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PubMed2006

EFNS guideline on neuroimaging in acute stroke. Report of an EFNS task force.

Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965-2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient.

Humans↗
PubMed2006

EFNS guidelines on the use of neuroimaging in the management of multiple sclerosis.

Magnetic resonance (MR)-based techniques are widely used for the assessment of patients with suspected and definite multiple sclerosis (MS). However, despite the publication of several position papers, which attempted to define the utility of MR techniques in the management of MS, their application in everyday clinical practice is still suboptimal. This is probably related, not only, to the fact that the majority of published guidelines focused on the optimization of MR technology in clinical trials, but also to the continuing development of modern, quantitative MR-based techniques, that have not as yet entered the clinical arena. The present report summarizes the conclusions of the 'EFNS Expert Panel of Neuroimaging of MS' on the application of conventional and non-conventional MR techniques to the clinical management of patients with MS. These guidelines are intended to assist in the use of conventional MRI for the diagnosis and longitudinal monitoring of patients with MS. In addition, they should provide a foundation for the development of more widespread but rational clinical applications of non-conventional MR-based techniques in studies of MS patients.

Brain↗
PubMedDate not supplied

Transient focal abnormalities of neuroimaging studies during focal status epilepticus.

We report transient changes in computed tomography (CT) and magnetic resonance imaging (MRI) scans in a patient with focal status epilepticus, referred to us with a tentative diagnosis of neoplasm based on CT and angiographic findings. EEG seizures originated independently from each temporal-occipital area, predominantly from the right. Previous EEGs had shown almost exclusively right temporo-occipital epileptogenic activity. MRI showed increased signal intensity, and CT showed decreased right hemisphere attenuation without enhancement. One month later, there was resolution of the radiological and clinical abnormalities. The transient CT and MRI changes probably represented focal cerebral edema, developing during focal status epilepticus. Lack of change in the left hemisphere probably reflected the quantitative difference in epileptic activity. Clues to the diagnosis of focal edema due to status include: (1) changes on electrical and imaging studies that correlate anatomically with the clinical status, and (2) resolution of abnormalities with appropriate seizure control. In patients with suspected seizure disorders, electrical and clinical data should be correlated before interpretation is made of focal lesions seen by neuroimaging techniques.

Adult↗
PubMed1994

Commentary: how has neuroimaging improved patient care?

Neuroimaging has significantly altered the management of patients with partial epilepsy. Magnetic resonance imaging (MRI) has been demonstrated to be a reliable and accurate indicator of the common pathologic findings underlying a partial seizure disorder. Intracranial mass lesions have been shown to be highly coherent with the localization of the epileptogenic zone. An MRI-identified epileptogenic lesion affects the selection of patients for epilepsy surgery and alters the diagnostic evaluation and the operative strategy. The results of the MRI preoperatively have prognostic importance in patients undergoing surgical treatment for partial epilepsy. Patients with lesional epileptic syndromes are considered favorable candidates for surgical ablative treatment. Hippocampal volume studies may predict the neurocognitive outcome in patients undergoing temporal lobe surgery. The use of MRI has resulted in a reduction in chronic intracranial EEG monitoring at most epilepsy centers, especially in patients with lesional pathology. MRI may be a reasonable initial "screening" procedure in selected patients with intractable partial epilepsy before consideration of a presurgical evaluation. A classification of partial epilepsy is proposed, based on the results of MRI, that may be useful for patients being considered for surgical treatment. Importantly, preoperative MRI must be correlated with the electrophysiologic studies and ictal semiology before decision-making regarding surgical therapy.

Adult↗
PubMed1996

Neuroimaging in pediatric epilepsy.

Neuroimaging techniques have advanced the diagnosis, management, and understanding of the pathophysiology underlying the epilepsies. High-resolution ultrasound is an important and useful technique in the investigation of prematures and neonates with seizures. Computed tomography (CT) scans have a diminishing role in the investigation of patients with epilepsy, but in the absence of magnetic resonance imaging (MRI), CT may detect gross structural pathology. MRI is the technique of choice for investigation of patients with seizure disorders. MRI provides excellent anatomic information and tissue contrast, resulting in high sensitivity. MRI studies should be customized to answer the appropriate clinical question. Functional imaging techniques including single photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance spectroscopy, and functional MRI are becoming increasingly important in the investigation and management of patients with seizures. These techniques permit noninvasive assessment of the epileptic substrate, functional status, ictal activity, blood flow changes, metabolism, and neuroreceptors. Application of these new techniques promises to advance our understanding and treatment of seizures in children.

Adult↗
PubMed2002

Neuroimaging of acute cerebellitis.

Acute cerebellitis is one of the main causes of acute cerebellar dysfunction in childhood and may be infectious, postinfectious, or postvaccination. The etiology of acute cerebellitis is usually viral. Varicella zoster, Epsten-Barr, rubeola, pertussis, diphtheria, and coxsackie viruses are the most frequently involved agents. Diagnosing of acute cerebellitis can sometimes be difficult because the patient may present only mild cerebellar signs and the examination of cerebrospinal fluid may be normal. The authors present the clinical and neuroimaging findings of 2 patients presenting with acute cerebellitis. Their magnetic resonance imaging showed hyperintense signal of cerebellar gray matter in T2-weighted sequences, which is a strong indication of a diagnosis of acute cerebellitis.

Acute Disease↗
PubMed2006

Neuroimaging of focal cortical dysplasia.

Focal cortical dysplasia (FCD) is a common cause of pharmacoresistant epilepsy that is amenable to surgical resective treatment. The identification of structural FCD by magnetic resonance imaging (MRI) can contribute to the detection of the epileptogenic zone and improve the outcome of epilepsy surgery. MR epilepsy protocols that include specific T1 and T2 weighted, and fluid-attenuated inversion recovery (FLAIR) sequences give complementary information about the characteristic imaging features of FCD; focal cortical thickening, blurring of the gray-white junction, high FLAIR signal, and gyral anatomical abnormalities. Novel imaging techniques such as magnetic resonance spectroscopy (MRS), magnetization transfer imaging (MTI), and diffusion tensor imaging (DTI) can improve the sensitivity of MR to localize the anatomical lesion. Functional/metabolic techniques such as positron emission tomography (PET), ictal subtraction single photon emission computed tomography (SPECT), functional MRI (fMRI), and magnetic source imaging (MSI) have the potential to visualize the metabolic, vascular, and epileptogenic properties of the FCD lesion, respectively. Identification of eloquent areas of cortex, to assist in the surgical resection plan, can be obtained non-invasively through the use of fMRI and MSI. Although a significant number of FCD lesions remain unidentified using current neuroimaging techniques, future advances should result in the identification of an increasing number of these cortical malformations.

Cerebral Cortex↗
PubMed2006

Neuroimaging of tuberculous myelitis: analysis of ten cases and review of literature.

We retrospectively reviewed the clinical and neuroimaging features of 10 patients with tuberculous myelitis. The most common presenting symptoms were fever (70%) and paraplegia (60%). Bladder and bowel symptoms were present in 90% patients. On MRI, the involvement of the cervical/thoracic segment of the spinal cord was most commonly seen (90%). The most consistent finding was hyperintense signals on T2-weighted MRI. T1-weighted images showed isointense (n= 5) and hypointense (n= 4) signals in the spinal cord lesions. Post-contrast enhancement was present in 6 patients, epidural enhancement in 4 patients, and cord swelling in 2 patients. We reviewed more than 250 published cases with the diagnosis of tuberculous myelitis and radiculomyelitis with special attention to MRI findings. It is predominantly a disease of the thoracic spinal cord. Most spinal cord lesions appear as hyperintense on T2 and iso- or hypointense on T1-weighted images. MRI findings in patients with spinal cord tuberculosis have both diagnostic and prognostic significance. Cord atrophy or cavitation and the presence of syrinx on MRI may be associated with poor outcome.

Adolescent↗
PubMed1988

The role of neuroimaging in the surgical treatment of epilepsy.

Resective surgical treatment of medically intractable epilepsy requires accurate identification of the site and extent of the epileptogenic zone responsible for habitual seizures. Epileptogenicity per se is demonstrated electrophysiologically, but interictal and ictal EEG transients, whether recorded extracranially or intracranially, propagate widely and can give rise to false lateralizing and false localizing information. Neuroimaging techniques provide additional important information which greatly enhances confidence in localization derived electrophysiologically. Structural imaging with X-ray computed tomography and magnetic resonance imaging, as well as functional imaging with positron emission tomography, single photon emission computed tomography, and computerized mapping of electromagnetic activity, used together with other tests of focal functional deficit, 1) increase the confidence with which surgical resection can be performed on the basis of noninvasive tests alone, 2) aid in developing appropriate strategy for intracranial electrode recording when this is necessary, and 3) supplement results of invasive studies sufficiently to justify surgical resection in some patients who otherwise might be rejected for surgery. Addition of these new techniques, therefore, has increased the number of patients considered candidates for surgery, decreased the number of invasive procedures necessary before surgery can be performed, and increased the accuracy of surgical resection.

Brain↗
PubMed2005

Outcome 1 year after aneurysmal subarachnoid hemorrhage: relation between cognitive performance and neuroimaging.

OBJECTIVE: To assess the cognitive impairment and the association between neuropsychological measures and neuroimaging 1 year after aneurysmal subarachnoid hemorrhage (SAH). METHOD: Forty-two patients were examined clinically according to Glasgow Outcome Scale (GOS). Computed tomography (CT), single photon emission computed tomography (SPECT) and neuropsychological examination were performed. RESULTS: There were no association between GOS and cognitive impairment index based on the neuropsychological examination. CT showed no sign of cerebral ischemia in 17 (40%) and low attenuating areas indicating cerebral infarction(s) in 25 (60%) patients. A significant correlation (P = 0.01) was observed between the cognitive impairment index and the SPECT index (r = 0.6). SPECT measurement was the only independent predictor for cognitive impairment. CONCLUSION: GOS is a crude outcome measure and patients classified with good recoveries may have significant cognitive deficits. Neuropsychological examination is the preferred method for outcome evaluation as this method specifically addresses the disabilities affecting patients' everyday life.

Adult↗
PubMed1999

Auditory hallucinations: phenomenology, neuropsychology and neuroimaging update.

Auditory verbal hallucinations (AVHs) are a cardinal feature of psychosis. Recent research is reviewed which has attempted to advance our knowledge of the mechanisms underlying this symptom. Phenomenological surveys have confirmed the importance of the content of such hallucinations and their meaning to the voice-hearer. Psychological and neuroimaging studies of inner speech and source monitoring have provided a neuropsychological framework for AVHs as well as some novel therapeutic strategies. There have also been successful attempts to 'capture' neural activity coincident with the experience of hallucinations using PET, SPECT and functional magnetic resonance imaging (MRI). This body of knowledge in combination with work on in-vivo receptor binding (dopamine and GABA) provides the beginnings of a cognitive and neurophysiological understanding of this complex and intriguing phenomenon.

Auditory Cortex↗
PubMed1998

Understanding neural interactions in learning and memory using functional neuroimaging.

Neuroimaging methods such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) provide a unique opportunity to explore activity across the entire human brain in many different behaviors. An important additional feature is the ability to examine interacting neural systems using methods that focus on the covariances of activity. Two of these methods, partial least squares and structural equation modeling, are presented with specific examples. Shifting prefrontal and limbic interactions were observed in a working memory task for faces. In an episodic memory retrieval study, the activity of right prefrontal cortex was related to either memory search or successful retrieval depending on its interactions with other brain regions. This latter observation implies that regional activity must be evaluated within the neural context in which it occurs. The general hypothesis that learning and memory are emergent properties of network interactions is discussed, emphasizing that a region can play a different role across many functions and that role is governed by its interactions with anatomically related regions.

Animals↗
PubMed2003

Neuroimaging abnormalities in the amygdala in mood disorders.

Neuroimaging technology has been applied to investigate the pathophysiology of mood disorders in studies aimed at characterizing the anatomical correlates of depressive symptoms, the neurophysiological effects of antidepressant treatments, and the trait-like abnormalities that persist despite symptom remission. These studies have identified cerebral blood flow and metabolic differences between depressives and controls in the amygdala and anatomically related areas of the prefrontal cortex, striatum, and thalamus. Taken together with converging evidence from neuroendocrine, lesion analysis, and postmortem studies of clinically depressed subjects, these data suggest that emotional/stress-response systems that include the amygdala are pathologically activated in major depression and that this activity is associated with dysfunction of the prefrontal cortex and monoamine neurotransmitter systems that normally modulate such responses.

Affect↗
PubMed1997

Neuroimaging findings in Rasmussen's syndrome.

Rasmussen's syndrome is a progressive childhood disease of unknown cause characterized by severe epilepsy, hemiparesis, mental deterioration, inflammation of one cerebral hemisphere, and brain atrophy. Computed tomography, single-photon emission computed tomography (SPECT), and magnetic resonance (MR) neuroimaging findings of 8 patients with pathologically confirmed Rasmussen's syndrome were evaluated retrospectively. All patients showed a predominance of the atrophy in the temporoinsular region and cerebral hemispheric alterations on MR images in a similar extension as seen on SPECT studies. Focal increase in regional cerebral blood flow was observed in the 4 patients presenting with epilepsia partialis continua at the time of hexamethylpropyleneamineoxime injection. Extensive cortical hypoperfusion was noted in the other 4 patients who received the injection during the interictal state. Cerebellar functional abnormalities were present in 6 patients, 2 of them with structural damage.

Adolescent↗
PubMed1999

Neuroimaging findings in a patient recovering from global alexia to spelling dyslexia.

The authors report findings in a 67-year-old right-handed man who had an ischemic infarct in the territory of the left posterior cerebral artery. The clinical manifestation consisted mainly of total alexia without agraphia. The patient gradually recovered, subsequently showing the syndrome of spelling dyslexia. Cerebral MR-images revealed a circumscript infarction of medial and basal parts of left temporal lobe. In the acute stage [99mTc]HM-PAO SPECT was characterized by a diminished uptake in the definitely infarcted area and hyperfixation in the region of the left forceps major. Because high retention of HM-PAO indicates potentially salvageable tissue after an ischemic event, the depicted area might be correlated with the recovery of function. Thus, the authors' neuroimaging data give further support to the assumption that the left forceps major is a critical area for global alexia, whereas spelling dyslexia is due to involvement of the left medio-basal temporal lobe.

Aged↗
PubMed2000

Phakomatoses. Part I: Neurofibromatosis type 1: common and uncommon neuroimaging findings.

Neurofibromatosis type I (NF-1) belongs to a family of diseases named phakomatoses, which are characterized by congenital malformations of ectodermal structures. Neurofibromatosis type I affects 1 in 3000 people, and has a diverse clinical presentation as well as an array of imaging findings. In this article the authors review the various neuroimaging findings present in NF-1, including abnormalities of the parenchyma, meninges, vessels, and associated neoplasms.

Brain↗
PubMed2004

Effects of dopamine transporter inhibitors on cocaine self-administration in rhesus monkeys: relationship to transporter occupancy determined by positron emission tomography neuroimaging.

The dopamine transporter (DAT) is a critical recognition site for cocaine and contributes to its significant abuse liability. Accordingly, the development of compounds that target the DAT represents a logical approach in the pharmacological treatment of cocaine abuse. The present study characterized the effects of DAT inhibitors as pretreatments in rhesus monkeys trained to self-administer cocaine under a second-order schedule of i.v. drug delivery. The drugs also were substituted for cocaine to characterize their effectiveness in maintaining drug self-administration. Positron emission tomography neuroimaging with [(18)F]8-(2-[(18)F]fluoroethyl)-2beta-carbomethoxy-3beta-(4-chlorophenyl) nortropane established the DAT occupancy associated with behaviorally relevant doses of each drug. The drugs studied included a selective DAT inhibitor, [1-(2[bis(4-fluorophenyl-) methoxy]ethyl)-4-(3-phenylpropyl)piperazine] bimesylate hydrate (GBR 12909); an inhibitor with equal potency at dopamine and norepinephrine transporters, [3beta-(4-chlorophenyl)tropane-2beta-(3-phenylisoxazol-5-yl)] HCl (RTI-177); and a nonselective inhibitor of dopamine, norepinephrinem and serotonin transporters, [(-)-3beta-(3'-methyl-4-chlorophenyl)tropane-2beta-carboxylic acid methyl ester] tartrate (RTI-112). All drugs produced dose-related reductions in cocaine self-administration. Doses of GBR 12909 and RTI-177 that reduced responding by 50% (ED(50)) resulted in DAT occupancies of 67 +/- 5 and 73 +/- 5%, respectively. In contrast, DAT occupancy was below the limit of detection for the ED(50) dose of RTI-112. Both GBR 12909 and RTI-177 reliably maintained drug self-administration, and DAT occupancies at doses that maintained peak rates of responding were 57 +/- 1 and 92 +/- 7%, respectively. In contrast, RTI-112 failed to maintain robust drug self-administration in any subject. The results indicate that selective DAT inhibitors may require high DAT occupancy to reduce cocaine self-administration and maintain drug self-administration. Moreover, the behavioral profile of DAT inhibitors may be influenced by actions at other monoamine transporters.

Anesthesia↗
PubMed2005

Cognitive and neuroimaging findings in physically abused preschoolers.

AIMS: To characterise the cognitive, motor, and language skills of toddlers and preschoolers who had been physically abused and to obtain concurrent MRIs of the brain. METHODS: A between groups design was used to compare a sample of 19 children, aged 14-77 months, who had been hospitalised for physical abuse with no evidence of neurological injury to a comparison group of 19 children matched for age and socioeconomic status. Children underwent cognitive, language, and motor testing within three months of their discharge from the hospital. Caregivers of the injured children were interviewed and were asked to complete questionnaires to characterise the child's developmental level and behaviour just prior to the hospitalisation. RESULTS: Children who had been physically abused scored significantly lower than the comparison group on measures of cognitive functioning, motor skills, and language skills. The groups did not differ in child behaviour ratings completed by the caregivers. MRI of the brain was performed for 15 children in the physical abuse group; two were found to have significant cerebral atrophy. CONCLUSIONS: Children who have been physically abused are at high risk for delays in cognitive, motor, and language development. Standard of care for these children should include developmental testing as well as neuroimaging of the brain to detect occult brain injury.

Adaptation, Psychological↗