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Results for “Neuroimaging”

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PubMed1995

Neonates treated with ECMO: predictive value of early CT and US neuroimaging findings on short-term neurodevelopmental outcome.

PURPOSE: To determine if neuroimaging findings in infants who undergo extracorporeal membrane oxygenation (ECMO) are predictive of developmental outcome. MATERIALS AND METHODS: At 1-2 years of age, 183 ECMO survivors (69 female, 114 male) underwent developmental examination. Neuroimaging studies obtained at time of ECMO were assigned a neuroimaging score. Neuroimaging findings were correlated with developmental outcome. RESULTS: Eighty-five infants had neuroimaging abnormalities. Development was normal in 105 infants, suspect in 37, and delayed in 41. Mean neuroimaging scores were significantly worse in survivors with delayed development (P < or = .0001). The sensitivity and specificity of normal neuroimaging findings in prediction of normal outcome were 65% and 63%, respectively. Survivors with nonhemorrhagic abnormalities had a higher risk of delayed development than did those with isolated hemorrhagic abnormalities (39% vs 21%). CONCLUSION: Although they cannot be used alone to predict outcome, early neuroimaging scores can be used to assign risk categories for developmental outcome.

Brain↗

PubMed2025

Neuroimaging PheWAS and molecular phenotyping implicate PSMC3 in Alzheimer's Disease.

INTRODUCTION: Neuroimaging genetics have advanced Alzheimer's disease (AD) research, yet frameworks mechanistically connecting genes to neurological outcomes via functional genomics are needed to elucidate genetic associations. To address this challenge, we assessed relationships between AD-associated variants and disease via their impact on gene expression and neuroimaging phenotypes. METHODS: We mapped established AD genes to neuroimaging traits using NeuroimaGene atlas and predicted transcript-driven AD neurological features by comparing gene-derived neuroimaging features to clinical neuroimaging data. Genetic correlation and covariance analyses characterized shared genetic architecture between AD endophenotypes and neuroimaging features and identified neuroimaging features associated with dementia family history. RESULTS: Our analyses implicate PSMC3 expression as a strong contributor to AD pathophysiology and indicate AD endophenotypes, including dementia family history, linked to frontal cortex thickness, volume, and cerebrospinal fluid volume changes. DISCUSSION: Our findings prioritize AD genes whose regulation is associated with vulnerable brain regions, offering a potential mechanistic framework for downstream functional validation.

Alzheimer’s Disease↗

PubMed1995

Neuroimaging and cerebrospinal fluid cytology in the diagnosis of leptomeningeal metastasis.

The diagnosis of leptomeningeal metastasis is often difficult and usually requires the demonstration of malignant cells in the cerebrospinal fluid. Neuroimaging, however, may establish or support the diagnosis in some patients. Radiographic abnormalities consistent with or suggestive of leptomeningeal metastasis include leptomeningeal, subependymal, dural, or cranial nerve enhancement; superficial cerebral lesions; and communicating hydrocephalus. We evaluated 137 cancer patients with clinical symptoms suspicious for leptomeningeal metastasis with neuroimaging or cerebrospinal fluid cytology or both. Neuroimaging findings were abnormal in 70 of 128 tested patients; cytology was performed in 58 of these 70 and the results were positive in 37. Conversely, cytological findings were positive in 53 of 115 tested patients; neuroimaging was performed in 49 of these 53 and the findings were abnormal in 37 (26/29 solid tumors and 11/20 hematological tumors). Of the total series of 137 patients, leptomeningeal metastasis was diagnosed in 77; in 24 (31%) the diagnosis was made on the basis of clinical picture and abnormal neuroimaging alone. Neuroimaging is a valuable tool in the investigation of leptomeningeal metastasis in the cancer population, and the presence of typical clinical features together with appropriate neuroimaging abnormalities is adequate to make the diagnosis of leptomeningeal metastasis even if cerebrospinal fluid cytological results are negative.

Adolescent↗

PubMed1998

Neuroimaging studies of word reading.

This review discusses how neuroimaging can contribute to our understanding of a fundamental aspect of skilled reading: the ability to pronounce a visually presented word. One contribution of neuroimaging is that it provides a tool for localizing brain regions that are active during word reading. To assess the extent to which similar results are obtained across studies, a quantitative review of nine neuroimaging investigations of word reading was conducted. Across these studies, the results converge to reveal a set of areas active during word reading, including left-lateralized regions in occipital and occipitotemporal cortex, the left frontal operculum, bilateral regions within the cerebellum, primary motor cortex, and the superior and middle temporal cortex, and medial regions in the supplementary motor area and anterior cingulate. Beyond localization, the challenge is to use neuroimaging as a tool for understanding how reading is accomplished. Central to this challenge will be the integration of neuroimaging results with information from other methodologies. To illustrate this point, this review will highlight the importance of spelling-to-sound consistency in the transformation from orthographic (word form) to phonological (word sound) representations, and then explore results from three neuroimaging studies in which the spelling-to-sound consistency of the stimuli was deliberately varied. Emphasis is placed on the pattern of activation observed within the left frontal cortex, because the results provide an example of the issues and benefits involved in relating neuroimaging results to behavioral results in normal and brain damaged subjects, and to theoretical models of reading.

Brain↗

PubMed2000

The role of routine laboratory studies and neuroimaging in the diagnosis of dementia: a clinicopathological study.

OBJECTIVE: To determine the neuropathological diagnoses of longitudinally followed patients with potentially reversible causes of dementia and to examine the results of the "dementia work-up," especially neuroimaging, by comparison with the pathological diagnosis. DESIGN: A neuropathologic series of 61 consecutive patients, with review of clinical, laboratory, neuroimaging, and pathological results. RESULTS: Of the 61 patients, forty-eight (79%) had a clinical diagnosis of probable or possible Alzheimer's disease (AD). Compared with the pathological diagnosis, the sensitivity and specificity of the clinical diagnosis of AD were 96% and 79%, respectively. Of the 61 patients, 9 had abnormal laboratory tests, the correction of which did not improve the subsequent course. These patients were found to have AD8 and frontotemporal dementia on pathology. In two patients, neuroimaging was helpful in the clinical diagnoses of frontotemporal dementia and progressive supranuclear palsy (PSP). Neuroimaging revealed cerebrovascular disease in 18 patients, only two of whom were suspected clinically. Pathology confirmed AD in 17 and PSP in 1 of these patients. Sensitivity and specificity for the clinical diagnosis of cerebrovascular disease in comparison with pathology were 6% and 98%, respectively. With the added information from neuroimaging, that sensitivity increased to 59% and specificity decreased to 81%. CONCLUSIONS: All cases with abnormal laboratory or neuroimaging results had AD or some other neurodegenerative disease on pathology. The "dementia work-up" did not reveal any reversible causes for dementia in this group of patients. Neuroimaging may have a role, especially in the diagnosis of possible AD with concomitant cerebrovascular disease.

Aged↗

PubMed2002

Value of neuroimaging in the evaluation of neurologically normal children with recurrent headache.

Headache is one of the most frequent physical complaints in children. Although headaches in children are generally benign, neuroimaging studies are frequently performed in clinical practice for the fear of missing a serious underlying disease. Despite this, limited data exist about the utility of neuroimaging in recurrent headache of children with a normal neurologic examination. This prospective study was planned to determine the value of neuroimaging in neurologically normal children with migraine and tension-type headache. Among 95 consecutive patients presenting with headache, 72 patients receiving a diagnosis of migraine or tension-type headache were included in the study. Neuroimaging procedures were performed in 83%. Magnetic resonance imaging (MRI) was abnormal in 11 of 49 cases. Abnormalities consisted of foci of gliosis in four, sinusitis in two, pineal cyst in one, periventricular leukomalacia in one, arachnoid cyst in one, old traumatic changes in one, and cervical syrinx in one. Two of the 11 computed tomographic (CT) scans revealed sinus disease. The percentage of findings causally related to headache was about 10. None of the patients had undergone surgery because of neuroimaging results. In conclusion, the yield of neuroimaging in recurrent headaches of children with a normal neurologic examination is low, and neuroimaging should not be part of a routine initial examination of these patients.

Adolescent↗

PubMed2003

Red flags in patients presenting with headache: clinical indications for neuroimaging.

Headache is a very common patient complaint but secondary causes for headache are unusual. Neuroimaging is both expensive and has a low yield in this group. Most patients with intracranial pathology have clinical features that would raise a "red flag". Appropriate selection of patients with headache for neuroimaging to look for secondary causes is very important. Red flags act as screening tools to help in identifying those patients presenting with headache who would benefit from prompt neuroimaging, and may increase the yield. The aim of this study is to evaluate clinical features in patients with headache using neuroimaging as a screening tool for intracranial pathology. 20 red flags were defined. A retrospective study of 111 patients was performed and the outcomes were divided into positive and negative. Abnormal neuroimaging was present in 39 patients. Results were analysed using the Logistic Regression model. Sensitivity and specificity of red flags were analysed to establish the cut-off point to predict abnormal neuroimaging and a receiver operating characteristic (ROC) curve plotted to show the sensitivity of the diagnostic test. Three red flag features proved to be statistically significant with the p-value of less than 0.05 on both univariate and multivariate analysis. These were: paralysis; papilloedema; and "drowsiness, confusion, memory impairment and loss of consciousness". In addition, if three or more red flags from the list were present, this showed strong indication of abnormal neuroimaging, from cut-off point of ROC curve (area under the curve =0.76).

Adolescent↗

PubMed2006

Does this patient with headache have a migraine or need neuroimaging?

CONTEXT: In assessing the patient with headache, clinicians are often faced with 2 important questions: Is this headache a migraine? Does this patient require neuroimaging? The diagnosis of migraine can direct therapy, and information obtained from the history and physical examination is used by physicians to determine which patients require neuroimaging. OBJECTIVE: To determine the usefulness of the history and physical examination that distinguish patients with migraine from those with other headache types and that identify those patients who should undergo neuroimaging. DATA SOURCES AND STUDY SELECTION: A systematic review was performed using articles from MEDLINE (1966-November 2005) that assessed the performance characteristics of screening questions in diagnosing migraine (with the International Headache Society diagnostic criteria as a gold standard) and addressed the accuracy of the clinical examination in predicting the presence of underlying intracranial pathology (with computed tomography/magnetic resonance imaging as the reference standard). DATA EXTRACTION: Two authors independently reviewed each study to determine eligibility, abstract data, and classify methodological quality using predetermined criteria. Disagreement was resolved by consensus with a third author. DATA SYNTHESIS: Four studies of screening questions for migraine (n = 1745 patients) and 11 neuroimaging studies (n = 3725 patients) met inclusion criteria. All 4 of the migraine studies illustrated high sensitivity and specificity if 3 or 4 criteria were met. The best predictors can be summarized by the mnemonic POUNDing (Pulsating, duration of 4-72 hOurs, Unilateral, Nausea, Disabling). If 4 of the 5 criteria are met, the likelihood ratio (LR) for definite or possible migraine is 24 (95% confidence interval [CI], 1.5-388); if 3 are met, the LR is 3.5 (95% CI, 1.3-9.2), and if 2 or fewer are met, the LR is 0.41 (95% CI, 0.32-0.52). For the neuroimaging question, several clinical features were found on pooled analysis to predict the presence of a serious intracranial abnormality: cluster-type headache (LR, 10.7; 95% CI, 2.2-52); abnormal findings on neurologic examination (LR, 5.3; 95% CI, 2.4-12); undefined headache (ie, not cluster-, migraine-, or tension-type) (LR, 3.8; 95% CI, 2.0-7.1); headache with aura (LR, 3.2; 95% CI, 1.6-6.6); headache aggravated by exertion or a valsalva-like maneuver (LR, 2.3; 95% CI, 1.4-3.8); and headache with vomiting (LR, 1.8; 95% CI, 1.2-2.6). No clinical features were useful in ruling out significant pathologic conditions. CONCLUSIONS: The presence of 4 simple historical features can accurately diagnose migraine. Several individual clinical features were found to be associated with a significant intracranial abnormality, and patients with these features should undergo neuroimaging.

Algorithms↗

PubMed2003

Neuroimaging studies in the evaluation of developmental delay/mental retardation.

The employment of neuroimaging studies in the evaluation of individuals with developmental delay/mental retardation (DD/MR) is still highly debated. The Consensus Conference of the American College of Medical Genetics has suggested that "neuroimaging appears to have an especially important role in patients with microcephaly or macrocephaly, seizures, loss of psychomotor skills and neurologic signs," whereas the value of neuroimaging investigations "in the normocephalic patient without focal neurological signs is unclear" [Curry et al., 1997]. However, recent literature reports show how the latest neuroimaging techniques (in vivo proton magnetic resonance spectroscopy [H-MRS]) may prove to be useful in the diagnostic process of those individuals with DD/MR and no neurological signs/symptoms. The use of these techniques can, in addition, help in monitoring treatment in distinct metabolic disorders. This review will focus on the usefulness of neuroimaging studies in some of the newer metabolic disorders. This paper will also cover those recognizable patterns of human malformation where neuroimaging findings seem to be relevant both toward diagnosis and management, and add to our understanding of the related behavior phenotype. The essential role of magnetic resonance imaging (MRI) on the progress in the diagnostic recognition of malformations of cerebral cortical development is stressed.

Cerebral Cortex↗

PubMed2006

Cognitive neuroimaging: cognitive science out of the armchair.

Cognitive scientists were not quick to embrace the functional neuroimaging technologies that emerged during the late 20th century. In this new century, cognitive scientists continue to question, not unreasonably, the relevance of functional neuroimaging investigations that fail to address questions of interest to cognitive science. However, some ultra-cognitive scientists assert that these experiments can never be of relevance to the study of cognition. Their reasoning reflects an adherence to a functionalist philosophy that arbitrarily and purposefully distinguishes mental information-processing systems from brain or brain-like operations. This article addresses whether data from properly conducted functional neuroimaging studies can inform and subsequently constrain the assumptions of theoretical cognitive models. The article commences with a focus upon the functionalist philosophy espoused by the ultra-cognitive scientists, contrasting it with the materialist philosophy that motivates both cognitive neuroimaging investigations and connectionist modelling of cognitive systems. Connectionism and cognitive neuroimaging share many features, including an emphasis on unified cognitive and neural models of systems that combine localist and distributed representations. The utility of designing cognitive neuroimaging studies to test (primarily) connectionist models of cognitive phenomena is illustrated using data from functional magnetic resonance imaging (fMRI) investigations of language production and episodic memory.

Brain Mapping↗

PubMed2002

Functional neuroimaging in neurology and psychiatry.

How can functional neuroimaging be applied to clinical neurology and psychiatry? This article reviews selected contributions of functional neuroimaging to the clinical neurosciences. We review selected technical aspects of positron emission tomography, single photon emission tomography, and functional magnetic resonance imaging with a focus on the relative strengths and weaknesses of these techniques. Consumers of functional neuroimaging research are encouraged to consider the limitations of imaging techniques and theoretical pitfalls of cognitive task design when interpreting results of functional imaging studies. Then, we selectively review the contributions of functional neuroimaging to neurology and psychiatry, including the areas of epilepsy, stroke, chronic pain, schizophrenia, depression, and obsessive-compulsive disorder. Future directions of functional neuroimaging research are offered, with the emphasis that the best conclusions are informed by a convergence of research from functional neuroimaging, neurophysiological, and lesion studies.

Journal Article↗

PubMed1996

Diagnostic utility of endocrine and neuroimaging screening tests in first-onset adolescent psychosis.

OBJECTIVE: To determine the diagnostic utility of endocrine and neuroimaging screening tests in first-onset adolescent psychosis. METHOD: 111 consecutively admitted adolescents (aged 13 through 19 years) who presented with a first-onset psychosis and who had an unremarkable medical history and normal physical examination were given a battery of endocrine and neuroimaging screening tests. Diagnostic utility of a screening test was defined as an abnormal result (a positive test) that either led to a previously unknown or unsuspected medical diagnosis or played an important role in the clinical care of the patient. RESULTS: 15.4% of the endocrine screening tests and 11.0% of the neuroimaging screening tests were identified as positive. However, no endocrine and no neuroimaging tests met criteria for diagnostic utility. The direct cost of this screening battery was $636.95 per patient. CONCLUSION: Routine endocrine and neuroimaging screening tests in first-onset adolescent psychosis provide no diagnostic utility and are not cost-effective. Selective use of appropriate endocrine and neuroimaging diagnostic tests in populations with symptoms suggestive of organic disorders should replace routine screening procedures.

Adolescent↗

PubMed1996

The effect of multiple neuroimaging studies on classification, treatment, and outcome of acute ischemic stroke.

OBJECTIVE: To examine the effect of serial neuroimaging studies on the diagnosis, therapy, and outcome of patients with acute stroke. DESIGN: Retrospective case series. SETTING: Tertiary care teaching hospital. PATIENTS: 206 adult patients (mean age +/- SD, 66.0 +/- 10.8 years) hospitalized with a diagnosis of acute stroke between 1990 and 1993. MEASUREMENTS: Strokes were retrospectively assigned to five categories (large-vessel, small-vessel, cardioembolic, other, or unknown) using standardized criteria based on the history, physical examination, ancillary test results, and first computed tomographic (CT) or magnetic resonance imaging (MRI) study of the head. Strokes were reclassified after the results of further neuroimaging studies, if any, were reviewed. The type and timing of therapy and the patient outcome at hospital discharge were documented. RESULTS: The additional studies changed stroke classification in only 20.0% of the 140 patients who had two or more neuroimaging studies. All classification changes were from the unknown cause category to a category with a specific cause. In most patients receiving treatment (93.2%), therapy began before an additional CT or MRI study was obtained. In patients who had one neuroimaging study, 70.1% went home, 24.0% went to a skilled nursing facility, and 5.9% died; the corresponding percentages in persons who had multiple studies were 73.3%, 24.4%, and 2.2% (P > 0.1). CONCLUSIONS: Serial neuroimaging studies did not alter the classification of strokes for which an initial diagnosis had already been made. However, they were useful in determining the cause of strokes initially classified as having an unknown cause. Therapy was almost always begun immediately after the first CT or MRI study was obtained. Outcome at hospital discharge was not significantly related to the number of neuroimaging studies obtained.

Aged↗

PubMed2006

Neuroimaging features of tuberculous meningitis.

Tuberculous meningitis leads to a high mortality rate. However, it responds well to chemotherapy if the treatment is started early. Neuroimaging is one of the most important initial investigations. There were 42 patients diagnosed with tuberculous meningitis in Kuala Lumpur Hospital based on clinical criteria, cerebrospinal fluid analysis and response to anti-tuberculous treatment over a 7 year period. Relevant information was obtained from patients' medical case notes and neuroimaging findings were evaluated. Male to female ratio was 3:1. The three major ethnics and the immigrant groups in Malaysia were represented in this study. The majority of the cases involved the Malays followed by immigrants, Chinese and Indians. The patients' age ranged from 18 to 62 years old with the mean age of 34.4 years. There were 95.2% (n = 40) of patients who presented with various neuroimaging abnormalities and only 2 (4.8%) patients had normal neuroimaging findings. Hydrocephalus and meningeal enhancement were the two commonest neuroimaging features. Other features include infarction, enhancing lesion, tuberculoma, abcess, oedema and calcification. Contrasted CT scan is an adequate neuroimaging tool to unmask abnormal findings in tuberculous meningitis.

Adolescent↗

PubMed2004

Methods for detecting functional classifications in neuroimaging data.

Data-driven statistical methods are useful for examining the spatial organization of human brain function. Cluster analysis is one approach that aims to identify spatial classifications of temporal brain activity profiles. Numerous clustering algorithms are available, and no one method is optimal for all areas of application because an algorithm's performance depends on specific characteristics of the data. K-means and fuzzy clustering are popular for neuroimaging analyses, and select hierarchical procedures also appear in the literature. It is unclear which clustering methods perform best for neuroimaging data. We conduct a simulation study, based on PET neuroimaging data, to evaluate the performances of several clustering algorithms, including a new procedure that builds on the kth nearest neighbor method. We also examine three stopping rules that assist in determining the optimal number of clusters. Five hierarchical clustering algorithms perform best in our study, some of which are new to neuroimaging analyses, with Ward's and the beta-flexible methods exhibiting the strongest performances. Furthermore, Ward's and the beta-flexible methods yield the best performances for noisy data, and the popular K-means and fuzzy clustering procedures also perform reasonably well. The stopping rules also exhibit good performances for the top five clustering algorithms, and the pseudo-T2 and pseudo-F stopping rules are superior for noisy data. Based on our simulations for both noisy and unscaled PET neuroimaging data, we recommend the combined use of the pseudo-F or pseudo-T2 stopping rule along with either Ward's or the beta-flexible clustering algorithm.

Algorithms↗

PubMed2001

Neuroimaging studies of the hippocampus in schizophrenia.

Three neuroimaging techniques, morphometric neuroimaging, magnetic resonance spectroscopy, and functional neuroimaging, have provided evidence for abnormal hippocampal structure and function in schizophrenia. Hippocampal volume reduction is now one of the most consistent structural abnormalities found in schizophrenia: it is present at the onset of the illness and, to a lesser degree, in first-degree relatives of schizophrenic probands. Decreased levels of N-acetyl-aspartate point towards a cellular basis of such volume changes. Functional neuroimaging studies have demonstrated abnormal levels of hippocampal activity at rest, during the experience of auditory hallucinations, and during the performance of memory retrieval tasks. These results of neuroimaging studies complement evidence from post-mortem and behavioral studies, which have found regionally specific abnormalities of the hippocampus and of memory function in schizophrenia.

Cerebrovascular Circulation↗

PubMed2004

Neuroimaging in mental retardation.

OBJECTIVE: To determine the diagnostic yield of neuroimaging in a cohort of children with mental retardation of unknown origin. METHODS: Neuroimaging was performed in a total of 47 patients with developmental delay/mental retardation, where no etiologic diagnosis could be made following clinical examination and preliminary investigations. RESULTS: Thirty (63.82%) children had abnormal neuroimaging findings of which 19 (42.42%) were specific abnormalities useful in arriving at etiological diagnosis. Positive outcome of neuroimaging increased with the severity of mental retardation and in presence of microcephaly and neurologic deficits other than mental retardation. CONCLUSION: Neuroimaging should be the standard clinical practice for a child with global developmental delay where no cause is apparent after examination and relevant investigations.

Adolescent↗

PubMed2006

Neuroimaging research in human MDMA users: a review.

RATIONALE: Determining whether, under what circumstances, and to what extent 3,4-methylenedioxymethamphetamine (MDMA) exposure produces chronic changes in human brain function is a critical public health issue. MDMA is a widely used recreational drug commonly sold as "Ecstasy". Because findings from the animal literature have indicated that specific dosage regimens of MDMA can produce long-lasting alterations in serotonergic function, existing studies of MDMA effects in humans have examined brain serotonin (5-HT) transporters (5-HTT) and receptors or have examined brain structures or functions potentially affected by MDMA. OBJECTIVES: The objectives of this review are to provide a background for interpreting human MDMA neuroimaging research, to examine existing neuroimaging data regarding the rationale for and limitations to human MDMA research, and to provide suggestions for improving the design and interpretation of future neuroimaging approaches. RESULTS: Of the existing neuroimaging studies in human MDMA users, few experimental designs have been replicated across different research groups. Only investigations employing nuclear imaging methods to assay brain 5-HTT levels have been replicated across methods and research laboratories. These studies have found reduced levels of the 5-HTT in recently abstinent MDMA users with some evidence for normalization of 5-HTT levels with prolonged abstinence. However, the sensitivity of these methods is unknown. CONCLUSIONS: The current state of neuroimaging in human MDMA users does not permit conclusions regarding the long-term effects of MDMA exposure. Future study designs might benefit from improved sample homogeneity, increased length of MDMA abstinence, longitudinal study design, test-retest measures, serotonergic specificity, and multimodal approaches.

Amphetamine-Related Disorders↗