation between such abnormalities and psychopathological symptoms is still unclear. Therefore, the aim of our study was to introduce a novel scale for space and time experience in psychosis (STEP), specifically devised to assess schizophrenia spectrum disorders. METHODS: The STEP scale is a semiquantitative instrument developed on the basis of several items from previous scales and phenomenological reports addressing the experience of space and time. We applied the STEP scale to three groups of subjects (patients with schizophrenia spectrum disorders, patients with predominant affective symptoms, and healthy control subjects), to whom we also applied other more general psychopathological scales, such as the Positive and Negative Syndrome Scale and the Ego-Psychopathology Inventory. RESULTS: Patients with schizophrenia spectrum disorders scored significantly higher on general psychopatho
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Trastornos Psicóticos , Esquizofrenia , Humanos , Escalas de Valoración Psiquiátrica , Psicometría , Psicopatología , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/psicología , Reproducibilidad de los Resultados , Esquizofrenia/diagnósticoRESUMEN
Perivascular spaces (PVS) of the brain, often called Virchow-Robin spaces, comprise fluid, cells and connective tissue, and are externally limited by astrocytic endfeet. PVS are involved in clearing brain waste and belong to the "glymphatic" system and/or the "intramural periarterial drainage" pathway through the basement membranes of the arteries. Related brain waste clearance systems include the blood-brain barrier, scavenger cells, cerebrospinal fluid, perineural lymphatic drainage pathways and the newly characterised meningeal lymphatic vessels. Any functional abnormality of PVS or related clearance systems might lead to accumulation of brain waste. It has been postulated that PVS enlargement can be secondary to accumulation of ß-amyloid. Lack of integrity of the vascular wall, microbleeds, cerebral amyloid angiopathy (CAA) and enlarged PVS often occur in the preclinical stages of Alzheimer's disease, preceding substantial brain atrophy. PVS enlargement in the form of état criblé at the basal ganglia has also been considered to reflect focal atrophy, most probably secondary to ischaemic injury, based upon both pathological and imaging arguments. In addition, distinct topographic patterns of enlarged PVS are related to different types of microangiopathy: CAA is linked to enlarged juxtacortical PVS, whereas subjects with vascular risk factors tend to have enlarged PVS in the basal ganglia. Therefore, enlarged PVS are progressively being regarded as a marker of neurodegenerative and cerebrovascular pathology. The present review addresses the evolving concept of PVS and brain waste clearance systems, the potential relevance of their dysfunction to neurodegenerative and cerebrovascular pathology, and potential therapeutic approaches of interest.
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Sistema Glinfático , Enfermedades Neurodegenerativas , Ganglios Basales , Encéfalo/diagnóstico por imagen , Sistema Glinfático/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Enfermedades Neurodegenerativas/diagnóstico por imagenRESUMEN
Algorithms for computer-aided diagnosis of dementia based on structural MRI have demonstrated high performance in the literature, but are difficult to compare as different data sets and methodology were used for evaluation. In addition, it is unclear how the algorithms would perform on previously unseen data, and thus, how they would perform in clinical practice when there is no real opportunity to adapt the algorithm to the data at hand. To address these comparability, generalizability and clinical applicability issues, we organized a grand challenge that aimed to objectively compare algorithms based on a clinically representative multi-center data set. Using clinical practice as the starting point, the goal was to reproduce the clinical diagnosis. Therefore, we evaluated algorithms for multi-class classification of three diagnostic groups: patients with probable Alzheimer's disease, patients with mild cognitive impairment and healthy controls. The diagnosis based on clinical criteria was used as reference standard, as it was the best available reference despite its known limitations. For evaluation, a previously unseen test set was used consisting of 354 T1-weighted MRI scans with the diagnoses blinded. Fifteen research teams participated with a total of 29 algorithms. The algorithms were trained on a small training set (n=30) and optionally on data from other sources (e.g., the Alzheimer's Disease Neuroimaging Initiative, the Australian Imaging Biomarkers and Lifestyle flagship study of aging). The best performing algorithm yielded an accuracy of 63.0% and an area under the receiver-operating-characteristic curve (AUC) of 78.8%. In general, the best performances were achieved using feature extraction based on voxel-based morphometry or a combination of features that included volume, cortical thickness, shape and intensity. The challenge is open for new submissions via the web-based framework: http://caddementia.grand-challenge.org.
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Algoritmos , Enfermedad de Alzheimer/diagnóstico , Disfunción Cognitiva/diagnóstico , Diagnóstico por Computador/métodos , Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Magnética/métodos , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/clasificación , Disfunción Cognitiva/clasificación , Diagnóstico por Computador/normas , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/normas , Imagen por Resonancia Magnética/normas , Masculino , Persona de Mediana Edad , Sensibilidad y EspecificidadRESUMEN
Intracranial arterial stenosis (IAS) is usually attributable to atherosclerosis and corresponds to the most common cause of stroke worldwide. It is very prevalent among African, Asian, and Hispanic populations. Advancing age, systolic hypertension, diabetes mellitus, high levels of low-density lipoprotein cholesterol, and metabolic syndrome are some of its major risk factors. IAS may be associated with transient or definite neurological symptoms or can be clinically asymptomatic. Transcranial Doppler and magnetic resonance angiography are the most frequently used ancillary examinations for screening and follow-up. Computed tomography angiography can either serve as a screening tool for the detection of IAS or increasingly as a confirmatory test approaching the diagnostic accuracy of catheter digital subtraction angiography, which is still considered the gold (confirmation) standard. The risk of stroke in patients with asymptomatic atherosclerotic IAS is low (up to 6% over a mean follow-up period of approximately 2 years), but the annual risk of stroke recurrence in the presence of a symptomatic stenosis may exceed 20% when the degree of luminal narrowing is 70% or more, recently after an ischemic event, and in women. It is a matter of controversy whether there is a specific type of treatment other than medical management (including aggressive control of vascular risk factors and antiplatelet therapy) that may alter the high risk of stroke recurrence among patients with symptomatic IAS. Endovascular treatment has been thought to be helpful in patients who fail to respond to medical treatment alone, but recent data contradict such expectation.
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Enfermedades Arteriales Cerebrales/complicaciones , Enfermedades Arteriales Cerebrales/epidemiología , Enfermedades Arteriales Cerebrales/fisiopatología , Enfermedades Arteriales Cerebrales/terapia , Constricción Patológica , Humanos , Factores de Riesgo , Accidente Cerebrovascular/etiología , Accidente Cerebrovascular/prevención & controlRESUMEN
Multiple sclerosis (MS) is primarily a white matter disease, but may also involve the gray matter, a feature not often demonstrated in vivo. This report presents the case of a patient with MS and clinical features mimicking frontotemporal dementia due to clear-cut cortical gray matter involvement in the left frontal lobe.
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Demencia/etiología , Demencia/patología , Lóbulo Frontal/patología , Esclerosis Múltiple/complicaciones , Fibras Nerviosas Mielínicas/patología , Femenino , Humanos , Imagen por Resonancia Magnética , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
INTRODUCTION: We aimed to assess the value of a second MR scan in the radiological diagnosis of dementia. METHODS: One hundred twenty subjects with clinical follow-up of at least 1 year with two scans were selected from a cognitive disorders clinic. Scans were reviewed as a single first scan (method A), two unregistered scans presented side-by-side (method B) and a registered pair (method C). Scans were presented to two neuroradiologists and a clinician together with approximate scan interval (if applicable) and age. Raters decided on a main and subtype diagnosis. RESULTS: There was no evidence that differences between methods (expressed as relative odds of a correct response) differed between reviewers (p = 0.17 for degenerative condition or not, p = 0.5 for main diagnosis, p = 0.16 for subtype). Accordingly, results were pooled over reviewers. For distinguishing normal/non-progressors from degenerative conditions, the proportions correctly diagnosed were higher with methods B and C than with A (p = 0.001, both tests). The difference between method B and C was not statistically significant (p = 0.18). For main diagnosis, the proportion of correct diagnoses were highest with method C for all three reviewers; however, this was not statistically significant comparing with method A (p = 0.23) or with method B (p = 0.16). For subtype diagnosis, there was some evidence that method C was better than method A (p = 0.01) and B (p = 0.048). CONCLUSIONS: Serial MRI and registration may improve visual diagnosis in dementia.
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Encéfalo/patología , Demencia/patología , Aumento de la Imagen/métodos , Imagen por Resonancia Magnética/métodos , Reconocimiento de Normas Patrones Automatizadas/métodos , Técnica de Sustracción , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The diagnosis of Alzheimer disease (AD) at an early age of onset may be a challenging task. The diagnosis of such a type of dementia may be even more difficult when concomitant depressive symptoms occur. We report the case of a 51-year-old woman who was admitted at a Psychiatric Day Hospital presenting with depressive symptoms, visuospatial deficits, apraxia, and minor memory loss. The patient underwent long-term antidepressant therapy, but despite the improvement of depressive symptoms, there was progressive cognitive deterioration. Otherwise, the prior clinical history was unremarkable, and there was no family history of dementia. The clinical examination revealed cognitive deficits in several domains. The patient scored 12 in the Mini-Mental State Examination. Routine laboratory tests were normal. Magnetic resonance (MR) imaging showed global brain volume loss more pronounced than would be expected for someone of the patient's age, especially in the precuneus-a pattern of posterior cortical atrophy consistent with the diagnosis of early-onset AD. Images obtained with 99mTc-HMPAO single-photon emission computed tomography (SPECT) also revealed marked brain hypoperfusion involving the left parietal lobe, far beyond the regions of brain volume loss. This clinical case report illustrates the relative contribution of both MR imaging and SPECT for the diagnosis of dementia in a patient with concomitant depressive symptoms. Apart from contributing to the diagnosis of dementia beyond the traditional exclusionary approach, neuroimaging is increasingly being used to classify its particular subtypes. The role of neuroimaging role in AD is also supported by a recent proposal of revised diagnostic criteria, which take into account abnormal biomarkers of disease.
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Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/diagnóstico , Tomografía Computarizada de Emisión de Fotón Único/métodos , Enfermedad de Alzheimer/complicaciones , Encéfalo/diagnóstico por imagen , Trastornos del Conocimiento/etiología , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Escala del Estado Mental , Persona de Mediana Edad , Exametazima de Tecnecio Tc 99mRESUMEN
LEARNING OBJECTIVES: After participating in this activity, learners should be better able to:⢠Assess differences between adult patients with the diagnosis of borderline personality disorder (BPD) and healthy control subjects in terms of empathy and related processes⢠Evaluate the effects of empathy or related processes as factors contributing to abnormal social functioning in BPD ABSTRACT: We reviewed 45 original research studies, published between 2000 and 2019, to assess differences between adult patients with the diagnosis of borderline personality disorder (BPD) and healthy control subjects in terms of empathy and related processes (i.e., theory of mind, mentalizing, social cognition, and emotional intelligence). Thirty-six studies reported deficits of empathy or related processes in patients with BPD. Enhanced emotional empathy in BPD was also reported in eight studies, all of which revealed that patients had increased scores of personal distress on the Interpersonal Reactivity Index self-report questionnaire. Six studies did not find significant differences between patients with BPD and healthy control subjects in terms of empathy or related processes. No study reported enhanced cognitive empathy, social cognition, or emotional intelligence in patients with BPD. We postulate that deficits of empathy or related processes contribute to preempting the formation of stable interpersonal relationships, whereas enhanced emotional empathy might lead to personal (and interpersonal) distress, further contributing to abnormal social functioning in BPD.
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Trastorno de Personalidad Limítrofe/psicología , Empatía , Relaciones Interpersonales , Adulto , Trastorno de Personalidad Limítrofe/diagnóstico , Cognición , Emociones , HumanosRESUMEN
The psychopathic traits boldness, meanness, and disinhibition are theorized to be underlined by trait fearlessness and externalizing vulnerability as etiologic neurobiological processes. However, little is known about the neurophysiological correlates of these traits. In this work, we explored how the three traits are associated with event-related potential (ERP) components targeted at the etiological processes in a partial delayed threat conditioning task and in a go/no-go task. Fifty community-dwelling volunteers (25 women), without history of neurological or psychiatric conditions, were recruited and assessed for psychopathic traits using the triarchic psychopathy measure. Participants performed a threat conditioning task, and a go/no-go task while undergoing an electroencephalography recording. Results from the threat conditioning task showed that boldness was significantly associated with reduced late positive potential. Concerning the go/no-go task, disinhibition was significantly associated with reduced error-related negativity ERP component. Overall, distinct psychopathic traits were found to be associated with distinct neurophysiological correlates of threat conditioning and response inhibition. This is consistent with models of psychopathy entailing trait fearlessness and externalizing proneness, and related brain mechanisms, as distinct processes underlying the expression of psychopathic traits.
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Trastorno de Personalidad Antisocial/fisiopatología , Condicionamiento Clásico/fisiología , Potenciales Evocados/fisiología , Miedo/fisiología , Inhibición Psicológica , Pruebas Neuropsicológicas , Desempeño Psicomotor/fisiología , Adolescente , Adulto , Electroencefalografía , Potenciales Relacionados con Evento P300/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Adulto JovenRESUMEN
We aimed to determine whether variation in the body mass index (BMI)a marker of anorexia nervosa (AN) severityis associated with brain volume changes longitudinally estimated using registration-based methods on serial high-resolution T1-weighted magnetic resonance images (MRI). Fifteen female patients (mean age = 21 years; standard deviation [SD] = 5.7; range: 1533 years) with the diagnosis of AN of the restricting type (AN-r)according to the Diagnostic and Statistic Manual of Mental Disorders, 5th edition criteriaunderwent T1-weighted MRI at baseline and after a mean follow-up period of 11 months (SD = 6.4). We used the brain boundary shift integral (BSI) and the ventricular BSI (VBSI) to estimate volume changes after registering voxels of follow-up onto baseline MRI. Very significant and strong correlations were found between BMI variation and the brain BSI, as well as between BMI variation and the VBSI. After adjustment for age at onset, duration of illness, and the BMI rate of change before baseline MRI, the statistical significance of both associations persisted. Registration-based methods on serial MRI represent an additional tool to estimate AN severity, because they provide measures of brain volume change strongly associated with BMI variation.
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Anorexia Nerviosa/diagnóstico por imagen , Índice de Masa Corporal , Encéfalo/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Adolescente , Adulto , Edad de Inicio , Anorexia Nerviosa/fisiopatología , Encéfalo/fisiopatología , Ventrículos Cerebrales/diagnóstico por imagen , Ventrículos Cerebrales/fisiopatología , Femenino , Estudios de Seguimiento , Humanos , Tamaño de los Órganos , Adulto JovenRESUMEN
Quantitative measurements of brain perfusion are influenced by perfusion-modifiers. Standardization of measurement conditions and correction for important modifiers is essential to improve accuracy and to facilitate the interpretation of perfusion-derived parameters. An extensive literature search was carried out for factors influencing quantitative measurements of perfusion in the human brain unrelated to medication use. A total of 58 perfusion modifiers were categorized into four groups. Several factors (e.g., caffeine, aging, and blood gases) were found to induce a considerable effect on brain perfusion that was consistent across different studies; for other factors, the modifying effect was found to be debatable, due to contradictory results or lack of evidence. Using the results of this review, we propose a standard operating procedure, based on practices already implemented in several research centers. Also, a theory of 'deep MRI physiotyping' is inferred from the combined knowledge of factors influencing brain perfusion as a strategy to reduce variance by taking both personal information and the presence or absence of perfusion modifiers into account. We hypothesize that this will allow to personalize the concept of normality, as well as to reach more rigorous and earlier diagnoses of brain disorders.
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Encéfalo/irrigación sanguínea , Circulación Cerebrovascular/fisiología , Imagen de Perfusión/métodos , Imagen de Perfusión/normas , Humanos , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/normas , Estudios Multicéntricos como AsuntoRESUMEN
BACKGROUND AND PURPOSE: Besides cerebrovascular disease, medial temporal lobe atrophy (MTA), a neuroimaging finding suggestive of degenerative pathology, has been shown in vascular dementia (VaD). However, it is unknown to what extent MTA contributes to the pattern of cognitive impairment observed in VaD. Therefore, our purpose was to investigate the relative contribution of cerebrovascular disease and MTA to cognitive impairment in patients fulfilling diagnostic criteria for VaD. METHODS: We examined 590 patients (374 men; mean age, 73 years; standard deviation, 8) with probable VaD according to the National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria at inclusion into a multicenter clinical trial. Cerebrovascular disease and the degree of MTA were evaluated by using MRI. Cognitive testing included the Mini-Mental State Examination, and the vascular dementia assessment scale. RESULTS: On the basis of the operational definitions for the neuroimaging part of the National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria, 485 (82.2%) patients had small vessel VaD and 153 (25.9%) had large vessel VaD. More than half (59.8%) of the patients had considerable MTA. Multiple linear regression analyses revealed that after correction for sex, age, education, and duration of dementia, neuropsychological tests showed that patients with higher grades of MTA or large vessel VaD had significantly worse general cognitive and executive functioning, whereas associations with small vessel disease were restricted to worse executive functioning. CONCLUSIONS: Both MTA and large vessel disease contribute to global cognitive impairment in VaD. Small vessel disease contributes to executive dysfunction.
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Atrofia , Trastornos Cerebrovasculares/diagnóstico , Trastornos Cerebrovasculares/patología , Trastornos del Conocimiento/diagnóstico , Trastornos del Conocimiento/patología , Demencia Vascular/diagnóstico , Demencia Vascular/patología , Imagen por Resonancia Magnética/métodos , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/patología , Lóbulo Temporal/patología , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/patología , Cognición , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND AND PURPOSE: Infratentorial abnormalities may cause cognitive deficits, but current research criteria for vascular dementia (VaD) do not consider them. Our purposes were to determine the prevalence of infratentorial abnormalities in VaD, their relation with supratentorial abnormalities, and whether they are relevant to cognition. METHODS: We examined 182 patients (120 men, mean age=73 years, SD=8) with probable VaD at inclusion into a multicenter clinical trial. MRI scans were evaluated for infratentorial vascular abnormalities, midbrain atrophy, cerebellar atrophy, basilar artery diameter and tortuosity, and supratentorial abnormalities. Cognitive testing included the mini-mental state examination (MMSE) and the vascular dementia assessment scale (VaDAS-cog). RESULTS: One hundred forty-one (77.5%) patients had infratentorial abnormalities: 119 (65.4%) had focal infratentorial vascular lesions, 65 (35.7%) had diffuse pontine vascular abnormalities hyperintense on T2-weighted images, 20 (11.0%) had midbrain atrophy, and 16 (8.8%) had cerebellar atrophy. Significant correlations were found between number of infratentorial vascular lesions and basilar artery diameter (rs=0.26; P<0.0001), infratentorial and basal ganglia (including thalamus) vascular abnormalities (rs=0.30; P<0.0001), as well as between midbrain atrophy and global supratentorial atrophy (rs=0.27; P<0.0001). Infratentorial vascular abnormalities and cerebellar atrophy were not significantly associated with cognitive impairment. Patients with midbrain atrophy performed worse on cognitive tests than those without midbrain atrophy. After correction for sex, age, education, supratentorial abnormalities, and center, midbrain atrophy remained significantly associated with lower MMSE scores (P<0.05). CONCLUSIONS: Infratentorial abnormalities often occur in patients with VaD, but only midbrain atrophy was found to be relevant to cognition.
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Demencia Vascular/diagnóstico , Demencia Vascular/patología , Imagen por Resonancia Magnética/métodos , Anciano , Anciano de 80 o más Años , Atrofia , Encéfalo/patología , Cognición , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Estadísticos , Análisis de RegresiónAsunto(s)
Coartación Aórtica , Anomalías del Ojo , Síndromes Neurocutáneos , Coartación Aórtica/diagnóstico , Coartación Aórtica/tratamiento farmacológico , Anomalías del Ojo/diagnóstico , Anomalías del Ojo/tratamiento farmacológico , Glucocorticoides/administración & dosificación , Humanos , Recién Nacido , Imagen por Resonancia Magnética , Masculino , Síndromes Neurocutáneos/diagnóstico , Síndromes Neurocutáneos/tratamiento farmacológico , Prednisolona/administración & dosificación , SíndromeRESUMEN
We report the first stochastic dynamic causal modeling (sDCM) study of effective connectivity within the default mode network (DMN) in schizophrenia. Thirty-three patients (9 women, mean age = 25.0 years, SD = 5) with a first episode of psychosis and diagnosis of schizophrenia--according to the Diagnostic and Statistic Manual of Mental Disorders, 4th edition, revised criteria--were studied. Fifteen healthy control subjects (4 women, mean age = 24.6 years, SD = 4) were included for comparison. All subjects underwent resting state functional magnetic resonance imaging (fMRI) interspersed with 2 periods of continuous picture viewing. The anterior frontal (AF), posterior cingulate (PC), and the left and right parietal nodes of the DMN were localized in an unbiased fashion using data from 16 independent healthy volunteers (using an identical fMRI protocol). We used sDCM to estimate directed connections between and within nodes of the DMN, which were subsequently compared with t tests at the between subject level. The excitatory effect of the PC node on the AF node and the inhibitory self-connection of the AF node were significantly weaker in patients (mean values = 0.013 and -0.048 Hz, SD = 0.09 and 0.05, respectively) relative to healthy subjects (mean values = 0.084 and -0.088 Hz, SD = 0.15 and 0.77, respectively; P < .05). In summary, sDCM revealed reduced effective connectivity to the AF node of the DMN--reflecting a reduced postsynaptic efficacy of prefrontal afferents--in patients with first-episode schizophrenia.
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Lóbulo Frontal/fisiopatología , Giro del Cíngulo/fisiopatología , Vías Nerviosas/fisiopatología , Lóbulo Parietal/fisiopatología , Esquizofrenia/fisiopatología , Adulto , Estudios de Casos y Controles , Causalidad , Femenino , Neuroimagen Funcional , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Modelos Teóricos , Procesos Estocásticos , Adulto JovenRESUMEN
Familial Alzheimer's disease (FAD) treatment trials raise interest in the variable occurrence of cerebral amyloid angiopathy (CAA); an emerging important factor in amyloid-modifying therapy. Previous pathological studies reported particularly severe CAA with postcodon 200 PSEN1 mutations and amyloid beta coding domain APP mutations. As CAA may manifest as white matter hyperintensities (WMH) on magnetic resonance imaging, particularly posteriorly, we investigated WMH in 52 symptomatic FAD patients for associations with mutation position. WMH were visually rated in 39 PSEN1 (18 precodon 200); 13 APP mutation carriers and 25 healthy controls. Ten PSEN1 mutation carriers (5 precodon 200) had postmortem examination. Increased WMH were observed in the PSEN1 postcodon 200 group and in the single APP patient with an amyloid beta coding domain (p.Ala692Gly, Flemish) mutation. WMH burden on MRI correlated with severity of CAA and cotton wool plaques in several areas. The precodon 200 group had younger ages at onset, decreased axonal density and/or integrity, and a greater T-lymphocytic response in occipital deep white matter. Mutation site contributes to the phenotypic and pathological heterogeneity witnessed in FAD.
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Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Angiopatía Amiloide Cerebral/genética , Angiopatía Amiloide Cerebral/patología , Sustancia Blanca/patología , Adulto , Precursor de Proteína beta-Amiloide/genética , Apolipoproteínas E/genética , Codón/genética , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Mutación , Presenilina-1/genética , Estudios RetrospectivosRESUMEN
BACKGROUND AND PURPOSE: The criteria of the National Institute of Neurological Disorders and Stroke (NINDS)-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN) include thalamic lesions for the diagnosis of vascular dementia (VaD). Although studies concerning VaD and brain aging advocate the use of fluid-attenuated inversion recovery (FLAIR) or T2-weighted images (T2-WI) to detect ischemic lesions, none compared the sensitivity of these sequences to depict thalamic lesions. METHODS: We performed a blinded review of T2-WI and FLAIR images in 73 patients fulfilling the radiological part of the NINDS-AIREN criteria (mean age, 71 years; range, 49 to 83 years). This sample was drawn from a large multicenter trial on VaD and was expected to have a high prevalence of thalamic lesions. In a side-by-side review, including T1-weighted images as well, lesions were classified according to presumed underlying pathology. RESULTS: The total number of thalamic lesions was 214. Two hundred eight (97%) were detected on T2-WI, but only 117 (55%) were detected on FLAIR (chi(2)=5.1; P<0.05). Although the mean size of lesions detected on T2-WI and not on FLAIR (4.4 mm) was significantly lower than the mean size of lesions detected on both sequences (6.7 mm) (P<0.001), 5 of the 29 lesions >10 mm on T2-WI were not visible on FLAIR. FLAIR detected only 81 (51%) of the 158 probable ischemic lesions and 30 (60%) of the 50 probable microbleeds. CONCLUSIONS: FLAIR should not be used as the only T2-weighted sequence to detect thalamic lesions in patients suspected of having VaD.