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Results for “Neuroimaging”

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PubMed2004

Lateralization on neuroimaging does not differentiate frontotemporal lobar degeneration from Alzheimer's disease.

Lateralization on neuroimaging was compared in cases of frontotemporal lobar degeneration (FTLD; n = 10) and cases of definite Alzheimer's disease (AD; n = 17). All of the cases were pathologically confirmed and semi-quantitative and statistical parametric mapping methods were employed. Seven of the 10 FTLD cases had lateralization on at least one neuroimaging modality: single photon emission computerized tomography (SPECT), MRI, or CT. All 6/6 FTLD cases with SPECT showed lateralization. MRI results generally agreed with SPECT findings. Three of 4 FTLD cases had lateralized atrophy on CT. For the AD cases, 10/17 SPECTs, 2/7 MRIs, and 1/9 CTs showed lateralized findings. Of the neuroimaging modalities utilized, SPECT was the most sensitive in detecting lateralization.

Alzheimer Disease↗

PubMed2000

Neuroimaging in deteriorating patients with cerebellar infarcts and mass effect.

BACKGROUND AND PURPOSE: The decision to proceed with surgery in cerebellar infarct with mass effect (CIMASS) in deteriorating patients is based on clinical features. The potential role of neuroimaging in predicting deterioration has not been systematically studied. In this study we determine the role of neuroimaging in predicting deterioration in CIMASS. METHODS: -We retrospectively reviewed the clinical and neuroimaging features in 90 patients with cerebellar infarcts. We selected for detailed analysis CIMASS in 35 patients. RESULTS: Eighteen patients remained stable and 17 deteriorated. Of these 17 patients, 8 were treated conservatively and 9 had surgery. Radiological features indicative of progression were more common in deteriorating patients compared with stable patients: fourth ventricular shift (82.3% versus 50%, P:=0.075, OR=4. 67), hydrocephalus (76.5% versus 11.1%, P:=0.0001, OR=26), brain stem deformity (47% versus 5.6%, P:=0.0065, OR=15.1), and basal cistern compression (35.3% versus 0%, P:=0.0076, OR=20.91). Differences in upward displacement of the aqueduct and pontomesencephalic junction from Twining's line, tonsillar descent on sagittal MRI, and infarct volumes between stable and deteriorating patients were not statistically significant. CONCLUSIONS: Hydrocephalus, brain stem deformity, and basal cistern compression may herald deterioration in CIMASS. Admission to a neurological-neurosurgical intensive care unit and consideration of preemptive surgery are warranted in these patients. Vertical displacement of tonsils or aqueduct, demonstrated by MR imaging, did not predict deterioration.

Brain Stem Infarctions↗

PubMed1997

Repetitive and non-repetitive violent offending behaviour in male patients in a maximum security mental hospital--clinical and neuroimaging findings.

OBJECTIVE: To examine if different violent offending behaviours are associated with different clinical and neuroimaging profiles. METHOD: Thirty-nine schizophrenic and schizoaffective offenders from a maximum security mental hospital-20 repetitive violent offenders (RVOs) and 19 non-repetitive violent offenders (NRVOs)-were selected for clinical and neuroimaging assessments. RESULTS: Both groups had positive family history of mental illness and violence. Age, diagnosis, duration of illness, victim profiles and use of weapons at the time of the index offence were similar. RVOs had a higher prevalence of early parental separation, juvenile conduct problem, previous convictions of crimes not involving violence, impulsive suicide attempts, delusion of their lives being threatened at the time of the index offence and electroencephalographic (EEG) abnormalities localized to temporal lobes. NRVOs had a higher prevalence of sexual inexperience and command hallucinations to kill at the time of the index offence. Asymmetric gyral patterns at the temporo-parietal region were particularly common in RVOs and absent in NRVOs. Non-specific white matter changes in magnetic resonance imaging (MRI) and generalized cortical hypometabolism in positron emission tomography (PET) were present in both groups. CONCLUSIONS: Different structural and metabolic changes in the brain were associated with different violent offending behaviours. The complex interaction between violent behaviour, clinical features and neuroimaging findings in schizophrenia requires further studies.

Adult↗

PubMed2002

Neuroimaging in dementia with Lewy bodies: metabolism, neurochemistry, and morphology.

Dementia with Lewy bodies (DLB) is recognized as one of the most common forms of neurodegenerative dementia. Neuroimaging contributes to a better understanding of the pathophysiology of DLB by examining alterations in brain metabolism, neurochemisty, and morphology in living patients. Neuroimaging can provide objective and quantifiable antemortem markers for the presence of and the progression of DLB and permits differentiation from other dementias. This article reviews current neuroimaging findings in DLB with particular attention to occipital hypometabolism, dopaminergic and cholinergic deficits, and medial temporal lobe atrophy as measured by positron emission tomography, single-photon emission computed tomography, and magnetic resonance imaging.

Aged↗

PubMed2006

Diagnostic issues in dementia: neuroimaging as a surrogate marker of disease.

Structural neuroimaging is a routine component of the diagnostic evaluation of dementia that is used to rule out potential causes of mental impairment, whereas functional imaging can differentiate different forms of dementia. Neuroimaging also offers promise as a surrogate marker for clinical trials, and new technologies have been developed to provide measures of amyloid plaques and neurofibrillary tangles, the neuropathological hallmarks of Alzheimer's disease. Combining imaging with genetic risk data will likely improve diagnostic accuracy. These new findings warrant reconsideration of current guidelines on the use of neuroimaging in diagnosis and research in dementia.

Aged↗

PubMed2005

Neuroimaging determinants of cognitive performances in stroke associated with small vessel disease.

BACKGROUND AND PURPOSE: Controversies still exist as to the neuroimaging determinants of cognitive impairment in cerebral small vessel disease (SVD). The authors studied the neuroimaging correlates of cognitive performances among patients with stroke associated with SVD. METHODS: The authors per formed cerebral computed tomography, magnetic resonance imaging, and diffusion-weighted imaging among 74 consecutive patients admitted to the acute stroke unit because of stroke associated with SVD. They examined the association between cognitive performances and the following neuroimaging features: volume of white matter changes (WMC), multiplicity of lacunae, location of lacunae, total cerebral atrophy, and frontal and medial temporal lobe atrophy. RESULTS: Apart from age and education, univariate linear regression analyses revealed that WMC volume, presence of thalamic lacunae, cerebral atrophy, and left frontal lobe atrophy predicted performance on the Mini-Mental State Examination while WMC volume, presence of thalamic infarcts, cerebral atrophy, and frontal lobe atrophy of both sides predicted performance on the Mattis Dementia Rating Scale-Initiation/Preservation subscale. In the multivariate analyses, education (R2=0.22, P<.001), left frontal lobe atrophy (R2=0.10, P=.004), and presence of thalamic lacunae (R2=0.04, P=.049) were found to predict performance on the Mini-Mental State Examination while age (R2=0.23, P<.001) and presence of thalamic lacunae (R2=0.08, P=.011) were found to predict performance on the Mattis Dementia Rating Scale-Initiation/Preservation. CONCLUSIONS: Among patients with stroke associated with SVD, thalamic lacunae and frontal lobe atrophy are key determinants of cognitive performances.

Age Factors↗

PubMed2000

Neuroimaging of recovery of function after stroke: implications for rehabilitation.

Stroke is a leading cause of morbidity and mortality in individuals. Many patients have good functional recovery after stroke. The mechanisms of recovery remain largely unknown. Neuroimaging of patients recovering from stroke may provide important insight into the mechanisms of recovery as well as assist in the development of new rehabilitation techniques. The first part of this article reviews previous neuroimaging studies that have monitored the reorganization within the motor and language areas after stroke. In the second section, a unifying theory based on John Hughlings Jackson's "Principles of Compensation" is presented as a possible theory for recovery of function. In the final portion of the article, possible implications and future applications of neuroimaging studies for rehabilitation are presented.

Animals↗

PubMed2006

Neuroimaging studies of emotional responses in PTSD.

Neuroimaging research offers a powerful and noninvasive means to understand healthy as well as dysregulated emotional processing in healthy subjects and PTSD patients. Functional neuroimaging findings suggest specific roles for subregions of the medial prefrontal (mPFC), orbito frontal (OFC), anterior cingulate (ACC), and insular cortices as well as the sublenticular extended amygdala (SLEA) and hippocampus in various components of emotional processing. Some of the same regions appear to be associated with emotional response to trauma, and with symptom formation in PTSD. Neuroimaging findings of emotional processing in healthy subjects and PTSD patients are discussed, addressing the specific roles of cortical regions like mPFC, ACC, and insula, and their potential contribution to PTSD pathophysiology. Processes of cognitive-emotional interactions and social emotions are discussed in an attempt to synthesize the prefrontal findings in healthy subjects and PTSD patients. Further links between functional neuroanatomy of emotional responses and neuroendocrine stress regulation are proposed.

Brain↗

PubMed2005

Frequency and prediction of abnormal findings on neuroimaging of infants with bulging anterior fontanelles.

OBJECTIVES: This study sought to determine the frequency of clinically significant abnormal findings on neuroimaging using neurosonography (NS) in infants with bulging anterior fontanelles (BAFs) and to identify infants at high or low risk for clinically significant abnormal findings on neuroimaging. METHODS: NS was performed in 45 consecutive infants with BAFs brought to the emergency department of a tertiary care hospital. NS reports were categorized as normal, clinically insignificant abnormal, or clinically significant abnormal. For each patient, demographic data, laboratory test results, and clinical diagnosis and outcome were obtained for analysis. RESULTS: Eighteen febrile and 27 nonfebrile infants with BAFs were evaluated. Clinically significant abnormal findings on NS were noted in 16 of 45 patients (36%), five of whom were febrile and 11 of whom were nonfebrile. Brain edema resulting from infection was the most common finding on NS. Univariate analysis indicated that age younger than two months in febrile patients and abnormal findings on neurologic examination in nonfebrile patients were significant clinical predictors for clinically significant abnormal findings on NS in infants with BAFs. Patients presenting with either of these clinical predictors were identified as high risk for abnormal findings on NS. Of the high-risk patients, 15 of 17 patients (88%) had clinically significant abnormal findings on NS, compared with one of 28 patients (4%) in the low-risk group. CONCLUSIONS: This study shows a 36% prevalence of clinically significant abnormal findings on NS in infants with BAFs. Emergent neuroimaging should be considered for infants who meet high-risk criteria: 1) febrile children younger than two months or 2) nonfebrile children with abnormal findings on neurologic examination.

Brain Edema↗

PubMed1997

Temporal lobe epilepsy in childhood: clinical, EEG, and neuroimaging findings and syndrome classification in a cohort with new-onset seizures.

Sixty-three children with new-onset temporal lobe epilepsy (TLE) underwent extensive clinical, EEG, and neuroimaging investigation as part of a prospective, community-based cohort study of the natural history of TLE in childhood. Complex partial seizures occurred in 94% of the children, and tonic-clonic seizures occurred in 14%. Developmental, behavioral, or learning problems were present in 38%. Eighteen children (29%) had a significant illness/event prior to the onset of TLE, including febrile status epilepticus in seven, meningitis in four, respiratory arrest in two, and head injury in one. Magnetic resonance imaging or computed tomography revealed structural abnormalities of the temporal lobe in 24 children (38%), including hippocampal sclerosis (HS) in 13 and tumor in eight. There was a strong association between HS and a history of significant illness/event prior to the onset of TLE (p < 0.001). Analysis of past history and neuroimaging findings led us to propose three etiologically defined subgroups of TLE; developmental TLE (10 children with long-standing, nonprogressive temporal lobe tumors and malformations), TLE with HS/significant antecedents (18 children with HS or a history of a significant illness/event), and cryptogenic TLE (34 children with normal neuroimaging findings and no significant past history). Etiologic differences between children with new-onset TLE may confer prognostic information that will be useful for counselling families and planning treatment.

Anticonvulsants↗

PubMed2004

The RUMBA software: tools for neuroimaging data analysis.

The enormous scale and complexity of data sets in functional neuroimaging makes it crucial to have well-designed and flexible software for image processing, modeling, and statistical analysis. At present, researchers must choose between general purpose scientific computing environments (e.g., Splus and Matlab), and specialized human brain mapping packages that implement particular analysis strategies (e.g., AFNI, SPM, VoxBo, FSL or FIASCO). For the vast majority of users in Human Brain Mapping and Cognitive Neuroscience, general purpose computing environments provide an insufficient framework for a complex data-analysis regime. On the other hand, the operational particulars of more specialized neuroimaging analysis packages are difficult or impossible to modify and provide little transparency or flexibility to the user for approaches other than massively multiple comparisons based on inferential statistics derived from linear models. In order to address these problems, we have developed open-source software that allows a wide array of data analysis procedures. The RUMBA software includes programming tools that simplify the development of novel methods, and accommodates data in several standard image formats. A scripting interface, along with programming libraries, defines a number of useful analytic procedures, and provides an interface to data analysis procedures. The software also supports a graphical functional programming environment for implementing data analysis streams based on modular functional components. With these features, the RUMBA software provides researchers programmability, reusability, modular analysis tools, novel data analysis streams, and an analysis environment in which multiple approaches can be contrasted and compared. The RUMBA software retains the flexibility of general scientific computing environments while adding a framework in which both experts and novices can develop and adapt neuroimaging-specific analyses.

Algorithms↗

PubMed2000

Neuroimaging in delirium and related conditions.

Delirium is one of the most fascinating and poorly understood syndromes in medicine. To a large extent, attempts to study the pathophysiology of delirium have been hampered by the many different types of delirium and their variable symptom expression. The emergence of sophisticated brain imaging methodologies has made it possible to move beyond diagnostic considerations and investigate the neurobiology of specific symptom clusters observed in delirium and related conditions. In this review, neuroimaging findings of relevance to delirium are interpreted in relation to phenomenologically similar symptom states as well as clinical diagnoses. A promising approach in this regard is to combine neuroimaging techniques with symptom-provoking pharmacologic challenge paradigms. Such symptom-oriented neuroimaging studies hold particular promise for improving our understanding of the pathophysiology of delirium and its treatment.

Brain↗

PubMed2000

Neuroimaging in children with newly diagnosed epilepsy: A community-based study.

BACKGROUND: Neuroimaging is generally considered a part of the evaluation of seizures and epilepsy. There is limited information about its current use in the initial evaluation of pediatric epilepsy and about its yield during the initial diagnosis of epilepsy. We describe the patterns in the use and yield of diagnostic imaging in children with newly diagnosed epilepsy in a community-based study. METHODS: Children were recruited when first diagnosed with epilepsy by participating physicians in Connecticut (1993-1997). Definitions for etiology and underlying epilepsy syndromes are as published by the International League Against Epilepsy. RESULTS: Of 613 children, 488 (79.6%) had imaging: 388 (63. 3%) magnetic resonance imaging, 197 (32.1%) computed tomography scans, and 97 (15.8%) both. Half of children with idiopathic generalized epilepsy had imaging studies compared with 70% to 100% of children with other forms of epilepsy, depending on the specific type. Etiologically relevant abnormalities were found in 62 (12.7% of those imaged). Fourteen of these children had otherwise completely normal presentations and histories. Their abnormalities included tuberous sclerosis (N = 4), tumors (N = 2), an arteriovenous malformation later diagnosed as a tumor, a cavernous angioma, cerebral malformations (N = 3), and other abnormalities (N = 3). Thirteen of the 14 had partial seizures and 12 had focal electroencephalographic (EEG) findings. Only 1 had neither. CONCLUSIONS: In children with newly diagnosed epilepsy, neuroimaging reveals a small but significant number of serious abnormalities not previously suspected. Most of these children have partial seizures or focal EEG abnormalities. Neuroimaging should be considered during the evaluation of children with newly diagnosed epilepsy, especially for those with neurologic deficits or partial seizures or focal EEG abnormalities that are not part of an idiopathic localization-related epilepsy syndrome.

Child↗

PubMed2006

Cerebral palsy in a term population: risk factors and neuroimaging findings.

OBJECTIVE: The purpose of this work was to study risk factors and neuroimaging characteristics of cerebral palsy in term and near-term infants. PATIENTS AND METHODS: Among a cohort of 334,339 infants > or = 36 weeks' gestation born at Kaiser Permanente Medical Care Program in northern California in 1991-2003, we identified infants with cerebral palsy and obtained clinical data from electronic and medical charts. Risk factors for cerebral palsy among infants with different brain abnormalities were compared using polytomous logistic regression. RESULTS: Of 377 infants with cerebral palsy (prevalence: 1.1 per 1000), 273 (72%) received a head computed tomography or MRI. Abnormalities included focal arterial infarction (22%), brain malformation (14%), and periventricular white matter abnormalities (12%). Independent risk factors for cerebral palsy were maternal age > 35, black race, and intrauterine growth restriction. Intrauterine growth restriction was more strongly associated with periventricular white matter injury than with other neuroimaging findings. Nighttime delivery was associated with cerebral palsy accompanied by generalized brain atrophy but not with cerebral palsy accompanied by other brain lesions. CONCLUSIONS: Cerebral palsy is a heterogeneous syndrome with focal arterial infarction and brain malformation representing the most common neuroimaging abnormalities in term and near-term infants. Risk factors for cerebral palsy differ depending on the type of underlying brain abnormality.

Adult↗

PubMed2002

High-resolution spatio-temporal functional neuroimaging of brain activity.

The past decades have shown extraordinary progress in our ability to noninvasively image the functions of the human brain. Of particular interest is the recent trend in combining information from electrophysiological and magnetic resonance imaging, which we termed eMRI, to achieve high-resolution functional neuroimaging in both space and time domains. In this article, we review the recent progress in high-resolution functional neuroimaging, in particular the multimodal integration of electroencephalography (EEG) and magnetic resonance imaging (MRI). The state-of-the-art EEG inverse solutions based on different brain electric source models and various approaches to integrate the information from MRI are reviewed. The remaining challenges, future trends, and potential applications of the high-resolution functional neuroimaging research are discussed.

Action Potentials↗

PubMed2006

A systematic review of the effectiveness and cost-effectiveness of neuroimaging assessments used to visualise the seizure focus in people with refractory epilepsy being considered for surgery.

OBJECTIVE: To review the effectiveness and/or accuracy, cost-effectiveness, and predictive value of neuroimaging of the cerebral cortex to visualise the seizure focus in people with refractory epilepsy being considered for surgery. DATA SOURCES: Electronic databases, Internet searches, hand searching and consultation with experts. METHODS: A systematic review was undertaken according to published guidelines. Results of diagnostic accuracy studies were analysed according to the imaging test evaluated. For each study the proportion of patients who were correctly localised, not localised, partially localised or incorrectly localised by the index test was calculated. Due to the heterogeneity present between studies, statistical pooling was not performed. Instead, a narrative synthesis of results is presented. For studies using multivariate analysis to look at the association of neuroimaging findings and outcome following surgery, all factors considered in the analyses were presented. Studies were grouped according to the neuroimaging technique investigated and the findings discussed with reference to possible sources of heterogeneity between studies. RESULTS: No randomised controlled trials (RCTs) were identified, with the majority of studies evaluating the diagnostic accuracy of various imaging techniques in the localisation of epileptic seizure foci. There was significant heterogeneity (p<0.05) between studies for at least one of the localisation categories (correctly localised, not localised, partially localised and incorrectly localised) for all imaging techniques. Possible explanations for this heterogeneity include differing study designs, index test characteristics, reference standards and population characteristics. Test performance was more promising in studies restricted to patients with temporal lobe epilepsy. Ictal single photon emission computed tomography (SPECT) generally had more correctly localising (70--100%) and fewer non-localising (0--7%) scans than other techniques evaluated in patients with temporal lobe epilepsy. Results for computed tomography and interictal SPECT suggest that these tests are relatively poor at localising the seizure focus. Volumeric magnetic resonance imaging (MRI) and position emission tomography (PET) appear promising, and subtraction ictal single photon emission computed tomography co-registered to magnetic resonance imaging (SISCOM) and magnetic resonance spectrosopy (MRS) less promising than ictal SPECT, but these technologies have been assessed in fewer studies. T2 relaxometry was reported in only one small study with inconclusive results. Seventeen studies (33 evaluations) provided sufficient data on the association of a localised scan with outcome following surgery to calculate a relative risk. The majority of evaluations (24/33) suggested that patients with a correctly or partially localised scan had a better outcome following surgery than those with an incorrectly localised or non-localised scan. However, this association was statistically significant in only three studies, two evaluating routine MRI [(relative risk (RR) 2.74, 95% confidence interval (CI): 1.32 to 5.67; RR 1.28, 95% CI: 1.00 to 1.63] and the other SISCOM (RR 2.12, 95% CI: 1.01, 4.44). Nine studies used multivariate analysis to investigate the association of MRI (7 studies), MRS and volumetric MRI (1 study), PET (3 studies), SPECT (1 study) and SISCOM (3 studies) with the outcome following surgery. There was a trend for localisation of abnormalities to be associated with a beneficial outcome. CONCLUSIONS: Due to the limitations of the included studies, the results of this review do little to inform clinical practice, with insufficient evidence regarding effectiveness and cost-effectiveness of imaging techniques in the work-up for epilepsy surgery. Given the inadequacy of existing data, there is a pressing need for studies investigating the utility of imaging techniques in the work up for epilepsy surgery. The most reliable method to achieve this is the RCT, which could examine the single tests or combinations of tests on patient outcome. The authors suggest that it is important that clinicians, patient groups, policy makers and healthcare/research funders meet and debate the most appropriate way to investigate these technologies.

Cerebral Cortex↗

PubMed1999

Neuroimaging in the developmental disorders: the state of the science.

The developmental disorders of childhood autistic, developmental language, reading (dyslexia), and attention deficit-hyperactivity disorders-manifest with deficits in the traditional behavioral domains of cognition, language, visual-spatial function, attention, and socialization. However, none of these disorders has been associated with characteristic discrete focal lesions or recognized encephaloclastic processes. Developmental cognitive neuroscientists must therefore begin with the spectrum of sometimes divergent behaviors occurring within these disorders and work backward in an attempt to identify the responsible anomalous neural systems. Since the advent of "brain imaging" two decades ago, much effort has focused on identifying brain-behavior correlates in these disorders. The results of these neuropathologic, structural, and functional neuroimaging studies are presented and the reasons for the often divergent findings are discussed. As we approach the end of the Decade of the Brain, current neuroimaging techniques give us the technology for the first time to apply a fundamental cognitive approach to brain-behavior relationships in the developmental disorders, to eliminate the conglomeration of "apples and camels" phenomenon. Researchers are working together to create comparable protocols and to adhere to methods that can be replicated across sites. The future prospects for a greater understanding of the developmental disorders are now much brighter with neuroimaging technology.

Adolescent↗

PubMed1999

A review of database management systems suitable for neuroimaging.

This study comprises a technical assessment of Database Management Systems (DBMS), which may be of use in the analysis of data obtained from human brain mapping procedures. Due to the large expansion of the neuroimaging field, the use of specialized database software to store and process neuroimages and their attached components is inevitable. The advent of multiple software products, a wealth of technical terms and a wide variety of other applications make the choice of a suitable program sometimes difficult. Through the inclusion of some basic and pertinent criteria (e.g., performance, ease of opening, standardization and portability), we present a descriptive comparison of 12 DBMSs currently available in the commercial and public domain. We have compared and tested three main architecture models which are currently available and assessed their potential applications for imaging purposes: relational, object-oriented, and hybrid. The findings of our study demonstrated that the Illustra software was the best suited for a neuroimaging environment because of its intrinsic ability to handle complex and large objects, such as 3D volumes or geometric structures.

Brain Mapping↗