Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Neuroimaging”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 577 records · Page 32Linked to original sources
PubMed2001

Cerebral ganglioglioma with epilepsy: neuroimaging features and treatment.

Gangliogliomas are an increasingly recognized cause of epilepsy in children. In this study the clinical, neuroimaging, and neurophysiological data of five patients with cerebral ganglioglioma and epilepsy are reviewed retrospectively. The average age of these patients was 4.4 years at onset and the average duration of seizures before diagnosis was 11 months. Tumors were located in the frontal (3), parietal (1), and occipital (1) lobes. While one cystic and four solid tumors showed various densities on CT and MRI, one frontal lesion was not demonstrated by CT scan but clearly shown by MRI. Scalp electroencephalography (EEG) showed neither localized nor epileptiform abnormalities in three patients, while the remaining two had these abnormalities. In one patient, invasive chronic electrocorticography (ECoG) recordings with subdural electrodes revealed an ictal onset zone located in the hand motor area. In all patients, intraoperative ECoG failed to reveal any epileptiform activities, and tumor removal alone was performed. For a mean of 3.4 years after surgery, all patients are alive and seizure-free, with stable imaging findings. Tumor resection may be the most important factor for optimal seizure control and prevention of tumor recurrence despite the fact that EEG and ECoG findings may conflict on tumor location.

Adolescent↗
PubMed2004

[Neuroimaging in substance abuse disorders].

The use of neuroimaging techniques in research on substance abuse disorders has advanced our understanding of the underlying pathophysiological and neuropsychological mechanisms. While initial structural imaging techniques were applied to investigate substance abuse-related cerebral atrophy, the functional techniques of SPECT, PET, and later fMRT and MRS provide a much broader range of possible research in this field. Besides their use in characterizing the pharmacology of abused substances and their relations to the pathophysiology of substance abuse disorders, they have also played an essential role in examining the neuropsychiatric underpinnings of the illness and their manifestation in changes of cerebral metabolism. Here, the influence of these techniques on the developing picture of substance abuse disorders is discussed by examining areas of particular scientific interest and reviewing exemplary findings.

Alcoholism↗
PubMed2006

[Neurophysiological and neuroimaging studies for restless legs syndrome and periodic leg movement disorder].

The restless legs syndrome (RLS) is a clinical diagnosis based on the four essential criteria defined by the International Restless Legs Syndrome Study Group (IRLSSG). An idiopathic form can be separated from a symptomatic form. Neurophysiological studies have investigated the pathophysiology of the idiopathic RLS or have been used to exclude a symptomatic cause, in particular polyneuropathy. So far cortical excitability changes, corticomotor, somatosensory and auditory pathways, spinal cord excitability, B-wave rhythm and cycling alternating pattern, as well as reflex mechanisms have been investigated by electroencephalography, evoked potentials, Bereitschaftspotentials, nerve conduction and thermal threshold measurements, electromyography, transcranial Doppler sonography, measurements of the spinal flexor reflex as well as neuroimaging techniques. The etiology of the RLS cannot be revealed by these methods, neurophysiological studies in RLS are, however, useful for a better understanding of the pathophysiology and for exclusion of a polyneuropathy or other symptomatic causes. In addition to neurophysiological investigations, small fiber neuropathy, which seems to be a more common finding in RLS patients than expected to date, may need biopsy for confirmation. This review will focus on investigations of the different systems involved with diverse neurophysiological methods.

Brain↗
PubMed2006

Neuroimaging and electrophysiological studies of the effects of acute tryptophan depletion: a systematic review of the literature.

RATIONALE: There is a growing psychopharmacological literature on the use of Acute Tryptophan Depletion (ATD) for experimental modulation of the serotonergic system. To date, no systematic review has been undertaken assessing the neurophysiological effects following this acute central 5-HT manipulation. MATERIALS AND METHODS: A comprehensive MEDLINE, EMBASE, PsycINFO search was performed for reports on neural substrates of Acute Tryptophan Depletion in healthy individuals and in clinical population. RESULTS: Twenty-eight placebo-controlled studies were included in the review. Although tryptophan depletion reduced plasma serotonin levels in all studies, significant effects on mood were only observed in studies with recovered depressed patients. In functional neuroimaging studies ATD was consistently found to modulate cortical activity in prefrontal areas implicated in mnemonic and executive functions and in orbitofrontal, cingulate, and subcortical regions associated with emotional processing. Electrophysiological studies indicated that ATD has a significant effect on both "selective" and "involuntary" attention. CONCLUSIONS: The combination of ATD with modern brain imaging techniques allows the investigation of the neurophysiological effects of reduced 5-HT synthesis on global brain activity, executive functions, memory, attention, and affect.

Electroencephalography↗
PubMed2001

Cocaine-induced brain activation determined by positron emission tomography neuroimaging in conscious rhesus monkeys.

RATIONALE: Cerebral blood flow can provide a useful dependent measure to characterize cocaine-induced changes in brain function. The acute effects of cocaine administration on cerebral blood flow may have direct relevance to the etiology of cocaine addiction. OBJECTIVES: The present study used positron emission tomography (PET) neuroimaging techniques to characterize the acute effects of cocaine administration on cerebral blood flow in conscious rhesus monkeys. METHODS: Functional changes in cerebral blood flow were determined in four drug-naive subjects with the positron-emitting tracer 15O water following acute i.v. administration of cocaine (0.3 and 1.0 mg/kg). Specific attention was devoted to the development of an effective and comfortable head restraint device to use in the imaging of conscious monkeys. Experimental sessions comprised eight consecutive i.v. injections of 15O water at 10-min intervals. PET scans of 90 s duration occurred 10 s after each injection. RESULTS: Repeated baseline determinations of cerebral blood flow prior to drug administration were reliable. Cocaine had significant, dose-related effects on cerebral blood flow at 5 min postinjection that diminished relative to control (saline) conditions by 15 min postinjection. Brain activation maps normalized to global flow showed prominent cocaine-induced activation of prefrontal cortex localized primarily to dorsolateral regions. Importantly, cocaine-induced brain activation was blocked by pretreatment with the selective serotonin uptake inhibitor, alaproclate (3.0 and 10.0 mg/kg). The results document a distinct pattern of cocaine-induced brain activation that is sensitive to pharmacological manipulation. CONCLUSION: The pattern of brain activation induced by acute administration of cocaine may provide a useful means to evaluate medication effectiveness for treating cocaine addiction.

Animals↗
PubMed2002

Neuroimaging supports the clinical diagnosis of methanol poisoning.

In addition to visual loss, methanol intoxication can cause brain damage that is revealed by neuroimaging. We report on a 34-year-old man whose visual acuity deteriorated dramatically during his journey round the world, shortly after an evening with excessive alcohol consumption. Two months after the start of visual disturbances he returned to Finland. At examination, poor visual acuity and glaucomatously cupped pale optic discs were detected. The history and clinical findings indicated possible methanol intoxication, which was supported by both CT and MRI. The MRI findings are discussed in the light of the MRI appearance of the pallidum nuclei among patients of different age groups.

Adult↗
PubMed2006

Idiopathic intracranial hypertension: the validity of cross-sectional neuroimaging signs.

The aim of this study was to evaluate the accuracy of previously reported neuroimaging signs in establishing or excluding the diagnosis of idiopathic intracranial hypertension (IIH). In a retrospective study, 30 patients with confirmed IIH and 56 controls were evaluated with brain magnetic resonance imaging. All examinations were evaluated in a blinded fashion by three neuroradiologists for the presence or absence of the 'traditional' signs of IIH: empty sella turcica, deformation of the pituitary, slit-like ventricles, 'tight' subarachnoid spaces, flattening of the posterior globe, protrusion of the optic nerve, enhancement of the optic nerve head, distension of the optic nerve sheath and vertical tortuosity of the optic nerve. Optic nerve protrusion and enhancement, slit-like ventricles and tight cerebrospinal fluid spaces were not significantly associated with IIH (P>0.05). Posterior globe flattening, optic nerve sheath distension, optic nerve tortuosity, pituitary deformity and empty sella turcica were significantly associated with IIH (P<0.05). However, most of these are not helpful in a clinical setting, with the exception of posterior globe flattening. This is the only sign that, if present, strongly suggests the diagnosis of IIH (specificity 100%, 95% CI 93.6% to 100%; sensitivity 43.5%, 95% CI 27.3% to 60.8%; positive likelihood ratio 49.7). The majority of the reported signs for IIH on cross-sectional imaging are not helpful in establishing or excluding the diagnosis of IIH, and are of no value in the clinical setting. Flattening of the posterior aspect of the globe is the only sign that, if present, is suggestive of the diagnosis of IIH.

Adult↗
PubMed2002

Neuroimaging abnormalities in Griscelli's disease.

Griscelli's disease is a rare autosomal recessive immunodeficiency syndrome. We report a 7-1/2-month-old white girl who presented with this syndrome, but initially without neurological abnormalities. Initial CT of the brain was normal. Despite haematological remission with chemotherapy, she developed neurological symptoms, progressing to coma. At this time, CT showed areas of coarse calcification in the globi pallidi, left parietal white matter and left brachium pontis. Hypodense areas were present in the genu and posterior limb of the internal capsule on the right side, as well as posterior aspects of both thalami, together with minimal generalised atrophy. MRI revealed areas of increased T2 signal and a focal area of abnormal enhancement in the subcortical white matter. Griscelli's disease should be added to the list of acquired neuroimaging abnormalities in infants.

Albinism↗
PubMed2002

Neuroimaging findings in neonates and infants from superior vena cava obstruction after cardiac operation.

BACKGROUND: Extraventricular obstructive hydrocephalus may develop after superior vena cava obstruction, an uncommon complication after cardiac surgery. OBJECTIVE: To describe the neuroimaging findings in neonates and infants with superior vena cava thrombosis after cardiac surgery for congenital heart disease. MATERIALS AND METHODS: Between 1993 and 2001, 333 neonates and infants in our hospital underwent cardiac surgery, of whom 13 (3.9%) subsequently acquired superior vena cava syndrome. Eleven of these 13 children (7 boys, 4 girls) were evaluated by head ultrasound and computed tomography scans. RESULTS: One child had normal findings on head ultrasound, and 10 children had extraventricular obstructive hydrocephalus (EVOH). In 6 children, aggravation of the hydrocephalus was noted up to 11.4 months after cardiac surgery; in 3 of them, the hydrocephalus was shunted to the peritoneum. One child had thrombosis of the dural sinuses, and 1 had hemorrhagic infarction. Two children died during follow-up. CONCLUSION: EVOH is a common complication of superior vena cava thrombosis, and head ultrasound should be performed in all neonates and infants with superior vena cava thrombosis after cardiac surgery. Long-term follow-up is needed, as the hydrocephalus may worsen even months after surgery.

Female↗
PubMed2006

New advances in fetal MR neuroimaging.

MR is now routinely and widely used in fetal neuroimaging and has proven to be valuable in the detection of many cerebral lesions, either genetically determined or acquired in utero. However, its efficiency has certain limits in the detection of diffuse white-matter abnormalities, the evaluation of fibre development and the demonstration of metabolic disorders. Moreover, conventional fetal MR imaging provides only a morphological approach to the fetal brain. New techniques such as diffusion-weighted imaging, diffusion tensor imaging, proton MR spectroscopy and functional MR imaging are developing. The majority of these are not used routinely. The principles, aims, technical problems and possible applications of these techniques for imaging the fetus are discussed.

Brain↗
PubMed2003

Is correction for age necessary in neuroimaging studies of the central serotonin transporter?

The central neurotransmitter serotonin plays a major role in a number of neuropsychiatric disorders. However, results from post-mortem and in vivo neuroimaging studies of the influence of age on the number of presynaptic serotonin transporters (SERT) are controversial. To provide further evidence of relevance for this ongoing discussion, SERT were imaged in 22 persons without neuropsychiatric impairment using [(123)I]2beta-carbomethoxy-3beta-(iodophenyl)tropane ([(123)I]beta-CIT) and high-resolution single-photon emission tomography (SPET). The SPET analysis method was based on magnetic resonance image co-registration in order to quantify SERT with acceptable inter- and intra-observer variability. Using this technique, we found a significant age-related decline in the thalamic/hypothalamic and midbrain/upper brainstem SERT density, which was more pronounced than that previously reported in the literature. From these results we conclude that age-related changes in SERT density need to be considered in future clinical studies.

Adolescent↗
PubMed2003

The prefrontal cortex: insights from functional neuroimaging using cognitive activation tasks.

This review presents neuroimaging studies which have explored the functional anatomy of a variety of cognitive processes represented by the prefrontal cortex (PFC). Overall, these studies have demonstrated that standard prefrontal neuroactivation tasks recruit a widely distributed network within the brain of which the PFC consistently forms a part. As such, these results are in keeping with the notion that executive functions within the PFC rely not only on anterior (mainly prefrontal) brain areas, but also on posterior (mainly parietal) brain regions. Moreover, intervention of similar brain regions in a large number of different executive tasks suggests that higher-level cognitive functions may best be understood in terms of an interactive network of specialised anterior as well as posterior brain regions.

Animals↗
PubMed2002

Neuroimaging of thalamic tumors in children.

INTRODUCTION: Thalamic tumors are typical deep brain tumors; their incidence is not precisely known because of the different definition criteria. However, taking only lesions arising in the thalami into consideration (and excluding those secondarily involving the thalami from adjacent structures) approximately 40% of thalamic tumors affect patients under 18 years of age and thalamic neoplasms account for 2-5% of all intracranial tumors in children. MATERIALS AND METHODS: In the present paper we have focused attention on the neuroimaging features of thalamic tumors in a pediatric population; based upon personal experience, we suggest a rational neuroradiological approach to the diagnostic evaluation, describe CT and MRI findings of the most common tumors, and attempt to define basic patterns in order to provide the most reliable "pathological" diagnosis.

Adolescent↗
PubMed2004

Separation of craniopagus twins in the era of modern neuroimaging, interventional neuroradiology, and frameless stereotaxy.

INTRODUCTION: Craniopagus twinning is a rare embryological event occurring in 1 in 2.5 million births. CASE REPORT: We present our recent experience with the separation of total vertical craniopagus twins in the modern era of neuroimaging and interventional neuroradiology. Three-dimensional CT images revealed the twins' heads were axially rotated 30 degrees. MRI showed deficient dura between the brains of the twins, and some sharing of parietal brain tissue. Cerebral angiography showed a dominant arterial circulation of one twin with unilateral middle cerebral artery (MCA) branches feeding the other twin. The twins shared a common superior sagittal sinus in its middle segment where a circular sinus was formed. Prior to surgery, endovascular separation of the twins' arterial and venous circulations was achieved in part using tantalum coils for the MCA feeders in one twin, and balloon occlusion of the anterior superior sagittal sinus of the other. Using the ISG wand intraoperatively, surgery proceeded stepwise and included the circumferential removal of bone and opening of the dura, separation of the twins' brains along leptomeningeal planes, and identification of the major draining veins from the superficial cerebral cortex. DISCUSSION: The separation of craniopagus twins demands a multidisciplinary team approach. Utilizing preoperative neuroendovascular techniques to occlude shared vascular anastomotic channels, complex total vertical craniopagus twins can now be successfully separated in a one-stage procedure.

Child, Preschool↗
PubMed2004

Sinus pericranii: from gross and neuroimaging findings to different pathophysiological changes.

CASE REPORTS: We report two girls with a typical presentation of sinus pericranii. Both patients received total excision of the subgaleal masses with complete obliteration of the communications to the intracranial portion. However, different gross appearances, neuroimaging findings and intraoperative findings were found. It took more time and attention to control the bleeding due to the large communication between the extracranial and intracranial components in the second case. DISCUSSION: Sinus pericranii is composed of abnormal extracranial vascular tissues that communicate directly with intracranial dural sinuses or veins. A review of the literature showed that 13 out of 31 patients with sinus pericranii had a high-flow pattern. Detailed physical examination and imaging studies to detect dilated scalp veins and a large bony defect should remind surgeons of the presence of large venous communications. Meticulous treatment of the large communication during surgery can avoid massive bleeding.

Child↗
PubMed2001

Frontotemporal dementia: clinical, neuroimaging, and molecular biological findings in 6 patients.

Establishing the diagnosis in patients with clinical signs and symptoms suggesting primary degenerative disease with marked frontal lobe involvement is difficult. Neuroimaging methods, in particular positron emission tomography (PET) with the tracer 18fluoro-2-deoxyglucose (FDG) and cerebrospinal fluid (CSF) examination of beta-amyloid and tau-protein levels may give additional information. We report five patients with clinical and radiological features of degenerative dementia with predominantly frontal involvement and one patient with primary progressive aphasia Diagnostic work-up included computed tomography (CT), magnetic resonance imaging (MRI), PET and tau-protein and beta-amyloid level determination in CSF. While neuropsychological performance varied among patients, CT and MRI demonstrated persistently frontal lobe involvement. PET revealed corresponding changes with frontal hypometabolism, but in addition, four patients (among them two with no corresponding temporal changes in CT or MRI) showed a decreased glucose uptake in the temporal cortices. CSF samples from five patients revealed elevated beta-amyloid 1-42 and tau levels in three and two patients, respectively. Reduced beta-amyloid 1-40 was found in two patients. We conclude that occurrence of clinical symptoms of frontotemporal dementia is accompanied by frontal hypometabolism regardless of additional clinical findings. The value of determination of beta-amyloid and tau protein levels remains to be determined.

Aged↗
PubMed1999

Early diagnosis of dementia: neuroimaging.

The use of neuroimaging is reviewed in the diagnosis of dementia, especially Alzheimer's disease (AD). Computed tomography (CT) may be used to exclude other causes of dementia than AD. The finding of cortical or subcortical atrophy on CT or magnetic resonance imaging (MRI) itself does not indicate AD. Hippocampal atrophy on CT/MRI provides a useful early marker, although further longitudinal and neuropathological study is required. CT- and MRI-based measurements of hippocampal atrophy show promise in providing useful diagnostic information for discriminating patients with probable AD from normal elderly individuals. Using a standardized imaging protocol, including some assessment of hippocampal atrophy, can save costs since patients with suspected AD must undergo a cross-sectional imaging study to exclude other (treatable) causes of dementia. Combining an assessment of hippocampal atrophy with cerebral blood flow measurements by single photon emission computed tomography is not warranted either from a clinical or from an economic point of view.

Aged↗
PubMed1999

Clinical and neuroimaging study of central nervous system in congenital myotonic dystrophy.

We present the clinical and neuroimaging findings of five patients (four males, one female; mean age 12 years) affected by congenital myotonic dystrophy and the correlation with their molecular genetic analysis. At birth all five presented severe muscular weakness and hypotonia, associated with feeding difficulties and respiratory distress. In the same patients, congenital clubfoot or more generalized arthrogryposis was also evident. Lymphocyte DNA was characterized in each by a CTG repeat longer than 1300 in the region of the myotonic dystrophy gene in chromosome 19. The patients' neurological condition was evaluated by clinical examination, intelligence tests, electroencephalography, and brain magnetic resonance imaging. All five suffered from some impairment of intellectual function (IQ ranged from 52 to 79). In three a longitudinal evaluation of the cognitive deficit detected no deterioration. In all patients magnetic resonance imaging showed some degree of ventricular dilatation, loosely correlated to the cognitive impairment; in three there was hypoplasia of the corpus callosum and in two mild abnormalities of supratentorial white matter. The relationship between the size of the CTG repeat expansion found in lymphocyte DNA and the cerebral abnormalities appeared inconsistent in this unusual myoencephalopathy of the newborn.

Adolescent↗