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.
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.
This study focuses on the neurophysiological basis of the Triarchic Model of Psychopathy. More specifically, on the neural correlates of the etiological pathways (trait fearlessness and externalizing vulnerability) underlying the expression of distinct psychopathic traits of the Triarchic Model of Psychopathy. The main results suggest that while boldness was associated with reduced brain activity to threat conditioning and a better estimation of the probability of occurrence of a threatening event, disinhibition was associated with reduced brain activity to the occurrence of errors. Thus, we provided evidence for trait fearlessness and externalizing vulnerability as putative etiological mechanisms underlying the expression of boldness and disinhibition psychopathic traits.
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.
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 β-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.
Neuroimaging in Dementia Barkhof, Frederik; Bastos-Leite, António J; Fox, Nick C ...
2011, 20101020, 2011-02-23
eBook
This up-to-date, superbly illustrated book is a practical guide to the effective use of neuroimaging in the patient with cognitive decline. It sets out the key clinical and imaging features of the ...various causes of dementia and directs the reader from clinical presentation to neuroimaging and on to an accurate diagnosis whenever possible. After an introductory chapter on the clinical background, the available "toolbox" of structural and functional neuroimaging techniques is reviewed in detail, including CT, MRI and advanced MR techniques, SPECT and PET, and image analysis methods. The imaging findings in normal ageing are then discussed, followed by a series of chapters that carefully present and analyze the key findings in patients with dementias. Throughout, a practical approach is adopted, geared specifically to the needs of clinicians (neurologists, radiologists, psychiatrists, geriatricians) working in the field of dementia, for whom this book will prove an invaluable resource.
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.
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.
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.
Abstract 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.
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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