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At least 811 records · Page 45Linked to original sources
PubMed2003

A neuroimaging follow up study of a patient with juvenile central nervous system systemic lupus erythematosus.

BACKGROUND: The course of central nervous system systemic lupus erythematosus (CNS-SLE) is largely unknown. New imaging techniques are available to assist in monitoring the disease course. OBJECTIVE: To report a case of juvenile CNS-SLE, in which magnetic resonance imaging (MRI) was used to assess disease activity. CASE REPORT: A 10-year-old female patient with SLE presented with convulsions; MRI and computed tomography (CT) of the cerebrum disclosed abnormalities. Despite adequate treatment, two years later she had a generalised convulsion, and MRI showed new lesions. MR spectroscopy (MRS) indicated neuronal loss, inflammation, and metabolically compromised tissue; magnetisation transfer imaging (MTI) showed an increase in whole brain lesion load. After exclusion of a malignancy, CNS-SLE was the most likely diagnosis, and cyclophosphamide pulses were administered. Initially, multiple sclerosis (MS)-like lesions regressed, but despite maximal immunosuppressive drugs, new lesions formed and disappeared. When immunosuppressive drugs had been stopped for six months MRI showed improved lesions and MTI histograms. DISCUSSION: In this case report, the anatomical substrate, metabolic aspect, neuroimaging, and clinical course of MS-like lesions in a child with CNS-SLE are described. The way in which radiological techniques can support clinical decision making in this young patient with progressive CNS-SLE is illustrated.

Child↗
PubMed1993

Bilateral occipital calcification, epilepsy and coeliac disease: clinical and neuroimaging features of a new syndrome.

Twenty patients affected by bilateral occipital cortical-subcortical calcification (BOC) are described, 19 (95%) had epilepsy. In 8 of 16 cases studied, intestinal biopsy revealed coeliac disease. Fourteen patients had occipital partial epilepsy with a relatively benign outcome, while 4 patients were affected by a severe form of epilepsy, with very frequent, drug-resistant, generalised and partial seizures with mental deterioration. One patient had a single episode of convulsive status epilepticus at four months of age. The neurological examination was normal in all patients. CT showed flocculo-nodular, cortico-subcortical BOC, without enhancement and without lobar or hemispheric atrophy. MRI was normal. The clinical and neuroimaging features of these patients are different therefore from those with the Sturge-Weber Syndrome. The study confirms a high prevalence of coliac disease in patients with BOC, but the relationship between these two pathologies still needs to be clarified.

Adolescent↗
PubMed1997

Eosinophilia-myalgia syndrome: selective cognitive impairment, longitudinal effects, and neuroimaging findings.

OBJECTIVE: To identify the specific nature of the neurocognitive impairments of eosinophilia-myalgia syndrome (EMS) in an unselected population, and to present longitudinal patterns. METHODS: A consecutive sample of 23 patients with EMS and 18 age and education matched control subjects were assessed on a comprehensive neuropsychological battery. Longitudinal results were gathered from six patients. RESULTS: Neurocognitive impairments were found which represent a subset of deficits reported in previous group and case study reports. Deficits were limited to complex visual memory, conceptual set shifting, and attention, which suggest a selective dysexecutive syndrome. The motor slowing and verbal memory deficits previously reported were not found. Although depression, fatigue, sleep deprivation, and pain were significant symptoms, they were unassociated with deficits with the exception of an association of depression with one deficit. There was no pattern of overall decline over time in a subset of the group, although considerable heterogeneity in the longitudinal patterns of neurocognitive tests was found. Abnormalities of white matter appeared in the MRI of eight of 12 patients. CONCLUSIONS: The neurocognitive and neuroimaging findings contribute to the evidence which indicates that the neural substrate of EMS is white matter damage.

Adult↗
PubMed2003

Clinical application of neuroimaging in epilepsy.

OBJECTIVE: To evaluate the use of neuroimaging in clinical practice and to assess the prevalence of detected structural abnormalities in epilepsy patients in a clinical set up. METHODS: 919 outpatients were identified and the scan results reviewed. A total of 677 patients had chronic active epilepsy (88 had idiopathic generalised epilepsy (IGE), 588 had localisation related epilepsy, one had symptomatic generalised epilepsy), 57 had a single epileptic seizure, 46 were in remission, and 139 had non-epileptic attacks. RESULTS: 391 patients had no scan (53 patients in this group had IGE, 182 had localisation related epilepsy, one had generalised symptomatic epilepsy, 18 had single epileptic attacks, 21 were in remission, 116 had non-epileptic attacks). Altogether 528 patients had a scan, the results were not available in 33, 163 had x ray computed tomography (CT) only, 178 had standard magnetic resonance imaging (MRI) (slice thickness 5 mm), and 154 had high resolution MRI (including a T1 weighted sequence with 1.5 mm thick slices). Some 252 of 495 scans (51%) were abnormal. Abnormalities were hippocampal sclerosis (n=128), atrophy or non-specific white matter lesions (n=35), vascular abnormalities (n=27), tumours (n=25), brain damage (n=24), malformations of cortical development (n=13). Excluding atrophy and non-specific white matter lesions the prevalence of detected abnormalities was 54% in localisation related epilepsy, 18% in single seizure patients, 16% in epilepsy in remission, and 0% in IGE and non-epileptic attacks. CONCLUSIONS: Abnormalities were detected in more than half of all patients with localisation related epilepsy, and in about one in five patients with single seizures or epilepsy in remission. Many patients had no scan or only CT or standard MRI. The true prevalence of structural abnormalities may be have been higher. Scanning did not add any information in patients with IGE or non-epileptic attacks.

Adolescent↗
PubMed2004

Understanding other minds: linking developmental psychology and functional neuroimaging.

Evidence from developmental psychology suggests that understanding other minds constitutes a special domain of cognition with at least two components: an early-developing system for reasoning about goals, perceptions, and emotions, and a later-developing system for representing the contents of beliefs. Neuroimaging reinforces and elaborates upon this view by providing evidence that (a) domain-specific brain regions exist for representing belief contents, (b) these regions are apparently distinct from other regions engaged in reasoning about goals and actions (suggesting that the two developmental stages reflect the emergence of two distinct systems, rather than the elaboration of a single system), and (c) these regions are distinct from brain regions engaged in inhibitory control and in syntactic processing. The clear neural distinction between these processes is evidence that belief attribution is not dependent on either inhibitory control or syntax, but is subserved by a specialized neural system for theory of mind.

Brain↗
PubMed1993

Neuroimaging of juvenile pilocytic astrocytomas: an enigma.

PURPOSE: To present the imaging, metabolic, and clinical data obtained in five patients with juvenile pilocytic astrocytomas (JPAs) and discuss the paradoxical neuroimaging findings. MATERIALS AND METHODS: Five patients with JPAs who had undergone structural imaging and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) were studied. Normalized glucose utilization rates (GURs) in the tumor were compared with GURs in histopathologically verified low-grade astrocytomas and high-grade tumors. RESULTS: All JPAs enhanced markedly after administration of contrast medium. Their glucose metabolism was significantly (P < .001) higher than that of low-grade astrocytomas and was similar to that of anaplastic astrocytomas. All patients with JPAs were in stable condition and showed no evidence of disease progression despite contrast enhancement and high tumoral glucose metabolism. CONCLUSION: The paradoxical FDG PET findings and enhancement at structural imaging might reflect the unusual vascularity of pilocytic tumors, and the increased GUR might be related to expression of the glucose transporter.

Adolescent↗
PubMed1997

Who performs neuroimaging? Results from the 1993 National Medicare Database.

PURPOSE: To determine the level of participation of nonradiologists in computed tomography (CT) and magnetic resonance (MR) imaging of the brain, head and neck, and spine at hospitals and at private offices and imaging centers in the United States. MATERIALS AND METHODS: The 1993 Part B Medicare Annual Database was used to determine the number of procedures performed by radiologists and nonradiologists at hospitals and at private offices or imaging centers. The fourth edition of the Physicians' Current Procedural Terminology was used to classify procedures. RESULTS: Of the 3,883,391 neurologic CT and MR imaging studies billed to Medicare in 1993, 3,148,088 (81%) were obtained in a hospital setting; only 58,005 (2%) of these studies were interpreted by nonradiologists. Of the 735,303 imaging studies (19%) obtained at a private office or imaging center, only 63,115 (9%) studies were interpreted by nonradiologists. Overall, nonradiologists performed only 121,120 (3%) of the neuroimaging examinations billed to Medicare nationwide in 1993. CONCLUSION: The level of participation of nonradiologists in the interpretation of results from neurologic CT and MR imaging billed to Medicare is minimal.

Central Nervous System Diseases↗
PubMed1999

Cree leukoencephalopathy: neuroimaging findings.

PURPOSE: To describe the computed tomographic (CT) and magnetic resonance (MR) imaging findings in Cree leukoencephalopathy. MATERIALS AND METHODS: The authors retrospectively reviewed the medical records and neuroimaging studies in 12 infants with Cree leukoencephalopathy (CT in 12 infants, MR in six). The diagnosis was established clinically in six patients and at autopsy in the other six. RESULTS: At CT, extensive, diffuse, and symmetric hypoattenuation was seen in the cerebral and cerebellar white matter in all 12 patients. Hypoattenuation was also seen in the corpus callosum in 11 (92%), internal capsule in 10 (83%), globus pallidus in nine (75%), brainstem in nine (75%), and thalamus in four (33%). The caudate nucleus and putamen were spared. On T2-weighted MR images in six patients, the cerebral and cerebellar white matter, including the subcortical arcuate fibers, was hyperintense as were the internal capsule, corpus callosum, corticospinal tracts, and globus pallidus. The thalamus was affected in four (67%) patients, pons in five (83%), and medulla in four (33%). The caudate nucleus and putamen were not affected. CONCLUSION: Cree leukoencephalopathy causes striking symmetric and diffuse involvement of the cerebral and cerebellar white matter and brainstem with sparing of the caudate nucleus and putamen.

Encephalitis↗
PubMedDate not supplied

Lymphomatosis cerebri presenting as a rapidly progressive dementia: clinical, neuroimaging and pathologic findings.

Primary central nervous system lymphoma (PCNSL) usually presents with clinical and neuroimaging findings consistent with single or multiple intracranial mass lesions. On cranial magnetic resonance imaging (MRI), such lesions are nearly always contrast enhancing, reflecting disruption of the blood-brain barrier at the site of tumor nodules. We describe 2 cases from the UCLA Medical Center who developed a rapidly progressive dementia due to extensive gray and white matter cerebral lesions involving much of the brain. In the patient who came to autopsy, widely infiltrating, focally necrotic B-cell plasmacytoid lymphoma was noted throughout the cerebral neuraxis. MRI findings in case 2 were consistent with diffuse lymphomatous brain infiltration without mass lesions, which was biopsy proven. We conclude that PCNSL may occur in a diffusely infiltrating form which may occur without MRI evidence of mass lesions or blood-brain barrier compromise. We refer to this entity as 'lymphomatosis cerebri' and add it to the differential diagnosis of a rapidly progressive dementia.

Adult↗
PubMed1998

Neuroimaging and the trimodal brain: applications for developmental communication neuroscience.

New details generated by neuroimaging and other methods for studying the neural correlates of behavior have led to the formulation of a new model of brain organization, the Trimodal Brain. The model incorporates current biochemical; anatomical, and physiological concepts of prenatal brain growth and combines them with findings on right/left functional asymmetries. It provides a means of relating a wide range of human behaviors and clinical states according to a common base of neural organization, and stresses the utility of an organizational rather than a lesion model for understanding developmental communication disorders.

Adolescent↗
PubMed2005

Clinical and neuroimaging correlates of mild cognitive impairment in a middle-aged community sample: the personality and total health through life 60+ study.

This cross-sectional study aimed at determining the clinical and structural brain magnetic resonance imaging correlates of mild cognitive impairment (MCI). The data presented here are from the first wave of the longitudinal Personality and Total Health through Life 60+ project. 2,551 community-dwelling individuals in the age range of 60-64 years were recruited randomly through the electoral roll. They were screened using Mini-Mental State Examination and a short cognitive battery. Those who screened positive underwent detailed medical and neuropsychological assessments. Of the 224 subjects who screened positive, 117 underwent a detailed assessment. Twenty-nine subjects fulfilled the Mayo Clinic criteria for MCI. Magnetic resonance imaging scans were analyzed for 26 subjects with MCI as well as normal controls. Subjects were clinically evaluated for depressive symptoms and major and minor depression syndromes. Logistic regression analysis was performed predicting MCI from anterior and mid-ventricular brain ratios, cortical atrophy measures, hippocampal volumes, volumes of amygdala and white matter hyperintensities after adjusting for age, gender, years of education, depression and physical disability. None of the neuroanatomical substrates appeared as predictors of MCI. The only predictors were higher depression scores and fewer years of education. Structural neuroimaging may not have an added advantage in the detection of MCI in middle-aged community-dwelling subjects. It may be that this age group is too young for such brain changes to be identified.

Amygdala↗
PubMed2006

A probabilistic functional atlas of the VIM nucleus constructed from pre-, intra- and postoperative electrophysiological and neuroimaging data acquired during the surgical treatment of Parkinson's disease patients.

We have previously introduced a concept of a probabilistic functional atlas (PFA) to overcome limitations of the current electronic stereotactic brain atlases: anatomical nature, spatial sparseness, inconsistency and lack of population information. The PFA for the STN has already been developed. This work addresses construction of the PFA for the ventrointermediate nucleus (PFA-VIM). The PFA-VIM is constructed from pre-, intra- and postoperative electrophysiological and neuroimaging data acquired during the surgical treatment of Parkinson's disease patients. The data contain the positions of the chronically implanted electrodes and their best contacts. For each patient, the intercommissural distance, height of the thalamus and width of the third ventricle were measured. An algorithm was developed to convert these data into the PFA-VIM, and to present them on axial, coronal and sagittal planes and in 3-D. The PFA-VIM gives a spatial distribution of the best contacts, and its probability is proportional to best contact concentration in a given location. The region with the highest probability corresponds to the best target. The PFA-VIM is calculated with 0.25-mm3 resolution from 107 best contacts in two situations: with and without lateral compensation against the width of the third ventricle. For the PFA-VIM compensated laterally, the anterior, lateral and dorsal coordinates of the mean value are (in mm) 6.24, 13.83, 1.68 for the left VIM and 6.54, -13.84, 2.10 for the right VIM. The coordinates of the mean value of the highest probability region along with the highest number of the best contacts (P) are: 6.25, 14.25, 1.75, P = 16, for the left VIM, and 6.0, -14.0, 1.00, P = 18, for the right VIM. The coordinate system origin is at the posterior commissure. For the PFA-VIM not compensated laterally, the coordinates of the mean value are 6.24, 13.99, 1.68 for the left VIM and 6.53, -14.13, 2.10 for the right VIM. The coordinates of the mean value of the highest probability region along with the highest number of the best contacts are 5.58, 13.67, 1.33, P = 14, for the left VIM, and 6.36, -14.03, 1.11, P = 17, for the right VIM. The PFA-VIM atlas overcomes several limitations of the current anatomical atlases and can improve targeting of thalamotomies and thalamic stimulations. It is dynamic and can easily be extended with new cases.

Algorithms↗
PubMed1993

Registration of EEG electrodes with three-dimensional neuroimaging using a frameless, armless stereotactic wand.

A technique of image and electrode registration has been developed that allows electroencephalogram electrode location to be merged with 2-D or 3-D MRI or CT. An armless, frameless stereotactic localization system that may be used in or out of the operating room is used to generate spatial data for surface and accessible intracranial electrodes. Acquisition of electrode position data may be obtained before or after neuroimaging and the locations of additional electrodes added at any time. The methodology of this system and representative cases with MRI imaging are presented.

Adult↗
PubMedDate not supplied

Dementia of the frontal lobe type: report of the neuroimaging and neuropsychological results of a case study.

We report the behavioural abnormalities, neuroimaging, and neuropsychological results of a 62-year-old patient, i.p., who shows a clinical profile that fulfils all characteristics of dementia of frontal lobe type. The patient has been followed up over 5 years with psychometric testing. Comparing her cognitive profiles across examinations, her performance was substantially unchanged apart from behavioural disturbances and performance on frontal tasks which showed a progressive worsening. MRI finding evidenced marked ventricular enlargement, prevalent frontal atrophy and hypertrophy of the genus of corpus callosum. SPECT investigation showed a considerable reduction of cerebral blood flow in the mesial parts of the frontal lobes, in the lateral surface of the right fronto-parietal lobe, and hypo-perfusion in the right thalamic area. The results are discussed with reference to the features (clinical and neuropsychological) which distinguish different profiles of dementia.

Behavior↗
PubMed2004

Neuroimaging with calibrated FMRI.

The conventional functional MRI (fMRI) map offers information indirectly about localized changes in neuronal activity because it reflects changes in blood oxygenation, not actual neuronal activity. To provide a neurophysiological basis of fMRI, researchers have used electrophysiology to show correlations of fMRI and electric signals. However, quantitative interpretation of the degree to which neuronal activity has changed still cannot be made from conventional fMRI data. The fMRI signal has 2 parts: one describes the correlation between oxidative metabolism (cerebral metabolic rate of oxygen [CMRO2]) and cerebral blood flow (CBF), which supports the bioelectric work to sustain neuronal excitability; the other is the requisite dilation of blood vessels (cerebral blood volume [CBV]), which is the mechanical response involved in removal of waste while providing nutrients. Since changes in energy metabolism are related to bioelectric work, we tested whether spiking frequency of a neuronal ensemble (nu) is reflected by local energy metabolism (CMRO2) in rat brain. We used extracellular recordings to measure Deltanu/nu and calibrated fMRI (ie, using fMRI signal, CBF, and CBV maps) to measure DeltaCMRO2/CMRO2 during sensory stimulation. We found that DeltaCMRO2/CMRO2 is approximately Deltanu/nu, which suggests efficient energy use during brain work. Thus, calibrated fMRI provides data on where and by how much the neuronal activity has changed. Possibilities of utilizing calibrated fMRI as a neuroimaging method are discussed.

Animals↗
PubMed1993

Cerebellar infarction. Clinical and neuroimaging analysis in 293 patients. The Tohoku Cerebellar Infarction Study Group.

BACKGROUND AND PURPOSE: We performed this multicenter study to explore the full spectrum of the clinical characteristics and neuroimaging findings of cerebellar infarction, including patients with mild to severe illnesses. METHODS: We studied 293 consecutive patients with cerebellar infarction diagnosed by computed tomography and/or magnetic resonance imaging who were admitted to 36 hospitals during 5 years. RESULTS: Cerebellar infarcts constituted 2.3% of the total patients with acute brain infarction. The backgrounds and risk factors were similar to those in patients with infarctions of the cerebral hemispheres. At least 24% were embolic, and the diagnosis of embolism could not be ruled out in 27%. Infarcts involving the superior cerebellar artery (SCA) region (52%) and the posterior inferior cerebellar artery (PICA) region (49%) were far more frequent than those involving the anterior inferior cerebellar artery (AICA) region (20%). Patients with SCA infarcts exhibited obtunded consciousness and ataxia more frequently than those with PICA infarcts (P < .05). Infarcts in the PICA regions were associated with abnormalities of the PICA (64%) or the vertebral arteries (57%), whereas infarcts in the SCA and AICA regions were associated with abnormalities in the SCA or AICA, respectively, in approximately 30% of patients, in the basilar artery in approximately 16%, and in the vertebral artery in more than 60% of patients. Outcomes were poorer with SCA infarcts than with AICA and PICA infarcts. CONCLUSIONS: These data indicate similar frequencies of SCA and PICA infarcts and illustrate the difference in clinical presentation and outcomes between SCA and PICA infarcts. They also indicate that not only in situ thrombosis but also cardiogenic or artery-to-artery embolism and the insufficiency of collateral circulation play important roles in the pathogenesis of cerebellar infarction.

Aged↗
PubMed2003

Neuroimaging studies of word and pseudoword reading: consistencies, inconsistencies, and limitations.

Several functional neuroimaging studies have compared words and pseudowords to test different cognitive models of reading. There are difficulties with this approach, however, because cognitive models do not make clear-cut predictions at the neural level. Therefore, results can only be interpreted on the basis of prior knowledge of cognitive anatomy. Furthermore, studies comparing words and pseudowords have produced inconsistent results. The inconsistencies could reflect false-positive results due to the low statistical thresholds applied or confounds from nonlexical aspects of the stimuli. Alternatively, they may reflect true effects that are inconsistent across subjects; dependent on experimental parameters such as stimulus rate or duration; or not replicated across studies because of insufficient statistical power. In this fMRI study, we investigate consistent and inconsistent differences between word and pseudoword reading in 20 subjects, and distinguish between effects associated with increases and decreases in activity relative to fixation. In addition, the interaction of word type with stimulus duration is explored. We find that words and pseudowords activate the same set of regions relative to fixation, and within this system, there is greater activation for pseudowords than words in the left frontal operculum, left posterior inferior temporal gyrus, and the right cerebellum. The only effects of words relative to pseudowords consistent over subjects are due to decreases in activity for pseudowords relative to fixation; and there are no significant interactions between word type and stimulus duration. Finally, we observe inconsistent but highly significant effects of word type at the individual subject level. These results (i) illustrate that pseudowords place increased demands on areas that have previously been linked to lexical retrieval, and (ii) highlight the importance of including one or more baselines to qualify word type effects. Furthermore, (iii) they suggest that inconsistencies observed in the previous literature may result from effects arising from a small number of subjects only.

Adult↗
PubMed2003

A parametric manipulation of factors affecting task-induced deactivation in functional neuroimaging.

Task-induced deactivation (TID) refers to a regional decrease in blood flow during an active task relative to a "resting" or "passive" baseline. We tested the hypothesis that TID results from a reallocation of processing resources by parametrically manipulating task difficulty within three factors: target discriminability, stimulus presentation rate, and short-term memory load. Subjects performed an auditory target detection task during functional magnetic resonance imaging (fMRI), responding to a single target tone or, in the short-term memory load conditions, to target sequences. Seven task conditions (a common version and two additional levels for each of the three factors) were each alternated with "rest" in a block design. Analysis of covariance identified brain regions in which TID occurred. Analyses of variance identified seven regions (left anterior cingulate/superior frontal gyrus, left middle frontal gyrus, right anterior cingulate gyrus, left and right posterior cingulate gyrus, left posterior parieto-occipital cortex, and right precuneus) in which TID magnitude varied across task levels within a factor. Follow-up tests indicated that for each of the three factors, TID magnitude increased with task difficulty. These results suggest that TID represents reallocation of processing resources from areas in which TID occurs to areas involved in task performance. Short-term memory load and stimulus rate also predict suppression of spontaneous thought, and many of the brain areas showing TID have been linked with semantic processing, supporting claims that TID may be due in part to suspension of spontaneous semantic processes that occur during "rest" (Binder et al., 1999). The concept that the typical "resting state" is actually a condition characterized by rich cognitive activity has important implications for the design and analysis of neuroimaging studies.

Acoustic Stimulation↗