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PubMedDate not supplied

[Schizophrenia: a brain disease. I. Structural neuroimaging].

Structural neuroimaging has provided some of the most robust evidence of biologic abnormalities in the brains of patients with schizophrenia. Limbic and ventricular abnormalities now have been replicated in many studies. Despite this progress, more than two decades of research in structural neuroimaging have failed to identify the pathophysiology underlying schizophrenia. In this article we review the principal literature on structural neuroimaging, identify methodologic problems and critically evaluate the significance of the results obtained to date. As image resolution and processing ability improves and this line of research is combined with others, we can expect significant advances in our knowledge of the pathophysiology and the importance of brain abnormalities in the life of patients with schizophrenia.

Brain↗

PubMed2000

[Central nervous system tuberculosis with and without HIV infection--clinical, neuroimaging, and neuropathological study].

Clinical data, neuroimaging, and neuropathology of 17 patients with central nervous system tuberculosis were reported. Of this population, 12 were men, 5, women; ages ranged from 23 to 75 years (mean, 46.9). There were three HIV positive patients among them. More than a half of patients had disturbance of consciousness as initial symptom. Neurological signs were variable such as visual acuity loss, hemiparesis, paraparesis, cerebellar ataxia, and tremor, though disturbance of consciousness was the most frequent (36%). Neuroimaging (X-ray CT and MRI) revealed meningeal enhancement (53%), tuberculoma (50%), hydrocephalus, infarction or bleeding and spinal cord tuberculoma. There were three patients who showed paradoxical progression. Eleven patients were performed CSF examination, all of them revealed increased cell count (mean, 206 counts/mm3) and protein (mean, 225 mg/dl), but only 4 patients were positive on bacteriological examination including PCR. Seven patients died and 5 patients were performed autopsy. Neuropathologically, all patients showed a stage of meningitis prominent on basal brain (basal cistern and/or Sylvian fissure). Cell infiltrations including lymphocyte, monocyte, and eosinocyte were most severe around blood vessels, and observed in all cases except one which showed only fibroblast and collagen fibers indicating healed stage. In some cases, there existed epithelioid cells and Langhans giant cells, and in some cases, fibrin exudate. There were three cases having tuberculoma, one HIV case and two non-HIV cases. Center of tuberculoma in non-HIV case was formed by caseous necrosis, and tuberculoma was surrounded by granuloma constituted by epithelioid cells and Langhans giant cells with lymphocyte cell infiltration and proliferation of blood vessels. In contrast, tuberculoma of HIV case did not include granuloma, and was formed with small cells with large nucleus which surrounded arteries. Our studies, as other studies, failed to show any differences between HIV and non-HIV patients clinically, as well as on neuroimaging study. But neuropathological study suggests that mechanism of tuberculoma formation may be different between in HIV positive patients and in non-HIV patients.

Adult↗

PubMed2001

Thrombotic thrombocytopenic purpura: prospective neurologic, neuroimaging and neurophysiologic evaluation.

BACKGROUND AND OBJECTIVES: Neurologic symptoms are present in 60% of patients with thrombotic thrombocytopenic purpura (TTP) on initial examination and ultimately develop in about 90% of cases during the course of the disease. Despite central nervous system involvement being frequent, abnormalities in the brain of patients with TTP are infrequent on neuroimaging (CT/MRI) and neurophysiologic (EEG) evaluation, often reversible and mainly limited to symptomatic stages of the disease. The aim of our study was to establish the value of a complete neurologic screening as part of the work up of TTP. DESIGN AND METHODS: We prospectively evaluated 16 TTP patients, performing serial neurologic, neuroimaging and EEG examinations, independently of the presence of an objective central nervous system involvement. RESULTS: Our study shows that a complete neurologic evaluation is of modest help in improving the diagnosis of TTP, but may be useful for the neurologic management. INTERPRETATION AND CONCLUSIONS: Accurate neuroimaging and, especially, EEG evaluation and monitoring allowed us to identify patients who could benefit from anticonvulsive therapy, avoiding the unnecessary administration of the latter. The prognostic utility of complete neurologic screening in TTP remains to be conclusively demonstrated in larger prospective neurologic studies.

Adolescent↗

PubMed2001

Neural correlates of emotions in psychiatric patients in the light of functional neuroimaging findings.

The question whether there exists "the emotional brain" still remains open. The greatest scientific challenge at the threshold of 2000 is to make "a map of brain emotions" with a detailed topography for each "basic emotion". The investigations, with the use of the most advanced neuroimaging techniques: positron emission tomography(PET), functional magnetic resonance (fMRI) and SPECT (single photon emission computed tomography), aimed at obtaining more precise location data on the system regulating the effect in normal and in pathology. In recent years, with the use of neuroimaging techniques, an important role of posterior temporal cortex, orbital-frontal cortex, amygdaloid nucleus and insula in the regulation of emotional behaviour has been indicated. The present study is an attempt at: 1) systemizing the research experiments serving the investigation of emotions with the use of neuroimaging techniques, 2) systemizing the latest results of investigations aimed at either search of the "emotional brain", or neural correlates of emotions responsible for the regulation of emotional behaviour in anxiety and affective disorders as well as in schizophrenic disorders.

Anxiety Disorders↗

PubMed2002

[Evaluation of dreams by the neuropsychological approach. Utility in the characterization of cerebral correlates in oneiric activity by functional neuroimaging].

Recent neuroimaging studies show that human REM sleep is characterized by a specific pattern of regional brain activity. While being usually interpreted in relation to physiological and cellular mechanisms, the regionally-specific distribution of brain activity during REM sleep may also be linked to specific dream features. Remarkably, several bizarre features of dreams present similarities with wellknown neuropsychological syndromes after brain damage, such as delusional misidentifications for faces and places. We propose that neuropsychological analysis of dream content might offer new ways of interpreting neuroimaging maps, as well as specific predictions for future neuroimaging studies.

Brain Injuries↗

PubMed2002

[Neuroimaging features in progressive supranuclear palsy and corticobasal degeneration].

Progressive supranuclear palsy (PSP) and cortocobasal degeneration (CBD) are often clinically confused with each other. In this paper, based our previous and on-going morphological and functional neuroimaging studies, the features characteristic of the two diseases are discussed. In PSP patients, the atrophic and metabolic changes are dominant in the frontal lobes, basal ganglia, and midbrain, while in CBD patients, the changes are dominant in the parietal lobe. There is little overlap of topographical distribution of atrophy and functional changes between PSP and CBD, despite the considerable similarity of symptoms of the two disorders. The clear distinction between the two diseases may be in part caused by the criteria-based subject selection process; based on stringent clinical diagnostic criteria for each disorder, which have a high specificity and a low sensitivity, only patients that are typical of each disease are compared. Nevertheless, these neuroimaging features appear to reflect different clinical and pathologic phenotypes between the two diseases. These findings suggest that neuroimagings facilitate the differential diagnosis between patients with PSP and those with CBD.

Humans↗

PubMed2004

Neuroimaging of the complications of epilepsy surgery.

BACKGROUND AND PURPOSE: Stroke-like symptoms can be associated with the invasive evaluation and surgical resection of epileptic foci in patients with intractable epilepsy. Neurological deficits following surgical procedures for epilepsy are not uncommon, but most are relatively minor and transient. The authors investigated the neuroimaging patterns of cerebral tissue insults in patients suffering neurological deficits directly related to procedures performed to evaluate and treat intractable epilepsy. They attempted to discern potential secondary vascular insults from the not unexpected tissue loss that can be associated with various epilepsy procedures. METHODS: The authors prospectively assessed 7 consecutive patients who underwent either the invasive electrocortigraphic monitoring or surgical resection of epileptic foci. All had some degree of neurological deficit postoperatively. The authors evaluated for tissue injury type with postoperative computed tomography and magnetic resonance brain imaging. They also review pertinent medical literature addressing potential complications of epilepsy surgery. RESULTS: Three patients had primarily ischemic tissue injuries, 2 had tissue loss with minor bleeding, and 1 transient deficit appeared to reflect the amount of tissue removed. Another patient had choreiform movements and gait ataxia 1 week after the procedure, but no follow-up neuroimaging was available. The primary ischemic insults appeared to be related to vascular traction or compression or possibly vasospasm. The tissue loss/hemorrhagic insults were presumably related to tissue loss, with seepage of blood or bleeding from a resected cavernous hemangioma. No patients died, but 1 was left with a persistent, moderately severe neurological deficit. CONCLUSIONS: It is important to distinguish the not unexpected neurological deficits associated with inadvertent trauma to normal brain tissue during procedures associated with epilepsy surgery from vascular insults. Postoperative neuroimaging can be useful in this endeavor.

Adolescent↗

PubMedDate not supplied

[Neuroimaging in Alzheimer's disease: an overview].

INTRODUCTION: Clinically, computerized tomography scanning and magnetic resonance imaging (MRI) are the neuroimaging techniques most frequently used in the work up of progressive cognitive impairment, in order to rule out tumors or other treatable etiologies. However, as we move closer to having more effective treatments for Alzheimer's disease (AD), we experience a greater need to use markers of early brain injury. Among them is neuroimaging. In this review we give some examples of the role of MRI and of functional MRI (fMRI) as markers of early brain changes. DEVELOPMENT: Regional metabolism, studied with positron emission tomography (PET) can also be used advantageously to depict early cortical changes in mild cognitive impairment (MCI) and even presymptomatic AD. SPECT, less expensive than PET, has a lower sensitivity, but has been extensively studied and using quantification methods can help even in MCI. Newer PET markers allow for the evaluation of activated microglia in vivo, as well as for the study of amyloid deposition in the brain and the activity of enzymes such as acetyl-cholinesterase. CONCLUSION: Future refinements in the neuroimaging techniques seem likely to help in the early diagnosis, evaluation of potential treatments and clarification of pathogenetic mechanisms in AD.

Acetylcholinesterase↗

PubMed2004

[Clinical and neuroimage characteristics of primary central nervous system lymphoma].

OBJECTIVE: To analyze the clinical and neuroimage characteristics of primary central nervous system lymphoma and explore the methods of treatment. METHODS: The clinical data of 28 cases of primary central nervous system lymphoma were analyzed retrospectively. RESULTS: All the 28 patients with lyphoma were proved by craniotomy and pathologic study. The survival periods were 5 days to 40 months after the craniotomy. Eighteen patients received radiotherapy after the operation. Sixteen recurrent cases were proved by neuroimage and the minimum recurrent time was the 29th day after the operation. CONCLUSION: The duration of primary lymphoma in the central nervous system is short and the clinical symptom is serious. The neuroimage of primary lymphoma in the central nervous system has some characteristic changes. The recurrence may occur over a brief time after the operation even though the tumor has been totally removed under the microscope. The majority of lymphomas are sensitive to radiotherapy.

Adolescent↗

PubMed2004

Functional neuroimaging in mental disorders.

Recent advances in functional neuroimaging allow us to map neural activity in the living human brain with precise spatial and temporal resolution and provide an unprecedented opportunity to examine the neurocognitive components of mental disorders. In this article we aim to summarize the main functional neuroimaging findings in the major psychiatric disorders and the different methodological approaches that have been used to study them. We will discuss studies of the resting state and of activation during the performance of cognitive tasks, and studies focused on specific psychiatric symptoms. We will also review work on functional connectivity, discuss future directions in the field and consider how functional neuroimaging may contribute to clinical practice.

Journal Article↗

PubMed2006

Neuroimaging in children with first afebrile seizures: to order or not to order?

Seizures are common in children and 5% of all medical attendances to accident and emergency departments are related to seizures. The role of emergent neuroimaging for those children with first afebrile seizure is, however, not well-defined. We reviewed medical charts of 125 children who were admitted with a new-onset afebrile seizure to the Pediatric Ward of Rasool Akram Hospital and underwent CT scan or MRI of the brain. Neuroimaging was performed for 95% (119/125) of these children over the first few hours of their arrival to the Emergency Department. In 90% (107/119) of them, the result was normal. There was a significant relationship between abnormal neuroimaging and focal seizure (P < 0.001), and with age under 2 years (P < 0.002). Therefore, it is recommended that CT scan or MRI to be performed in children with first afebrile seizure who present with focal seizures, abnormal neurologic findings, or age under 2 years.

Adolescent↗

PubMed2006

Federating distributed and heterogeneous information sources in neuroimaging: the NeuroBase Project.

The NeuroBase project aims at studying the requirements for federating, through the Internet, information sources in neuroimaging. These sources are distributed in different experimental sites, hospitals or research centers in cognitive neurosciences, and contain heterogeneous data and image processing programs. More precisely, this project consists in creating of a shared ontology, suitable for supporting various neuroimaging applications, and a computer architecture for accessing and sharing relevant distributed information. We briefly describe the semantic model and report in more details the architecture we chose, based on a media-tor/wrapper approach. To give a flavor of the future deployment of our architecture, we de-scribe a demonstrator that implements the comparison of distributed image processing tools applied to distributed neuroimaging data.

Databases as Topic↗

PubMed1984

Neuroimaging in brain swelling.

Modern neuroimaging techniques have added to the understanding of brain edema and its earlier diagnosis. It is now possible to quickly know whether a lesion is focal with associated pressure effects or whether the symptoms are due to a diffuse process whose treatment may be different. The various herniation syndromes can be appreciated on the CT without risk to the patient. The neuropathologic proof of earlier pathophysiologic theories of three types of edema (vasogenic, cytotoxic, and interstitial) caused by various diseases need no longer wait for the autopsy specimen; it is strongly suggested by modern neuroimaging techniques. Some disease entities (meningitis, trauma, ischemic infarction) are characterized by several types of edema, depending on when the patient is examined. Swelling of the brain is an important topic to study not only because it is common, but also because it may be fatal. Neuroimaging in brain swelling has led to new knowledge regarding this important subject. This review is primarily that of the computerized tomogram in diagnosing both focal and diffuse swelling of the brain and some basic understanding pathophysiologically that would allow one to explain the image obtained. Because edema is primarily water, it seems likely that magnetic resonance imaging will shed even further light on this intriguing subject.

Blood-Brain Barrier↗

PubMedDate not supplied

Neuroimaging in the high-risk infant: relationship to outcome.

Early brain development involves a genetically programmed, spatially organized, and temporally orchestrated cascade of events. Deleterious prenatal perinatal events may disrupt this sequence and lead to a spectrum of developmental impairments including cerebral palsy and mental retardation. Before the advent of cranial ultrasonography, cranial tomography, and magnetic resonance imaging, neuropathologic correlations were usually established post mortem. These neuroimaging modalities have improved the identification of brain lesions in surviving high-risk preterm and term infants. This has permitted inferences as to timing and pathophysiologic condition of the insult(s) and has facilitated correlations with clinical examination. In very low birth weight infants ultrasonographic abnormalities reflecting white matter damage have the strongest correlations with cerebral palsy: (1) persistent ventricular enlargement or persistent parenchymal echodensities carry a 50% risk for cerebral palsy, and (2) large bilateral cysts in periventricular white matter carry a risk approaching 75% to 95%. In term infants neuroimaging studies show selective vulnerability in cerebral cortex and basal ganglia. This article reviews relationships between neuroimaging findings and outcome to help clinicians interpret the results and to gain an understanding of risk in their patients.

Brain↗

PubMed1998

Neuroimaging for diagnosis of dementia.

Although many clinicians consider neuroimaging studies as optional for the differential diagnosis of dementia, clinical experience suggests that they can improve diagnostic accuracy. Data are limited, however, on sensitivity, specificity, and cost-effectiveness of various neuroimaging techniques. The author reviews advantages and disadvantages of neuroimaging techniques for the differential diagnosis of dementia and describes strategies used for early detection of Alzheimer's disease, including combining positron emission tomography scanning with genetic risk assessment. Such approaches could provide a means for in vivo therapeutic monitoring of brain function during experimental antidementia treatment trials.

Aged↗

PubMed1998

[The value of structural neuroimaging in the selection of patients for epileptic surgery].

UNLABELLED: The aim of this study was to investigate the value of structural neuroimaging with MRI in the selection of patients for epilepsy surgery. We sought to determine whether MRI influenced decision concerning resective surgery and whether MRI provided much more useful information than enhanced CT. MATERIALS AND METHODS: Neuroimaging studies, MRI and CT, of 300 patients; 265 with partial and 35 with primary generalized seizures, evaluated for surgical treatment of epilepsy were analysed. The MRIs and CTs were interpreted using visual diagnostic criteria and findings were correlated with the EEG changes and clinical semiology. RESULTS: MRIs identified structural lesions in 142, CTs in 96 of all patients. The clinical semiology (partial seizures), MRI, CT and EEG focal findings were concordant in 72 cases. The group of 34 patients had resective surgery. The 7 patients were also operated with MRI and CT focal abnormalities discordant with EEG changes. Also one patient with primary generalized epilepsy and temporal lobe lesion (glioma) had resective surgery. MRI studies revealed structural lesions in 48 patients with normal CT studies. The 43 patients with partial epilepsy had normal CTs and lesions in MRIs; the 34 cases revealed correlation with the EEG findings in 29 temporal and 5 extratemporal regions. Surgery were performed in 23 cases. Also one with partial seizures and MRI detected hippocampal atrophy was operated, despite of generalized EEG patterns. In contrast CT revealed two patients with normal MRI and focal changes. The patients with partial seizures and only CT abnormalities (focal calcifications) were not operated due to discordant EEG findings. In group of 132 patients with normal neuroimaging studies and EEG identified seizure focus only 27 had anterior temporal lobectomy. CONCLUSION: MRI studies gave additional information in case of 16% patients with intractable epilepsy in comparison with CT findings. Resective epilepsy surgery was almost twice as often performed when MRIs revealed structural abnormality. In operated patients, diagnostic sensitivity of structural MRI, CT and EEG to neurophatology were 70.6%, 46.7 and 92.4% respectively.

Adolescent↗

PubMed1998

Neuroimaging and frontal-subcortical circuitry in obsessive-compulsive disorder.

BACKGROUND: Neuroimaging studies provide strong evidence that the pathophysiology of obsessive-compulsive disorder (OCD) involves abnormal functioning along specific frontal-subcortical brain circuits. METHOD: A literature search was carried out for all brain imaging studies of patients with OCD. We also reviewed the basic science literature on the functional neuroanatomy of cortico-basal ganglia circuits, and integrated this information with neuroimaging data in OCD to formulate a theoretical model of brain mediation of OCD symptoms and response to treatment. RESULTS: At least a subgroup of patients with OCD may have abnormal basal ganglia development. Functional neuroimaging studies indicate that OCD symptoms are associated with increased activity in orbitofrontal cortex, caudate nucleus, thalamus and anterior cingulate gyrus. CONCLUSIONS: OCD symptoms are mediated by hyperactivity in orbitofrontal-subcortical circuits, perhaps due to an imbalance of tone between direct and indirect striato-pallidal pathways. We present a model which describes how frontal-subcortical brain circuitry may mediate OCD symptomatology, and suggest a hypothesis for how successful treatments may ameliorate symptoms, via their effects on circuit activity.

Brain Diseases↗

PubMed2026

Complexity in disguise: a systematic review of fractal analysis in psychiatric neuroimaging.

OBJECTIVES: Psychiatric diagnosis and fractal studies are complex processes that extend beyond clinical evaluation and require careful methodological considerations in neuroimaging. Over the years, fractals have helped reduce these complexities in research, but they still cannot grant clinical diagnoses. Thus, the main objective was a systematic review exploring the potential applications of fractal analysis in characterizing psychiatric conditions through neuroimaging techniques-including both functional and structural MRI. MATERIALS AND METHODS: A systematic literature review was conducted on PubMed, identifying thirty-nine original studies that met the inclusion criteria. Areas showing statistical significance (p < 0.05) were reported. These studies were categorized according to DSM-V classification and examined for the description of psychiatric conditions through the fractal analysis. RESULTS: The review primarily focuses on young adults with psychiatric conditions compared to control groups. Schizophrenia and Autism Spectrum Disorder are major areas of investigation, and fractal dimension (FD) is the primary analysis method used to reflect brain patterns. Studies that calculated whole-brain FD may have underestimated local abnormalities due to the inclusion of a high percentage of tissue, potentially resulting in overlooked findings. Notably, abnormalities in the frontal cortex represent a common neurobiological feature across several psychiatric conditions. CONCLUSIONS: The findings from this systematic review shed light on the use of fractal analysis to quantify complex brain patterns in both psychiatric patients and healthy individuals. However, it is essential to recognize the need for further research to elucidate a fractal analysis protocol that allows for optimal extraction of psychiatric insights. KEY POINTS: Question Fractal analysis applied to structural and functional MRI help characterize brain alterations across psychiatric conditions. Findings This review shows consistent fractal patterns across multiple psychiatric disorders, especially in frontal regions. Despite heterogeneous methodologies, results highlight shared structural and functional abnormalities. Clinical relevance Fractal analysis may offer complementary characterization of subtle brain organization across psychiatric disorders. Its potential clinical utility-such as improving diagnostic characterization, earlier detection, among others-remains limited by the current absence of a standardized protocol.

Humans↗