SEARCH · PubMed Health

Results for “brain imaging”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

PubMed2000

Predictive value of clinical lacunar syndromes for lacunar infarcts on magnetic resonance brain imaging.

OBJECTIVE: We prospectively investigated the predictive value of clinical and CT-supported lacunar syndromes for lacunar infarcts on magnetic resonance (MR) brain imaging. PATIENTS AND METHODS: The 54 prospective, consecutive patients had clinical lacunar syndromes of acute onset and early computed tomography (CT; on admission day, i.e. < or =48 h after onset of symptoms) showing either a small deep infarct or no corresponding lesion. Taking MR (at day 2 to 4 after admission) as the gold standard, the positive predictive value of the CT-supported clinical syndrome for corresponding lacunar lesions was calculated. RESULTS: In 27 (50%) patients, early CT showed a lacunar infarct corresponding to the clinical syndrome, a further 27 (50%) patients had no fresh ischemic lesion. In 51 patients (94%), MR showed a recent lacunar infarct (hyperintense lacune in T2-weighted scans, no demarcation on T1-weighted scans and/or positive gadolinium-enhancement) corresponding to the clinical syndrome (positive predictive value 0.94, 95%, CI: 0.88 to 0.98). In 3 (6%) patients MR was normal. Aside from old unrelated ischemic (macro- and/or microangiopathic) lesions, MR revealed no acute non-lacunar infarct. CT and MR sites of lacunar lesions were matching. Compared to gold standard MR, the sensitivity of early CT for suspected lacunar lesions was 0.53 (95% CI: 0.38 to 0.67). CONCLUSION: Lacunar syndromes were highly predictive for small deep infarcts on MR. Magnetic resonance brain imaging may be redundant in the setting of a lacunar syndrome supported by a CT that excludes non-ischemic causes of stroke; it may therefore be abandoned in order to reduce costs in the health care system.

Adult↗

PubMed1977

Role of the radionuclide brain image in the diagnosis of brainstem gliomas.

The noninvasive detection of brainstem gliomas remains difficult. Eleven of our patients with proven brainstem gliomas had radionuclide brain imaging prior to the initiation of therapy or confirmation of the diagnosis; six studies were positive. Pneumoencephalography remains the most reliable diagnostic test for brainstem glioma, and is invariably required for confirmation. Although angiography is useful in the evaluation of vasocularity it may not detect small infiltrating lesions. Radionuclide brain imaging is useful in the initial workup of patients with suspected brainstem gliomas.

Adult↗

PubMedDate not supplied

Posterior fossa abnormalities seen on magnetic resonance brain imaging in a cohort of newborn infants.

OBJECTIVE: To describe the nature and frequency of posterior fossa (PF) lesions in infants who underwent magnetic resonance (MR) brain imaging in the neonatal period and to correlate with cranial ultrasound (CUS) findings and clinical outcome. STUDY DESIGN: A retrospective review of all neonatal MR brain imaging from 1996 to 2001 (n=558). MR images, CUS and case notes were reviewed in infants with PF abnormality. RESULTS: A total of 20 infants had abnormalities in the PF, which represents 4.7% of abnormalities seen on MR. Out of 10, six term infants had PF extra-axial hemorrhage, three had cerebellar hypoplasia, while one had cerebellar hemorrhage. In the preterm, 8/10 lesions were unilateral; focal cerebellar hemorrhage was seen in 5/10 and extensive hemorrhage with secondary atrophy in 3/10. Out of 20, 17 infants also had supratentorial lesions. Out of 20, 19 had CUS performed, of which 7/19 showed PF abnormality. CONCLUSION: Intracerebellar hemorrhage was more common in preterm infants than in term infants. These hemorrhages tended to be focal, unilateral and were associated with atrophy.

Birth Weight↗

PubMed2003

Contributions from brain imaging to the elucidation of pathophysiology of bipolar disorder.

Over the past two decades, brain-imaging studies have examined the mechanisms possibly involved in the pathophysiology of bipolar and unipolar mood disorders. The available findings suggest subtle anatomical changes in sub-regions of the prefrontal cortex, medial temporal lobe and cerebellum, and functional abnormalities in brain circuits inter-connecting these same brain regions and the striatum in patients suffering from bipolar disorder. 1H magnetic resonance spectroscopy (MRS) studies reported decreased N-acetyl aspartate (NAA) levels in the dorsolateral prefrontal cortex, and 31P-MRS studies found abnormalities in membrane phospholipids in frontal and temporal regions in bipolar individuals. Few studies have utilized in-vivo receptor imaging to study bipolar patients. Even though preliminary findings from cross-sectional studies indicate anatomical, neurochemical, and functional brain abnormalities in bipolar patients in key regions involved in mood regulation, the relationship of such abnormalities with illness phase and their clinical relevance needs further investigation. The potential for utilization of brain-imaging tools to elucidate the pathophysiology of bipolar disorder is still largely unrealized, and it is anticipated that important new developments in this area will come about over the next years and beyond.

Bipolar Disorder↗

PubMed2003

Equivalence of cognitive processes in brain imaging and behavioral studies: evidence from task switching.

A growing number of studies on the higher-order cognitive functions of the human brain use brain-imaging techniques, such as functional magnetic resonance imaging (fMRI). For the validity and generality of fMRI results, it is important that the relevant cognitive processes are equivalent to those functioning in typical settings used in behavioral research. This equivalence could be, for example, endangered by different spatial frames of reference when lying in the scanner. In the present study, we tested whether the cognitive processes, as reflected in behavioral data in brain-imaging settings, are indeed functionally equivalent to those reflected in "purely" behavioral settings. To this end, we used a task-switching paradigm with a spatial component, increasing the likelihood to find effects of experimental setting. We compared the data of three different groups that only differed in testing environments (real, operating fMRI vs simulated fMRI vs standard behavioral with upright position of participants) but used otherwise strictly equivalent experimental conditions. Of importance for our validation purposes, unlike previous studies, we included a group with a behavioral setting, and we tested whether we would replicate a nontrivial, complex three-way interaction across all three groups. We replicated the predicted complex data pattern in all groups, suggesting functional equivalence of the underlying cognitive processes. We also found strongly increased reaction time (RT) levels in the two fMRI groups. We attribute this increase to unspecific distracting factors affecting late motor processes and discuss potential methodological implications of this increased baseline RT in the scanner.

Adolescent↗

PubMed1980

Tomograpy in radionuclide brain imaging and cisternography.

A new radionuclide tomographic scanner produces 12 tomographic brain images instead of a single conventional brain scan. This scanner has important advantages over conventional radionuclide scanning. The size, shape, and extent of a lesion and its relationship to surrounding structures are better defined. Tomography often permits a firm diagnostic impression in studies that would be equivocal with the use of routine scanning. Tomography may also be used in conjunction with radionuclide cisternography to provide a clear visualization of the CSF pathways and ventricles and to distinguish overlying structures.

Adult↗

PubMed2005

Update on brain tumor imaging.

Brain tumor imaging has evolved from a strictly morphology-based discipline to one that encompasses function, physiology, and anatomy, enabled by advances in imaging and computer technology. This review outlines the current imaging standard for patients with brain tumors and summarizes the latest advances in physiology-based imaging methods that complement traditional brain tumor imaging protocol. Emphasis is placed on the strengths and limitations of the current imaging standards and on an overview of several advanced imaging methods, including diffusion-weighted magnetic resonance imaging, perfusion magnetic resonance imaging, and proton magnetic resonance spectroscopic imaging. Basic physical principles behind each imaging method are briefly presented, along with a more in-depth discussion of the clinical applications and potential pitfalls of each technique.

Brain Neoplasms↗

PubMed1997

Functional brain imaging with cerebral perfusion SPECT in cerebrovascular disease, epilepsy, and trauma.

Functional brain imaging with cerebral perfusion single-photon emission computed tomography (SPECT) has practical and important applications for use by neurosurgeons in the evaluation of cerebrovascular disease, stroke, epilepsy, and trauma. The radiopharmaceuticals used in SPECT enable one to image a "snapshot" of regional cerebral blood flow. The findings on SPECT can be the most sensitive and unique descriptors of dynamic alterations in brain function due to the aforementioned disorders. Used in conjunction with other imaging modalities such as magnetic resonance imaging, CT, and neurodiagnostic tests such as EEG and TCD, the brain blood flow images enhance the ability of the neurosurgeon to determine the perfusion status of the brain.

Brain↗

PubMed1992

Marchiafava-Bignami disease. A case studied by structural and functional brain imaging.

Marchiafava-Bignami disease (MBD) is a rare complication of chronic alcoholism. The clinical features, X-ray, CT and MRI findings are well documented. However, functional brain imaging has not been used in cases of MBD. We used single-photon emission computed tomography (SPECT) to monitor the regional cerebral blood flow in a patient suffering from a acute form of MBD, from which he subsequently recovered. Several abnormalities were found. A more frequent use of functional brain imaging in MBD could improve our knowledge of pathogenesis and prognosis for MBD.

Adult↗

PubMed1996

Utility of repeat brain imaging in stroke.

PURPOSE: To determine the utility of repeat brain imaging in patients with stroke. METHODS: We reviewed the medical records of 98 consecutive patients in whom stroke was diagnosed between January 1 and December 31, 1991. We noted the number of brain scans performed, the indications cited, and whether repeat imaging changed the therapeutic decisions or final diagnosis. RESULTS: Ninety-eight patients underwent 221 procedures, with 123 repeat imaging studies (98 CT scans and 25 MR images). Sixteen patients had only one scan; 51 had two, and 31 had three or more. Indications for repeat imaging were explicitly documented in 62 (50%) of 123 repeated scans and inferred in another 41 (33%). In 20 (16%), no definite indication could be determined. Indications included lack of acute abnormal imaging findings on the initial scan (n = 48, 39%); compliance with stroke research protocol (n = 11, 9%). In none of the 82 patients did the repeated scan change the diagnosis; therapy was changed in only two (2%) of 82 patients (aspirin was discontinued). CONCLUSIONS: Repeat imaging in patients rarely results in changes in the initial diagnosis or the therapeutic plan; indications for repeat imaging are frequently not clearly stated; in certain groups of patients with stroke, repeat imaging may not be useful.

Aged↗

PubMed1999

The impact of brain imaging technology on our understanding of motor function and dysfunction.

Brain imaging techniques have demonstrated functional specialisation of multiple areas within the motor system. They have also defined the patterns of interactions between these regions during normal motor function and in motor disorders. Functional imaging makes visible the changes in cortical activity that take place over time during motor functions, from the activations a fraction of a second before voluntary action to cortical neuronal plasticity several weeks after injury. Recently, the functional abnormalities underlying various acquired and developmental motor disorders have been described, as well as the effects of therapeutic intervention.

Brain↗

PubMed2005

Brain imaging in drug R&D.

Magnetic resonance imaging (MRI), used as a clinical diagnostic tool since the early 1980s, is rapidly gaining traction as an integral part of the drug development process. Brain imaging research spans a wide area, covering both structure and function, and ranging from the physics and physiology associated with novel acquisition techniques, to the development of sophisticated image processing algorithms. This paper briefly describes two methods on either end of this spectrum: the "pipeline" framework for the fully automated morphometric analysis of brain imaging data, and molecular MRI, which holds promise for the non-invasive detection of molecular targets of new pharmacological compounds. The potential use of these technologies is illustrated by examples of their applications in multiple sclerosis, Alzheimer's disease, and oncology.

Algorithms↗

PubMed2026

Is impulsivity simply a failure of self-control? Evidence based on multi-omics analyses of genomics, metabolomics and brain imaging.

High impulsivity-a hallmark of various adverse life outcomes such as substance abuse, impulsive buying, violence, and crime-has typically been considered as a failure of self-control. However, is impulsivity simply a failure of self-control? To address this issue, we employed multi-omics combined with brain imaging approach in a large-scale sample (Nbrain imaging=1524, Ngenomics=835, Nmetabolomics=946) to elucidate the relationship between impulsivity and self-control. Mendelian randomization showed a bidirectional association between impulsivity and self-control, suggesting that they influenced each other. Partial least squares analysis highlighted that self-control primarily implicates the frontal lobe regions (e.g., superior frontal gyrus), whereas impulsivity involves the amygdala, insula, and basal ganglia. The cerebellum, superior frontal gyrus, and middle frontal gyrus were identified as shared areas in impulsivity and self-control. Furthermore, gene-based association analysis identified heterochromatin protein 1 binding protein 3 as specifically related to impulsivity, while pathway enrichment analysis demonstrated that arginine and proline metabolism was a common metabolic pathway associated with both impulsivity and self-control. Overall findings demonstrate that impulsivity and self-control involve both shared and distinct brain regions, genetic and metabolic foundations. The brain imaging results suggest that impulsivity is related not only to self-control-related processes but also to the motivation to pursue rewards. Together, this large-scale integrative study firstly provides a side-by-side map of genomic, metabolic, and limbic-network signatures of impulsivity distinct from self-control, offering a foundation for mechanism-driven biomarker and intervention research in maladaptive impulsivity.

Impulsive Behavior↗

PubMed1997

Integration of functional and anatomical brain images.

This article concerns the integration of functional and anatomical volumetric brain images. Integration consists of two steps: matching or registration, where the images are brought into spatial agreement, and fusion or simultaneous display where the registered multimodal image information is presented in an integrated fashion. Approaches to register multiple images are divided into extrinsic methods based on artificial markers, and intrinsic matching methods based solely on the patient related image data. The various methods are compared by a number of characteristics, which leads to a clear preference for one class of intrinsic methods, viz. voxel-based matching. Furthermore, two- and three-dimensional techniques to display multimodality image information are outlined.

Brain↗

PubMed1985

Synthesis of new bis(aminoethanethiol) (BAT) derivatives: possible ligands for 99mTc brain imaging agents.

In developing new brain perfusion imaging agents for single photon emission computed tomography (SPECT), five 99mTc-labeled neutral bis(aminoethanethiol) (BAT) derivatives capable of crossing the blood-brain barrier are reported. The five ligands are prepared by two versatile synthetic methods that can specifically introduce substituents on one of the carbons between two nitrogens. These ligands formed stable and neutral complexes with the reduced 99mTc, using either Sn(II) or sodium borohydride to reduce sodium [99mTc]pertechnetate. The biodistribution in rats was evaluated with [125I]iodoantipyrine, a freely diffusible tracer, as the internal reference. Compounds with a free hydroxyl group, 6 and 15, showed lower brain uptake. High initial brain uptake was observed for compounds 10 and 14, 1.28 and 2.30% dose/organ, respectively. Compounds of this type may be used as a basis for future structural modification to improve brain uptake and retention.

Animals↗

PubMedDate not supplied

Cardiovascular diseases, health status, brain imaging findings and neuropsychological functioning in neurologically healthy elderly individuals.

The aim of our study was to evaluate the relationship between health-related factors, brain imaging findings and cognitive functioning. We examined 113 neurologically healthy subjects from 55 to 85 years of age. Health-related variables included a clinical health evaluation, cardiovascular diseases, and other systemic diseases. The presence of white matter changes and cerebral and peripheral atrophy were obtained with magnetic resonance imaging. Neuropsychological tests measuring verbal memory, visual memory, intellectual and language functions, visuoconstructional functions, flexibility, and speed and attention were administered. Results showed that overall health status was not related to cognition. Subjects, who had both arterial hypertension and white matter changes had difficulties in flexibility. Cardiac failure and white matter changes were related to impairment in visuoconstructional functions, flexibility and attention. Significant speed and attention deficits were observed in subjects with cardiac failure and central atrophy. In conclusion, this study verifies the relationship between hypertension, white matter changes and cognitive functions. We found also specific patterns in relation with cardiac failure, brain imaging findings and cognitive functioning, the most vulnerable domains were visuoconstructional functions, flexibility and attention.

Journal Article↗

PubMed1996

Crossed aphasia. Functional brain imaging with PET or SPECT.

OBJECTIVES: To study patients with crossed aphasia (aphasia secondary to lesions in the right hemisphere in right-handed patients) with functional brain imaging using positron emission tomography (PET) or single photon emission computed tomography (SPECT); to see whether left hemisphere structures were metabolically depressed during the acute phase and, in 1 patient, during recovery; and to review the modern literature on crossed aphasia, with special reference to left hemisphere involvement. DESIGN: Case studies of 3 patients with crossed aphasia, including language testing, computed tomographic scanning, and functional imaging with PET or SPECT. SETTING: Hospital case studies. PATIENTS: Three right-handed patients with crossed aphasia secondary to acute infarctions in the right hemisphere and left hemiparesis. METHODS: All 3 patients were studied by means of bedside language testing, computed tomographic scanning, and functional brain imaging with PET or SPECT. Patient 1 also underwent serial testing with the Boston Diagnostic Aphasia Examination and follow-up PET scanning after 2 months of recovery. OUTCOME MEASURES: Clinical examination in all 3 patients and follow-up Boston Diagnostic Aphasia Examination and PET scanning in patient 1. RESULTS: Two patients had severe global aphasia and 1 had Broca aphasia. In all cases, computed tomographic scans failed to reveal any left hemispheric lesions. Functional imaging with PET or SPECT showed extensive hypometabolism or hypoperfusion in the right hemisphere, with initial reductions in the left hemisphere as well. In patient I, a follow-up PET image showed only persistent hypometabolism in the right hemisphere. CONCLUSIONS: These findings suggest that abnormal dominance for at least some language functions in the right hemisphere underlies the syndrome of crossed aphasia. Diaschisis, or functional depression of the anatomically normal left hemisphere, was seen in all 3 patients during the acute phase, but not in patient 1 after recovery had begun.

Aged↗

PubMed1995

Functional brain imaging studies of cortical mechanisms for memory.

Recent functional brain imaging studies in humans indicate that learning and memory involve many of the same regions of the cortex that process sensory information and control motor output. The forms of perceptual and motor learning that can occur without conscious recollection are mediated in part by contractions and expansions of representations in the sensory and motor cortex. The same regions are also engaged during the conscious storage and retrieval of facts and events, but these types of memory also bring into play structures involved in the active maintenance of memories "on line" and in the establishment of associative links between the information stored in different sensory areas. Although the picture of memory that is emerging from functional imaging studies is consistent with current physiological accounts, there are puzzles and surprises that will be solved only through a combination of human and animal studies.

Animals↗