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Neuroimaging curriculum for neurology trainees: report from the Neuroimaging Section of the AAN.

Neuroimaging plays a major role in the evaluation of patients with neurological disorders. Surveys of neurologists have revealed that most rely on their own readings of images for patient management, and a majority believe that neurologists should be allowed to officially interpret and bill for scan reviews. The importance of neuroimaging training for neurology residents has been stressed by the Association of University Professors of Neurology. Although there is a desire to promote the neuroimaging education of neurologists, no curricula have existed previously. The Neuroimaging Section of the American Academy of Neurology (AAN) developed a task force of practicing neuroimagers to provide a neuroimaging curriculum for neurological trainees and training directors. The resulting curriculum is available on the Web sites of the AAN (http://www.aan.com) and the American Society of Neuroimaging (http://www.asnweb.org/education/curriculum.shtml) and will be updated as the need arises through evolving technology or breadth of applications. This curriculum should help in the design of neurology residency and fellowship programs and subspecialty pathways in which adequate neuroimaging education and training are desired for various reasons, including certification and the demonstration of competency and proficiency.

Curriculum↗

Neuroimaging in the evaluation of children and adolescents with intractable epilepsy: II. Neuroimaging and pediatric epilepsy surgery.

The costs of epilepsy encompass all aspects of life, including medical, educational, and psychosocial. Adults with intractable epilepsy who undergo epilepsy surgery and have seizure-free outcomes still have significant barriers in the attainment of improved quality of life. For this reason, there is increasing interest in the recognition of children and adolescents with intractable epilepsy who might be epilepsy surgery candidates. This is Part II of an article on the role of neuroimaging in the evaluation of children and adolescents with intractable epilepsy. Part I addressed the role of MRI in detecting the substrates of epilepsy (Pediatr Neurol 1997;17: 19-26); Part II elaborates on the selection process of pediatric patients who might benefit from epilepsy surgery. Although EEG remains the cornerstone of the evaluation process, MRI, SPECT, and PET can play a pivotal role in the identification of the underlying epileptogenic focus and minimize the need for invasive EEG monitoring. Magnetic resonance spectroscopy and magnetoencephalography are also innovative, noninvasive techniques which may aid in the localization of the epileptogenic focus. Functional MRI scans may soon replace invasive technologies in the identification of eloquent cortex that should not be a part of the surgical resection.

Adolescent↗

Neuroimaging findings of the development and resolution of solitary brainstem abscess: characteristics of neuroimagings in the early stage of brainstem abscess and importance of surgical management for brainstem abscess--case report.

A 64-year-old female presented with a solitary brainstem abscess. Magnetic resonance imaging and computed tomography demonstrated the development and resolution of the brainstem abscess with an unusual and fluctuating clinical course over several months. Serial neuroimaging examinations are required to detect a brainstem abscess in the early stage to establish the optimum treatment.

Brain Abscess↗

Evaluation of reconstruction algorithms in SPECT neuroimaging: I. Comparison of statistical noise in SPECT neuroimages with 'naive' and 'realistic' predictions.

In the presence of statistical noise, an iterative reconstruction algorithm (IRA) for the quantitative reconstruction of single-photon-emission computed tomographic (SPECT) brain images overcomes major limitations of applying the standard filtered back projection (FBP) reconstruction algorithm to projection data which have been degraded by convolution of the true radioactivity distribution with a finite-resolution distance-dependent detector response: (a) the non-uniformity within the grey (or white) matter voxels which results even though the true model is uniform within these voxels; (b) a significantly lower ratio of grey/white matter voxel values than in the true model; and (c) an inability to detect an altered radioactivity value within the grey (or white) matter voxels. It is normally expected that an algorithm which improves spatial resolution and quantitative accuracy might also increase the magnitude of the statistical noise in the reconstructed image. However, the noise properties in the IRA images are very similar to those in the FBP images. In fact, the noise magnitude in both the FBP and IRA images is only slightly greater than that computed by the 'naive prediction', which presumably is a lower limit to the amount of statistical noise in a reconstructed image. Thus, the IRA should provide the potential for quantitative SPECT imaging of normal physiological responses or diseases involving both the brain grey and white matter.

Algorithms↗

The role of emergent neuroimaging in children with new-onset afebrile seizures.

OBJECTIVES: The objectives of this study were 1) to determine the frequency of clinically significant abnormal neuroimaging in children coming to the emergency department (ED) with new-onset afebrile seizures (ASZ), and 2) to identify children at high or low risk for clinically significant abnormal neuroimaging. DESIGN/METHODS: Five hundred consecutive cases of new-onset ASZ seen in the ED of a tertiary care children's hospital were reviewed. Neuroimaging reports were categorized as normal, clinically insignificant abnormal, or clinically significant abnormal. Recursive partition analysis was used to identify clinical variables that separated children into high- and low-risk groups for clinically significant abnormal neuroimaging. RESULTS: Ninety-five percent of patients (475/500) with new-onset ASZ had neuroimaging. Clinically significant abnormal neuroimaging was noted in 8% (95% confidence interval [CI]: 6, 11; 38/475) of patients. Recursive partition analysis identified 2 criteria associated with high risk for clinically significant abnormal neuroimaging: 1) the presence of a predisposing condition, and 2) focal seizure if <33 months old. Of the high-risk patients, 26% (95% CI: 17, 35; 32/121) had clinically significant abnormal neuroimaging compared with 2% (95% CI: 0.6, 3.7; 6/354) in the low-risk group. CONCLUSIONS: In this large, retrospective review of children with new-onset ASZ, clinically significant abnormal neuroimaging occurred with relatively low frequency. Emergent neuroimaging should be considered, however, for children who meet high-risk criteria. Well-appearing children who meet low-risk criteria can be safely discharged from the ED (if follow-up can be assured) without emergent neuroimaging, because their risk for clinically significant abnormal neuroimaging is appreciably lower.

Adolescent↗

Is it worth pursuing surgery for epilepsy in patients with normal neuroimaging?

OBJECTIVE: To determine whether it is worth pursuing surgery for the treatment of epilepsy in patients with normal neuroimaging. METHODS: Two patient populations were studied: (1) 136 consecutive patients who were surgically treated; (2) 105 consecutive patients assessed with chronically implanted intracranial electrodes within the same period. Sixty patients belonged to both groups, and included all 21 patients who had normal neuroimaging. RESULTS: There were no differences in the proportion of patients with favourable outcome between those with normal and those with abnormal neuroimaging, irrespective of whether intracranial recordings were required. Among the 19 operated patients with normal neuroimaging, 74% had a favourable outcome (Engel's seizure outcome grades I and II), and among the 93 patients with abnormal neuroimaging, 73% had favourable outcome (p = 0.96). In patients with temporal resections, 92% of the 13 patients with normal neuroimaging had a favourable outcome, whereas among the 70 patients with abnormal neuroimaging, 80% had a favourable outcome (p = 0.44). In patients with extratemporal resections, two of the six patients with normal neuroimaging had a favourable outcome, while 12 of the 23 patients with abnormal neuroimaging had a favourable outcome (p = 0.65). Among the 105 patients studied with intracranial electrodes, five suffered transitory deficits as a result of implantation, and two suffered permanent deficits (one hemiplegia caused by haematoma and one mild dysphasia resulting from haemorrhage). CONCLUSIONS: It is worth pursuing surgery in patients with normal neuroimaging because it results in good seizure control and the incidence of permanent deficits associated with intracranial studies is low.

Adolescent↗

[Reasons for requesting neuroimaging studies in the evaluation of primary headache].

INTRODUCTION: There is some controversy concerning the need to perform neuroimaging studies in patient complaining of headache. 90% of the people had a complaint of headache during their life, and it is impossible to perform neuroimaging studies in all of them. OBJECTIVE: The aim of this study is knowing the reasons for indications neuroimaging studies in the evaluation of primary headaches and the effectiveness at the diagnosis. PATIENTS AND METHODS: The clinical records of patients who a neuroimaging study was performed for headache during 1998 were retrospectively studied. We analysed in all patients: the age, sex, diagnosis of headache, suspicion of diagnosis, reason and time for indication the neuroimaging study, and if the study modified the diagnosis. RESULTS: During 1998, were performed 107 neuroimaging studies in 96 patients. The mean age were 38 years. 60% were females. The suspicion of diagnosis was primary headache in 71% patients. Only one patient had an abnormality. The reasons for applying a neuroimaging study were: in 20 of the patients the migraine was more frequent and they didn t relieve with abortive drugs, in 20 there was a migraine aura, in 11 because the migraine turned to daily headache, in 17 the family asked for a neuroimaging study, there was a 17 of patients seemed to have an organic disease, in 2 the headache appeared daily, and in 7 of the cases weren't any reasons. CONCLUSIONS: Headache is the most frequent reason for asking a neuroimaging study. Primary headache is the type of headache that justifies most of indications. The most frequent reasons for performing a study were common changes in characteristics of migraine.

Adolescent↗

Bidirectional causal relationships between plasma proteins, neuroimaging metrics and risk of Alzheimer's disease.

BACKGROUND: Changes in neuroimaging metrics are among the first detectable pathophysiological alterations in Alzheimer's disease (AD). Proteins are closely linked to fluctuations in neuroimaging metrics. Therefore, the analysis of the proteomic signature associated with neuroimaging metrics holds significant promise for uncovering therapeutic targets that contribute to AD. METHODS: GWAS data concerning the Brain Imaging Data Structure (BIDs). The AD cohort comprised a total of 401,661 individuals diagnosed with AD, alongside 10,520 control participants. For a bidirectional MR analysis involving neuroimaging metrics, proteomics, and AD, the methods utilized included inverse variance weighted (IVW), MR Egger, weighted median, weighted mode, and the Wald ratio approaches. RESULTS: We identified 12 neuroimaging metrics that demonstrate significant relevance to AD (thickness of the left total hemisphere, volume of the right thalamus, and et al.). These metrics are structural magnetic resonance imaging (MRI) biomarkers that remain stable throughout the entire course of AD, from the preclinical stage through mild cognitive impairment (MCI) to dementia. Additionally, we found a substantial number of 1633 proteins that also show a noteworthy causal relationship with AD. Functional enrichment analysis indicated that these proteins were predominantly focused within various pathways linked to AD, encompassing those involved in the synaptic vesicle cycle, synaptic membranes, neurotransmitter release, and the activity of GABA receptors. In addition, our research indicates that the significant relationships observed between the identified proteins and AD are influenced by neuroimaging metrics. Notably, we found that these neuroimaging metrics play a crucial role in mediating a substantial 67% of the inverse relationship that exists between PTPRC and the phenotypic characteristics associated with AD. CONCLUSIONS: This study successfully establishes a connection between proteomic and neuroimaging metrics, as well as the AD that influence them. By creating this relationship, the research offers important information that aids in comprehending the intricate mechanisms involved in AD.

Alzheimer Disease↗

A critical discussion of the role of neuroimaging in mild cognitive impairment.

OBJECTIVE: In this paper, the current neuroimaging literature is reviewed with regard to characteristic findings in mild cognitive impairment (MCI). Particular attention is drawn to the possible value of neuroimaging modalities in the prediction and early diagnosis of Alzheimer's disease (AD). METHODS: First, the potential contribution of neuroimaging to an early, preclinical diagnosis of degenerative disorders is discussed at the background of our knowledge about the pathogenesis of AD. Second, relevant neuroimaging studies focusing on MCI are explored and summarized. Neuroimaging studies were found through Medline search and by systematically checking through the bibliographies of relevant articles. RESULTS: Structural volumetric magnetic resonance imaging (MRI) and positron emission tomography (PET)/single photon emission tomography (SPECT) are currently the most commonly used neuroimaging modalities in studies focusing on MCI. There were considerable variations in demographical and clinical characteristics across studies. However, significant hippocampal and entorhinal cortex volume reductions were consistently found in subjects with MCI as compared with cognitively unimpaired controls. While hippocampal and entorhinal cortex atrophy in subjects with MCI are also well-established risk factors for the development of AD, these measures cannot be regarded as being of high predictive value in an individual case. Evidence for other typical neuroimaging changes in MCI is still scarce. In PET and SPECT studies, reduced blood flow and/or glucose metabolism in temporoparietal association areas, posterior cingulate and hippocampus were associated with a higher risk of progressive cognitive decline in MCI. In quantitative electroencephalogram (QEEG), low beta, high theta, low alpha and slowed mean frequency were associated with development of dementia. CONCLUSIONS: Existing studies suggest that neuroimaging measures have the potential to become valuable tools in the early diagnosis of AD. To establish their value in routine use, larger studies, preferably with long prospective follow-up are needed.

Alzheimer Disease↗