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PubMedDate not supplied

Mimics of brain tumor on neuroimaging: part I.

Brain tumor is a distinct pathological entity that differs from other diseases, including cerebrovascular, demyelinating, inflammatory, infectious, and various miscellaneous diseases. Insidious onset and gradual progression of signs and symptoms are common in patients with brain tumors, whereas the onset of cerebrovascular diseases is usually acute or sudden. Patients with demyelinating, inflammatory, or infectious diseases show subacute onset. Differentiation of brain tumors from other disorders is usually possible from the clinically and radiologically characteristic features. However, in some diseases other than brain tumors, an atypical clinical course and/or radiological findings may suggest or simulate those of brain tumors. The diagnosis of brain tumor is confirmed histopathologically, and appropriate therapies are given to the patient based on the histopathological type and grade of the tumor. In order to obtain a specimen for histopathological examination, surgical intervention is required. Other diseases are usually diagnosed clinically and radiologically. Invasive procedures should be avoided in making a diagnosis. Therefore, differentiation of brain tumors from other diseases is a critical issue for neuroimaging. Detailed inspection of images is necessary, and characteristic findings, and additional imaging methods, such as diffusion-weighted imaging, are often helpful for the differential diagnosis. We assess the imaging findings of diseases simulating brain tumors and review the literature.

Adult↗
PubMedDate not supplied

Mimics of brain tumor on neuroimaging: part II.

Brain tumor is a distinct pathological entity that differs from other diseases, including cerebrovascular, demyelinating, inflammatory, infectious, and various miscellaneous diseases. Insidious onset and gradual progression of signs and symptoms are common in patients with brain tumors, whereas the onset of cerebrovascular diseases is usually acute or sudden. Patients with demyelinating, inflammatory, or infectious diseases show subacute onset. Differentiation of brain tumors from other disorders is usually possible from the clinically and radiologically characteristic features. However, in some diseases other than brain tumors, an atypical clinical course and/or radiological findings may suggest or simulate those of brain tumors. The diagnosis of brain tumor is confirmed histopathologically, and appropriate therapies are given to the patient based on the histopathological type and grade of the tumor. In order to obtain a specimen for histopathological examination, surgical intervention is required. Other diseases are usually diagnosed clinically and radiologically. Invasive procedures should be avoided in making a diagnosis. Therefore, differentiation of brain tumors from other diseases is a critical issue for neuroimaging. Detailed inspection of images is necessary, and characteristic findings, and additional imaging methods, such as diffusion-weighted imaging, are often helpful for the differential diagnosis. We assess the imaging findings of diseases simulating brain tumors and review the literature.

Brain Neoplasms↗
PubMed2004

A role for sleep in the processing of memory traces. Contribution of functional neuroimaging in humans.

Sleep is thought to participate in the consolidation of recent memory traces. We tested this hypothesis in humans, using functional neuroimaging (functional magnetic resonance imaging and positron emission tomography). First, following the training on a procedural visuo-motor learning task (pursuit task), total sleep deprivation on the first post-training night significantly deteriorates the gain in performance, which is usually observed after one complete night of sleep. In parallel, sleep deprivation hampers the changes in functional segregation and connectivity, which underpin the gain in performance usually observed in subjects allowed to sleep on the first post-training night. Second, following the training on an implicit memory task (probabilistic serial reaction time task), some brain areas are reactivated during REM sleep on the first post-training night. The reactivation was shown to be related to the processing of high-level material and to be modulated by the amount of learning achieved during the training session. These changes in activity do not involve isolated brain areas but entire macroscopic cortico-subcortical networks. Taken together, the results suggest an off-line processing of recent memory traces during sleep.

Brain↗
PubMed2005

[Clinical, neuroimaging and electroencephalographic findings of encephalopathy occuring after the ingestion of "sugihiratake" (Pleurocybella porrigens), an autumn mashroom: a report of two cases].

We report a 54-year-old man (case 1) and a 79-year-old woman (case 2) who presented with encephalopathy of unknown cause. Both patients were on hemodyalysis and took an autumn mashroom, "sugihiratake" (Pleurocybella porrigens), two to three weeks prior to the onset of neurological alterations. The clinical syndrome of those patients was characterized by weakness and involuntary movements of the extremities (cases 1 and 2) or dysarthria (case 1) at the onset of the disease and subsequent intractable focal motor seizures, resulting in generalized status epilepticus or comatose state, six (case 1) or three (case 2) days after the disease onset. Epileptic seizures were gradually improved in both cases. On brain MRI of case 1, no relevant lesions were detectable at the onset day, but, 6 days after onset, T2-high intensity lesions were noted in the subcortical white matter of the insular cortex, claustrum, external capsule, putamen and globus pallidus on both sides. On brain CT scan of case 2, there were no apparent lesions at the onset day, but, 4 days after onset, low density areas were noted bilaterally in the subcortical white matter of the insular cortex. Electroencephalography of the two patients taken on a day of comatose state showed periodic synchronous discharge (PSD), which disappeared when their consciousness levels were improved. As far as we have examined, there was no findings to suggest the cause of the encephalopathy in routine laboratory examinations and various viral antibody studies of the blood and cerebrospinal fluid. The reported patients could constitute a newly recognized disease entity, "sugihiratake" encephalopathy. Our observations suggest that it can be an encephalopathy with subacute progression and affect mainly the basal ganglia. Neuroimaging study and electroencephalographic findings may help the diagnosis, although they may remain unremarkable for several days after onset of the neurological alterations.

Aged↗
PubMed2005

Cognitive avionics and watching spaceflight crews think: generation-after-next research tools in functional neuroimaging.

Confinement and isolation have always confounded the extraordinary endeavor of human spaceflight. Psychosocial health is at the forefront in considering risk factors that imperil missions of 1- to 2-yr duration. Current crewmember selection metrics restricted to behavioral observation by definition observe rather than prevent performance degradation and are thus inadequate when preflight training cannot simulate an entire journey. Nascent techniques to monitor functional and task-related cortical neural activity show promise and can be extended to include whole-brain monitoring. Watching spaceflight crews think can reveal the efficiency of training procedures. Moreover, observing subcortical emotion centers may provide early detection of developing neuropsychiatric disorders. The non-invasive functional neuroimaging modalities electroencephalography (EEG), magnetoencephalography (MEG), magnetic resonance imaging (MRI), and near-infrared spectroscopy (NIRS), and highlights of how they may be engineered for spacecraft are detailed. Preflight and in-flight applications to crewmember behavioral health from current generation, next generation, and generation-after-next neuroscience research studies are also described. The emphasis is on preventing the onset of neuropsychiatric dysfunctions, thus reducing the risk of mission failure due to human error.

Aerospace Medicine↗
PubMedDate not supplied

Phase-sensitive T1 inversion recovery imaging: a time-efficient interleaved technique for improved tissue contrast in neuroimaging.

BACKGROUND AND PURPOSE: High tissue contrast and short acquisition time are desirable when scanning patients. The purpose of this report is to describe the implementation of a new technique for generating high gray matter (GM) and white matter (WM) contrast in a short scan time, make a quantitative evaluation of the contrast efficiency, and explore its potential applications in neuroimaging. METHOD: A fully interleaved T1-weighted inversion recovery (T1IR) sequence with phase-sensitive reconstruction (PS-T1IR) is implemented. This sequence is compared with conventional T1-weighted spin-echo imaging (T1SE) and T1-weighted fluid-attenuated inversion recovery (T1FLAIR). The time efficiency and contrast enhancement have been quantitatively analyzed in normal volunteers. The performance of the sequence is evaluated in >30 patients with neurologic disorders. The sensitivity of PS-T1IR relative to T1SE in detecting gadolinium enhancements is also evaluated. RESULTS: PS-T1IR is more time-efficient than T1SE and generates better GM-WM contrast. It results in the best contrast-to-noise ratio (CNR) efficiency (1.16) compared with T1FLAIR (0.73) and T1SE (0.23). For a typical clinical protocol, PS-T1IR takes only 1:30 minutes versus 2:40 minutes for T1SE imaging for the whole brain coverage. Although gadolinium enhancements are detected with comparable sensitivity on both PS-T1IR and T1SE sequences, in certain instances, the latter sequence appears to be more sensitive in demonstrating gadolinium enhancements within WM. CONCLUSION: PS-T1IR has the highest CNR efficiency compared with T1FLAIR and T1SE. It is a very practical technique for neuroradiologic applications.

Brain Diseases↗
PubMedDate not supplied

Neuropsychological tests and functional nuclear neuroimaging provide evidence of subclinical impairment in Nasu-Hakola disease heterozygotes.

Nasu-Hakola disease is a rare, recessively inherited disease characterized by presenile dementia and bone cysts. Until now, no evidence of subclincal pathological changes in individuals heterozygous for the mutations underlying Nasu-Hakola disease has been reported. We performed a functional neuroimaging (99mTc-ECD SPECT) and neuropsychological study of healthy members of an Italian family carrying a mutation in the TREM2 gene. Two healthy subjects heterozygous for one mutated TREM2 allele showed a deficit of visuospatial memory associated with hypoperfusion in the basal ganglia, whereas the homozygotes for the wild-type allele of TREM2 did not show any abnormalities.

Adult↗
PubMedDate not supplied

Emotional auditory paradigm in neuroimaging: a base for the study of psychosis.

INTRODUCTION: Since the arrival of neuroimaging numerous studies have tried to analyze the differences between emotional and non-emotional response. The majority of these studies use visual approach (faces) and begin with data in normal subjects. The present study introduces a new paradigm for the study of emotional response based on auditory approach and designed specifically for the study of psychoses. METHOD: The most frequent words heard by psychotic patients with auditory hallucinations were analyzed. They were classified according to five categories which were compared with 13 other words with the same structure but with a neutral emotional valency. This paradigm was applied to see the cerebral activation with functional magnetic resonance imaging (fMRI) in 10 right handed healthy males. RESULTS: In the preliminary analysis a clear differentiation is observed depending on the type of stimulus applied (emotional or non-emotional), both in the intensity of activation (right and left temporal cortex) as in the activation of specific areas (right precentral and supramarginal gyrus) only with the emotional stimulus. CONCLUSIONS: The present paradigm allows the observation of a differentiation in the cerebral activation to emotional auditory stimulus and could be of utility in the study of psychotic patients.

Affect↗
PubMed2004

Neuroimaging of epilepsy: advances and practical applications.

The role of modern neuroimaging in the management and treatment of patients with seizures and epilepsy continues to expand at a rapid pace. Magnetic resonance imaging (MRI) is now well established as the imaging technique of choice for patients with epilepsy, but new MR-based techniques, such as MR spectroscopy, functional (f)MRI, and fMRI/electroencephalogram, are more frequently being used to increase the yield of MRI in detecting abnormalities associated with epilepsy. In parallel, advances in radioactive-based techniques, such as single photon emission computed tomography, positron emission tomography, and magnetic source imaging, are improving the localization power of these techniques in candidates for epilepsy surgery. Advances in computer power are making possible the co-egistration in space of structural and functional information, thus improving the yield for the detection of lesions associated with epilepsy.

Brain↗
PubMed2006

Status epilepticus in a patient with fragile X syndrome: electro-clinical features and peri-ictal neuroimaging.

Fragile X syndrome (Fra-X) is a common cause of mental retardation that can be associated with partial epilepsy characterized by a variety of electro-clinical features. A wide spectrum of interictal activities are reported, although no data regarding ictal EEG activity have as yet been published. Drug-resistant seizures are uncommon, and the occurrence of clustering seizures or status epilepticus has only been reported anecdotally. We describe a Fra-X patient with refractory partial epilepsy related to a malformation of cortical development who experienced a partial status epilepticus that was well documented by video-EEG and MRI. We report the electro-clinical features and peri-ictal neuroimaging data.

Adolescent↗
PubMed2006

[Neuroimaging in the diagnosis of human transmissible spongiform encephalopathies].

INTRODUCTION: The role of neuroimaging in the diagnosis of the Human Transmissible Spongiform Encephalopathies (HTSE) has been changing from the exclusion of other conditions to the contribution of diagnostic data having incalculable utility, such as basal ganglia and cerebral cortex in different magnetic resonance imaging (MRI) sequences. METHODS: Search in Medline. Reading and analysis of related papers. RESULTS: There are alterations such as increased of the signals in the caudate nucleus, putamen and cerebral cortex in the sporadic Creutzfeldt-Jakob disease (CJD) or increased signal intensity in the pulvinar for the variant Creutzfeldt-Jakob disease (vCJD). These signals are associated with the molecular subtype in sporadic cases, stage and duration of the disease and with pathological findings. CONCLUSIONS: Although magnetic resonance imaging (MRI) is only currently included in the vCJD diagnostic criteria, it is a useful diagnostic test in the diagnosis of other HTSE, especially diffusion-weighted and FLAIR images.

14-3-3 Proteins↗
PubMedDate not supplied

Neuroimaging: a story of physicians and basic scientists.

Until just a few decades ago, it was very difficult to detect, non invasively, physiological signals from the brain. However, the discoveries in physics, the evolution of information technology, and the invention of non-invasive biomedical technologies in the last decades of the twentieth century transformed this scenario and created numerous opportunities for studying the brain in living subjects. The authors trace the extraordinary evolution of brain imaging techniques (magnetic resonance imaging, emission tomography, and ?functional neuroimaging?) in the second part of the twentieth century. Not only have these methods had a remarkable clinical impact, they have also been outstanding research tools in the field of the neurosciences. In their most recent applications, they are employed in the quest to uncover the neuronal substrate of the human mind.

Brain↗
PubMedDate not supplied

Discrepancy between neuroimaging findings and clinical phenotype in Alexander disease.

We present a case of infantile-onset Alexander disease (AD) with a novel glial fibrillary acidic protein mutation but without clinical evidence of neurologic deterioration. Brain MRI studies showed typical AD findings and increasing size of frontal cavitations. Serial proton MR spectroscopy demonstrated high levels of myo-inositol and lactic acid and decreasing levels of N-acetylaspartate. The degree of demyelination and the timing of the axonal degeneration may determine phenotypic severity of the disease. Conventional neuroimaging techniques cannot always predict the outcome.

Alexander Disease↗
PubMed2006

Malformations of cortical development in children: clinical manifestation, neuroimaging and neuropathology in selected cases.

Cerebral cortical development can be divided into three steps: cellular proliferation, neuronal migration and organization. Based on known pathologic, genetic and neuroimaging features a classification for malformations of cortical development was proposed by Barkovich in 2001, and updated in 2005. Malformations of cerebral cortex development (MCCD) often demonstrate epileptic seizures and delay in psychomotor development. About 20-40% of children with epilepsy are drug-resistant and there is a large paediatric population requiring epilepsy surgery operations. In our work we performed clinical analysis of 68 children with MCCD treated in our hospital between 2000 and 2006. In our work to consider the type of MCCD we used the updated classification scheme proposed by Barkovich et al. We analyzed epilepsy, gestational and perinatal history, initial symptoms, time to establishing full diagnosis and neurodevelopmental/IQ status. In our results we found that despite similar clinical manifestation neuropathological basis could be significantly different, and vice versa: children with nearly identical neuropathological findings could have completely different neurological and radiological symptoms. Children with drug-resistant epilepsy are potential candidates for neurosurgical treatment; especially lesionectomies in such cases could be very promising in terms of epilepsy management and quality of life as well.

Anticonvulsants↗
PubMed2006

Cerebral childhood and adolescent X-linked adrenoleukodystrophy. Clinical presentation, neurophysiological, neuroimaging and biochemical investigations.

Clinical, neurophysiological, neuroimaging and biochemical studies were performed in five boys with childhood and adolescent form of cerebral X-ALD, which is a very rare disease in developmental age. In all patients, rapidly progressive spasticity, ataxia and mental deterioration were found. Seizures occurred in four of them. Additionally, visual and hearing impairment were observed in four and three patients respectively. Adrenal insufficiency was also diagnosed in four cases. MR revealed extensive demyelination located mainly symmetrically in the parieto-occipital areas, in one patient in whom asymmetrical lesions in that region were found. All patients had abnormal visual, brainstem and somatosensory evoked potentials recording, reflecting the central demyelination occurring in X-ALD. The clinical diagnosis in every case was confirmed by the significantly elevated concentration of very long chain fatty acids (VLCFA) measured in plasma in comparison to normal values.

Adolescent↗
PubMedDate not supplied

Neuroimaging of acoustic nerve sheath tumors after stereotaxic radiosurgery.

Using a strict method for measuring tumor size, we evaluated tumor response to radiosurgery in 88 patients with 89 acoustic tumors treated over 3 years with a 201-source cobalt-60 gamma unit. Overall, tumor size was unchanged in 73% of patients and increased in 4%. In 22% of patients, tumor diameter decreased an average of 4.9 mm 3-33 months after treatment. Tumor shrinkage occurred in 36% of 50 patients who were followed for at least 1 year after treatment. Loss of tumor contrast enhancement was seen in 79% of patients 1-18 months after treatment. Delayed communicating hydrocephalus developed in four patients. In eight patients, increased signal on T2-weighted MR images developed in the adjacent cerebellar peduncle (n = 5) or the peduncle and dorsolateral pons (n = 3) 5-15 months after treatment. T1-weighted MR imaging and CT were insensitive to these adjacent brain changes. Stereotaxic radiosurgery is an important alternative treatment for selected patients with acoustic tumors. There is no mortality or major perioperative morbidity, hospitalization time and costs are smaller than for microsurgery, patient employment or functional level is maintained, and hearing preservation and facial neuropathy rates are comparable to those in published microsurgical series. Although the rate of occurrence of trigeminal neuropathy is greater than those reported in published microsurgical series, the majority of cases are mild, transient, and nondebilitating. MR imaging before and after radiosurgery is the most sensitive imaging tool to evaluate tumor response, the presence of adjacent parenchymal signal changes, and ventricular size. With a mean follow-up time of 14.6 months, the rate of complications detected by neuroimaging is low and the tumor control rate is 96%.

Adolescent↗
PubMed1991

Neuroimaging of AIDS.

A retrospective review of the neuroimaging procedures of 84 patients with the diagnosis of AIDS was performed. Both computed tomography (CT) and magnetic resonance imaging (MRI) procedures were evaluated for the presence of atrophy, enhancing lesions and focal non-enhancing lesions. The imaging findings in several infectious conditions (toxoplasmosis, cytomegalovirus, papovavirus, HIV virus, tuberculosis and histoplasmosis) are described. Intracranial lymphoma, another complication of AIDS, also is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Neuroimaging for central nervous system tumors.

Advances in neuroimaging techniques have now provided clinicians with the ability to detect CNS neoplasms at an earlier stage and to measure responses to therapy. However, errors in performing or interpreting these studies can lead to erroneous conclusions that may subsequently influence therapeutic decisions. The exact delineation of areas of tumor involvement in the brain has improved with newer imaging techniques, but this too is problematic in some patients. Evaluations of response to treatment can also be complicated by technical artifacts that can lead to inadequate differentiation of tumor from non-neoplastic tissues. Nevertheless, MRI and CT have helped clinicians to redefine the natural history of CNS tumors, reach earlier diagnoses, improve the accuracy of radiotherapy, explain adverse treatment responses, and exclude conditions that are not related directly to the tumor but that can be responsible for clinical deterioration. Newer tests that have the ability to assess tumor metabolism will further increase our understanding of these pathological processes.

Brain Neoplasms↗