Abstract: Some patients with unilateral medial temporal lobe epilepsy (MTLE) display bilateral hippocampal atrophy on MRI, even though seizures originate in only one hippocampus. The correct identification of the epileptogenic hippocampus (the 'generator') vs the non-epileptogenic (the 'receiver') may lead to better surgical planning and results.
Abstract: Background It has been hypothesised that seizure induced neuronal loss and axonal damage in medial temporal lobe epilepsy (MTLE) may lead to the development of aberrant connections between limbic structures and eventually result in the reorganisation of the limbic network. In this study, limbic structural connectivity in patients with MTLE was investigated, using diffusion tensor MRI, probabilistic tractography and graph theory based network analysis. Methods 12 patients with unilateral MTLE and hippocampal sclerosis (five left and seven right MTLE) and 26 healthy controls were studied. The connectivity of 10 bilateral limbic regions of interest was mapped with probabilistic tractography, and the probabilistic fibre density between each pair of regions was used as the measure of their weighted structural connectivity. Binary connectivity matrices were then obtained from the weighted connectivity matrix using a range of fixed density thresholds. Graph theory based properties of nodes (degree, local efficiency, clustering coefficient and betweenness centrality) and the network (global efficiency and average clustering coefficient) were calculated from the weight and binary connectivity matrices of each subject and compared between patients and controls. Results MTLE was associated with a regional reduction in fibre density compared with controls. Paradoxically, patients exhibited (1) increased limbic network clustering and (2) increased nodal efficiency, degree and clustering coefficient in the ipsilateral insula, superior temporal region and thalamus. There was also a significant reduction in clustering coefficient and efficiency of the ipsilateral hippocampus, accompanied by increased nodal degree. Conclusions These results suggest that MTLE is associated with reorganisation of the limbic system. These results corroborate the concept of MTLE as a network disease, and may contribute to the understanding of network excitability dynamics in epilepsy and MTLE.
Abstract: Previous studies using hierarchical figures (where a large global shape is composed of a series of smaller local shapes) suggest that performance is better for local features presented in the right relative to left visual field, whereas the opposite pattern is observed for global features. However, these previous studies have focused on effects between hemifields. Recent data from patients with neurological damage suggest that local deficits can be allocentric (e.g., following left hemisphere injury, individuals are relatively slow to detect features on the right side of an object, regardless of visual field). Therefore, we decided to extend previous global versus local research by also observing local performance within hemifields. Specifically, on each trial we presented two hierarchical figures (one in each hemifield), but crucially the left and right side of each item were composed of different local features. In this task, the participant simply reports if a circle is present, regardless of location or whether this is a local or global feature. We observed that both neurologically healthy individuals, as well as an individual with brain injury, were relatively better detecting local information on the right side of objects, regardless of spatial location, while both showed better performance for global stimuli in the left visual field. This work is consistent with recent work in patients with neurological damage, and provides a new paradigm for exploring hemispheric specialization.
Abstract: Surgical resection of the hippocampus is the most successful treatment for medication-refractory medial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis. Unfortunately, at least one of four operated patients continue to have disabling seizures after surgery, and there is no existing method to predict individual surgical outcome. Prior to surgery, patients who become seizure free appear identical to those who continue to have seizures after surgery. Interestingly, newly converging presurgical data from magnetic resonance imaging (MRI) and intracranial electroencephalography (EEG) suggest that the entorhinal and perirhinal cortices may play an important role in seizure generation. These areas are not consistently resected with surgery and it is possible that they continue to generate seizures after surgery in some patients. Therefore, subtypes of MTLE patients can be considered according to the degree of extrahippocampal damage and epileptogenicity of the medial temporal cortex. The identification of these subtypes has the potential to drastically improve surgical results via optimized presurgical planning. In this review, we discuss the current data that suggests neural network damage in MTLE, focusing on the medial temporal cortex. We explore how this evidence may be applied to presurgical planning and suggest approaches for future investigation.
Abstract: Spatial normalization reshapes an individual's brain to match the shape and size of a template image. This is a crucial step required for group-level statistical analyses. The most popular standard templates are derived from MRI scans of young adults. We introduce specialized templates that allow normalization algorithms to be applied to stroke-aged populations. First, we developed a CT template: while this is the dominant modality for many clinical situations, there are no modern CT templates and popular algorithms fail to successfully normalize CT scans. Importantly, our template was based on healthy individuals with ages similar to what is commonly seen in stroke (mean 65 years old). This template allows studies where only CT scans are available. Second, we derived a MRI template that approximately matches the shape of our CT template as well as processing steps that aid the normalization of scans from older individuals (including lesion masking and the ability to generate high quality cortical renderings despite brain injury). The benefit of this strategy is that the resulting templates can be used in studies where mixed modalities are present. We have integrated these templates and processing algorithms into a simple SPM toolbox (http://www.mricro.com/clinical-toolbox/spm8-scripts).
Abstract: Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. Previous research has demonstrated several trends in human tissue that, undoubtedly, contribute to the development and progression of TLE. In this study we examined resected human hippocampus tissue for a variety of changes including gliosis that might contribute to the development and presentation of TLE. The study subjects consisted of six TLE patients and three sudden-death controls. Clinicopathological characteristics were evaluated by H&E staining. Immunohistological staining and Western blotting methods were used to analyze the samples. Neuronal hypertrophy was observed in resected epileptic tissue. Immunohistological staining demonstrated that activation of astrocytes was significantly increased in epileptic tissue as compared to corresponding regions of the control group. The Western blot data also showed increased CX43 and AQP4 in the hippocampus and downregulation of Kir4.1, α-syntrophin, and dystrophin, the key constituents of AQP4 multi-molecular complex. These tissues also demonstrated changes in inflammatory factors (COX-2, TGF-β, NF-κB) suggesting that these molecules may play an important role in TLE pathogenesis. In addition we detected increases in metabotropic glutamate receptor (mGluR) 2/3, mGluR5 and kainic acid receptor subunits KA1 (Grik4) and KA2 (Grik5) in patients' hippocampi. We noted increased expression of the α1c subunit comprising class C L-type Ca(2+) channels and calpain expression in these tissues, suggesting that these subunits might have an integral role in TLE pathogenesis. These changes found in the resected tissue suggest that they may contribute to TLE and that the kainic acid receptor (KAR) and deregulation of GluR2 receptor may play an important role in TLE development and disease course. This study identifies alterations in number of commonly studied molecular targets associated with astrogliosis, cellular hypertrophy, water homeostasis, inflammation, and modulation of excitatory neurotransmission in hippocampal tissues from TLE patients.
Abstract: Removal of the anterior temporal lobe (ATL) is an effective surgical treatment for intractable temporal lobe epilepsy but carries a risk of language and verbal memory deficits. Preoperative localization of functional zones in the ATL might help reduce these risks, yet fMRI protocols in current widespread use produce very little activation in this region. Based on recent evidence suggesting a role for the ATL in semantic integration, we designed an fMRI protocol comparing comprehension of brief narratives (Story task) with a semantically shallow control task involving serial arithmetic (Math task). The Story > Math contrast elicited strong activation throughout the ATL, lateral temporal lobe, and medial temporal lobe bilaterally in an initial cohort of 18 healthy participants. The task protocol was then implemented at 6 other imaging centers using identical methods. Data from a second cohort of participants scanned at these centers closely replicated the results from the initial cohort. The Story-Math protocol provides a reliable method for activation of surgical regions of interest in the ATL. The bilateral activation supports previous claims that conceptual processing involves both temporal lobes. Used in combination with language lateralization measures, reliable ATL activation maps may be useful for predicting cognitive outcome in ATL surgery, though the validity of this approach needs to be established in a prospective surgical series.
Abstract: Lesion-symptom mapping studies are based upon the assumption that behavioral impairments are directly related to structural brain damage. Given what is known about the relationship between perfusion deficits and impairment in acute stroke, attributing specific behavioral impairments to localized brain damage leaves much room for speculation, as impairments could also reflect abnormal neurovascular function in brain regions that appear structurally intact on traditional CT and MRI scans. Compared to acute stroke, the understanding of cerebral perfusion in chronic stroke is far less clear. Utilizing arterial spin labeling (ASL) MRI, we examined perfusion in 17 patients with chronic left hemisphere stroke. The results revealed a decrease in left hemisphere perfusion, primarily in peri-infarct tissue. There was also a strong relationship between increased infarct size and decreased perfusion. These findings have implications for lesion-symptom mapping studies as well as research that relies on functional MRI to study chronic stroke.
Abstract: Past studies reported more widespread structural brain abnormalities in patients with left compared to right temporal lobe epilepsy (TLE), but the profile of these differences remains unknown. This study investigated the relationship between cortical thinning, white matter compromise, epilepsy variables, and the side of seizure onset, in patients with TLE.
Abstract: Studies in patients with extracranial carotid disease have shown that high-resolution magnetic resonance direct thrombus imaging (MRDTI) can reliably identify intraplaque hemorrhage, which may be a better predictor of clinical events than traditional radiographic methods such as percent stenosis. We present the use of high-resolution magnetic resonance imaging for the detection of intraplaque hemorrhage in the intracranial arteries.
Abstract: Understanding the neural mechanism that supports preserved language processing in aphasia has implications for both basic and applied science. This study examined brain activation associated with correct picture naming in 15 patients with aphasia. We contrasted each patient's activation to the activation observed in a neurologically healthy control group, allowing us to identify regions with unusual activity patterns. The results revealed that increased activation in preserved left hemisphere areas is associated with better naming performance in aphasia. This relationship was linear in nature; progressively less cortical activation was associated with greater severity of anomia. These findings are consistent with others who suggests that residual language function following stroke relies on preserved cortical areas in the left hemisphere.
Abstract: Neuroimaging studies suggest that a fronto-parietal network is activated when we expect visual information to appear at a specific spatial location. Here we examined whether a similar network is involved for auditory stimuli. We used sparse fMRI to infer brain activation while participants performed analogous visual and auditory tasks. On some trials, participants were asked to discriminate the elevation of a peripheral target. On other trials, participants made a nonspatial judgment. We contrasted trials where the participants expected a peripheral spatial target to those where they were cued to expect a central target. Crucially, our statistical analyses were based on trials where stimuli were anticipated but not presented, allowing us to directly infer perceptual orienting independent of perceptual processing. This is the first neuroimaging study to use an orthogonal-cuing paradigm (with cues predicting azimuth and responses involving elevation discrimination). This aspect of our paradigm is important, as behavioral cueing effects in audition are classically only observed when participants are asked to make spatial judgments. We observed similar fronto-parietal activation for both vision and audition. In a second experiment that controlled for stimulus properties and task difficulty, participants made spatial and temporal discriminations about musical instruments. We found that the pattern of brain activation for spatial selection of auditory stimuli was remarkably similar to what we found in our first experiment. Collectively, these results suggest that the neural mechanisms supporting spatial attention are largely similar across both visual and auditory modalities.
Abstract: Medial temporal epilepsy (MTLE) is associated with extrahippocampal brain atrophy. The mechanisms underlying brain damage in MTLE are unknown. Seizures may lead to neuronal damage, but another possible explanation is deafferentation from loss of hippocampal connections. This study aimed to investigate the relationship between hippocampal deafferentation and brain atrophy in MTLE.
Abstract: It is unclear whether extrahippocampal brain damage in patients with medial temporal lobe epilepsy (MTLE) is a homogeneous phenomenon, as most data relates to the average volume reduction in groups of patients. This study aimed to evaluate where and how much atrophy is to be expected in an individual patient with MTLE.
Abstract: Patients with left hemisphere damage and concomitant aphasia usually have difficulty repeating others' speech. Although impaired speech repetition, the primary symptom of conduction aphasia, has been associated with involvement of the left arcuate fasciculus, its specific lesion correlate remains elusive. This research examined speech repetition among 45 stroke patients who underwent aphasia testing and MRI examination. Based on lesion-behavior mapping, the primary structural damage most closely associated with impaired speech repetition was found in the posterior portion of the left arcuate fasciculus. However, perfusion-weighted MRI revealed that tissue dysfunction, in the form of either frank damage or hypoperfusion, to the left inferior parietal lobe, rather than the underlying white matter, was associated with impaired speech repetition. This latter result suggests that integrity of the left inferior parietal lobe is important for speech repetition and, as importantly, highlights the importance of examining cerebral perfusion for the purpose of lesion-behavior mapping in acute stroke.
Abstract: It is unclear whether the production and perception of speech movements are subserved by the same brain networks. The purpose of this study was to investigate neural recruitment in cortical areas commonly associated with speech production during the production and visual perception of speech.
Abstract: Hippocampal sclerosis is frequently associated with hippocampal atrophy (HA), which is often observed on routine magnetic resonance imaging (MRI) of patients with medial temporal lobe epilepsy (MTLE). Manual morphometry of the hippocampus is sensitive to detecting HA, but is time-consuming and prone to operator error. Automated MRI morphometry has the potential to provide rapid and accurate assistance in the clinical detection of HA.
Abstract: There are quantifiable abnormalities in water diffusion properties of the white matter in thalamic and prefrontal areas in patients with idiopathic dystonia (ID). However, it is unclear which pathways are disrupted in these patients. Using probabilistic tractography of high resolution DTI, we reconstructed thalamic prefrontal pathways in seven patients with ID and seven matched controls. Resulting fibers were registered onto the stereotaxic space and submitted to a voxel-wise statistical analysis comparing patients and controls. Patients with ID exhibited less thalamic prefrontal connections, particularly involving fibers traveling from the thalamus to the middle frontal gyrus. These results corroborate neurophysiologic findings of reduced and asynchronous thalamic prefrontal input, and emphasize the structural correlates of the pathophysiology of ID.
Abstract: Experimental animal studies have shown that physical exercise, associated with planning and execution of complex movements, are related to changes in brain structure. In humans, changes in cortical tissue density in relation to physical activity are yet to be fully determined and quantified. We investigated differences on gray matter volume in judo players by using voxel-based morphometry. Comparison between a group of eight internationally competitive judo players and a group of 18 healthy controls showed a significantly higher gray matter tissue density in brain areas of judo players.
Abstract: Broca's area is crucial for speech production. Several recent studies have suggested that it has an additional role in visual speech perception. This conclusion remains tenuous, as earlier studies used tasks requiring active processing of visual speech movements, which may have elicited conscious subvocalizations. To study whether Broca's area is modulated during passive viewing of speech movements, we conducted a functional MRI experiment where participants detected rare and brief visual targets that were briefly superimposed on two task irrelevant conditions: passive viewing of silent speech versus nonspeech (gurning) facial movements. Comparison revealed Broca's area to be more active when observing speech. These findings provide further support for Broca's area in speech perception and have clear implications for rehabilitation of aphasia.
Abstract: Aging is usually associated with a progressive difficulty in learning new skills. Similarly, the dexterity in the non-dominant hand is usually decreased with age, while the dominant hand maintains a relative preservation in agility. We investigated if age-related volume loss affects the hand areas asymmetrically by comparing structural measures of the dominant hand area versus the non-dominant area. We performed a region of interest analysis of T1-weighted images focusing on the sensorimotor cortex corresponding to the hand area. We evaluated images from young subjects (younger than 65 years of age, n=38, mean age=24+/-7 years) and senior subjects (65 years or older, n=61, mean age =73+/-6 years). We observed that older adults exhibited greater leftward gray matter asymmetry of sensorimotor cortex, due in large part to more pronounced age-related loss of gray matter in the right hemisphere. These results are consistent with evidence that disuse leads to atrophy and suggest that age-related declines in gray matter, and perhaps function, may be limited by increasing the use of the non-dominant hand.
Abstract: It is unclear which factors lead to progressive neuronal damage in mesial temporal lobe epilepsy (MTLE). The objective of this study was to evaluate whether progressive hippocampal and extrahippocampal atrophy occur in patients with MTLE and whether this atrophy is related to seizures.
Abstract: Two primary areas of damage have been implicated in apraxia of speech (AOS) based on the time post-stroke: (1) the left inferior frontal gyrus (IFG) in acute patients, and (2) the left anterior insula (aIns) in chronic patients. While AOS is widely characterized as a disorder in motor speech planning, little is known about the specific contributions of each of these regions in speech. The purpose of this study was to investigate cortical activation during speech production with a specific focus on the aIns and the IFG in normal adults. While undergoing sparse fMRI, 30 normal adults completed a 30-minute speech-repetition task consisting of three-syllable nonwords that contained either (a) English (native) syllables or (b) non-English (novel) syllables. When the novel syllable productions were compared to the native syllable productions, greater neural activation was observed in the aIns and IFG, particularly during the first 10 min of the task when novelty was the greatest. Although activation in the aIns remained high throughout the task for novel productions, greater activation was clearly demonstrated when the initial 10 min was compared to the final 10 min of the task. These results suggest increased activity within an extensive neural network, including the aIns and IFG, when the motor speech system is taxed, such as during the production of novel speech. We speculate that the amount of left aIns recruitment during speech production may be related to the internal construction of the motor speech unit such that the degree of novelty/automaticity would result in more or less demands respectively. The role of the IFG as a storehouse and integrative processor for previously acquired routines is also discussed.
Abstract: Cognitive deficits are of particular importance in schizophrenia since they are strongly associated with poor prognosis. We investigated the relationship between prefrontal cortical atrophy as measured by MRI and the neuropsychological performance of participants diagnosed with DSM-IV-TR schizophrenia.
Abstract: The mechanisms guiding the progression of neuronal damage in patients with Huntington disease (HD) are not completely understood. It is unclear whether the genotype--that is, the length of the expanded CAG repeat--guides the location and speed of grey matter decline once HD is clinically manifested. Moreover, the relationship between cortical and subcortical grey matter atrophy and the severity of motor symptoms of HD is controversial.
Abstract: Recent evidence supports increased cortical activity and impaired brain connectivity in autism, but the structural correlates of these abnormalities are not yet defined. We performed a voxel based morphometry analysis of brain MRI from patients with autism selected from a group of 103 subjects with pervasive developmental disorders. Twelve male patients with mean age of 12.4 +/- 4 years were compared with 16 matched controls. Patients with autism exhibited increase in gray matter in medial and dorsolateral frontal areas, in the lateral and medial parts of the temporal lobes, in the parietal lobes, cerebellum and claustrum. Patients also showed decrease in frontal, parietal, temporal and occipital white matter. The combination of enlarged cortex and reduced white matter is possibly the structural basis of some symptoms of classic autism.
Abstract: Traditionally, the left frontal and parietal lobes have been associated with language production while regions in the temporal lobe are seen as crucial for language comprehension. However, recent evidence suggests that the classical language areas constitute an integrated network where each area plays a crucial role both in speech production and perception. We used functional MRI to examine whether observing speech motor movements (without auditory speech) relative to non-speech motor movements preferentially activates the cortical speech areas. Furthermore, we tested whether the activation in these regions was modulated by task difficulty. This dissociates between areas that are actively involved with speech perception from regions that show an obligatory activation in response to speech movements (e.g. areas that automatically activate in preparation for a motoric response). Specifically, we hypothesized that regions involved with decoding oral speech would show increasing activation with increasing difficulty. We found that speech movements preferentially activate the frontal and temporal language areas. In contrast, non-speech movements preferentially activate the parietal region. Degraded speech stimuli increased both frontal and parietal lobe activity but did not differentially excite the temporal region. These findings suggest that the frontal language area plays a role in visual speech perception and highlight the differential roles of the classical speech and language areas in processing others' motor speech movements.
Abstract: Memory impairment observed in patients with medial temporal lobe epilepsy (MTLE) is classically attributed to hippocampal atrophy. The contribution of extrahippocampal structures in shaping memory impairment in patients with MTLE is not yet completely understood, even though atrophy in MTLE extends beyond the hippocampus. We aimed to evaluate the neuropsychological profile of patients with MTLE focusing on memory, and to investigate whether gray matter concentration (GMC) distribution within and outside the medial portion of the temporal lobes would be associated with their neuropsychological performance. We performed a voxel based morphometry study of 36 consecutive patients with MTLE and unilateral hippocampal atrophy. We observed a significant simple regression between general and verbal memory performance based on Wechsler Memory Scale-Revised and the GMC of medial temporal and extratemporal structures in patients with left MTLE. We also performed a "regions of interest analysis" of the medial temporal lobe, and we observed that the GMC of the hippocampus, entorhinal, and perirhinal cortices were consistently associated with general and verbal memory performance in patients with MTLE. We also observed that the GMC of the cingulate and orbito-frontal cortex are independently associated with verbal and general memory performances. Our results suggest that general and verbal memory impairments in patients with left MTLE are associated with atrophy of the hippocampus, the entorhinal, and the perirhinal cortex. We also suggest that atrophy and dysfunction of limbic and frontal structures such as the cingulate and the orbito-frontal cortex contribute to memory impairment in MTLE.
Abstract: Most naming treatments in aphasia either assume a phonological or semantic emphasis or a combination thereof. However, it is unclear whether semantic or phonological treatments recruit the same or different cortical areas in chronic aphasia. Employing three persons with aphasia, two of whom were non-fluent, the present study compared changes in neural recruitment associated with phonologic and semantic-based naming treatments. The participants with non-fluent aphasia were able to name more items following both treatment approaches. Although this was not the case for the participant who had fluent aphasia, her naming errors decreased considerably following treatment. Post-treatment fMRI revealed similar changes in neural activity bilaterally in the precuneus among the two non-fluent participants--increased activity was noted in the right entorhinal cortex and posterior thalamus on post-treatment scans for the third participant. These findings imply that cortical areas not traditionally related to language processing may support anomia recovery in some patients with chronic aphasia.
Abstract: Surgical removal of the hippocampus is the standard of care of patients with drug-resistant medial temporal lobe epilepsy (MTLE). The procedure carries a success rate of approximately 75%, but the reasons that some patients fail to achieve seizure control after surgery remain inexplicable. The question of whether the resection of medial temporal lobe structures in addition to the hippocampus would influence the surgical outcome in patients with MTLE was examined.
Abstract: Nodular heterotopia (NH) with overlying polymicrogyria can result in medically uncontrolled seizures. Most patients also exhibit deficits of function related to the location of the abnormal cortex. However, functional imaging studies show that the abnormal cortex can retain some function, making surgical planning difficult. It is not known if the connectivity of the abnormal cortex is normal. In this article, we performed an evaluation of molecular diffusion within the white matter in a patient with refractory epilepsy due to NH with overlying polymicrogyria. We observed that the white matter underlying the polymicrogyric area shows signs of microstructural abnormalities. This result suggests that the deficit of function from polymicrogyria result from both the structurally abnormal cortex and from its impaired connectivity.
Abstract: Traditional analysis of neuroimaging data uses parametric statistics, such as the t-test. These tests are designed to detect mean differences. In fact, even nonparametric techniques such as Statistical non-Parametric Mapping (SnPM) use the mean-based t statistic to measure effect size. We note that these measures may not be particularly sensitive for detecting differences when the mean is not an accurate measure of central tendency--for example if one of the groups is experiencing a ceiling or floor effect (causing a skewed data distribution). Here we introduce a nonparametric approach for neuroimaging data analysis that is based on the rank-order of data (and is therefore less influenced by outliers than the t-test). We suggest that this approach may offer a small benefit for datasets where the assumptions of the t-test have been violated, for example datasets where data from one of the groups exhibits a skewed distribution due to floor or ceiling effects.
Abstract: Structural neuroimaging studies have consistently shown a pattern of extra-hippocampal atrophy in patients with left and right drug-refractory medial temporal lobe epilepsy (MTLE). However, it is not yet completely understood how extra-hippocampal atrophy is related to hippocampal atrophy. Moreover, patients with left MTLE often exhibit more intense cognitive impairment, and subtle brain asymmetries have been reported in patients with left MTLE versus right MTLE but have not been explored in a controlled study.
Abstract: We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1-negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia.
Abstract: Cerebral atrophy has been described to occur in systemic lupus erythematosus (SLE) with variable frequency. The aim of this study was to determine white and gray matter abnormalities in brain magnetic resonance imaging (MRI) of patients with SLE and to determine if these abnormalities progress over a one-year period. Seventy-five patients with SLE and 44 healthy age and sex-matched controls were enrolled in this study. T1-weighted volumetric images were used for voxel based morphometry (VBM) analyses. SLE patients exhibited a significant reduction in white matter and gray matter volume compared to controls (p=0.001). Follow-up images, after an average interval of 19 months, revealed a progressive white matter and gray matter atrophy (p=0.001). Reduced white and gray matter volume was associated with disease duration and the presence of antiphospholipid antibodies. Patients with severe cognitive impairment had a more pronounced white and gray matter reduction than patients with moderate cognitive impairment. Total corticosteroid dose was associated with gray matter reduction and not with white matter loss in SLE patients. We concluded that brain tissue loss associated with SLE is significant and progresses over a relatively short period of time. Disease duration, the presence of antiphospholipid antibodies and cognitive impairment were associated with white and gray matter loss. Corticosteroid was associated only with gray matter atrophy.
Abstract: Motor training results in performance improvement. It is not yet fully understood the extent to which functional improvement is reflected in changes in brain structure. To investigate the presence and degree of structural brain plasticity induced by long-term bimanual motor activity, we studied 17 right-handed professional typists with average duration of typing practice of 11 years. Using optimized voxel-based morphometry, we correlated the duration of practice and grey matter volume. Regions of interest were applied using 116 previously segmented predefined brain sites. We found a significant positive regression between grey matter volume and duration of practice in brain regions related to the programming of motor tasks. Long-term bimanual training may increase grey matter volume in the brains of professional typists.
Abstract: To identify the prevalence of zinc deficiency in a population with high prevalence of vitamin A deficiency; to verify whether zinc deficiency is associated with vitamin A deficiency in the population studied; to verify risk factors for zinc deficiency (sex, age, diarrhea and fever).
Abstract: The goals of the work described here were to determine if hippocampal and extrahippocampal atrophy in children with temporal lobe epilepsy (TLE) follows a pattern similar to that in adult patients, and to assess the clinical and neuropsychological relevance of regional brain atrophy in pediatric TLE.
Abstract: Measures of brain activation (e.g., changes in scalp electrical potentials) have become the most popular method for inferring brain function. However, examining brain disruption (e.g., examining behavior after brain injury) can complement activation studies. Activation techniques identify regions involved with a task, whereas disruption techniques are able to discover which regions are crucial for a task. Voxel-based lesion mapping can be used to determine relationships between behavioral measures and the location of brain injury, revealing the function of brain regions. Lesion mapping can also correlate the effectiveness of neurosurgery with the location of brain resection, identifying optimal surgical targets. Traditionally, voxel-based lesion mapping has employed the chi-square test when the clinical measure is binomial and the Student's t test when measures are continuous. Here we suggest that the Liebermeister approach for binomial data is more sensitive than the chi-square test. We also suggest that a test described by Brunner and Munzel is more appropriate than the t test for nonbinomial data because clinical and neuropsychological data often violate the assumptions of the t test. We test our hypotheses comparing statistical tests using both simulated data and data obtained from a sample of stroke patients with disturbed spatial perception. We also developed software to implement these tests (MRIcron), made freely available to the scientific community.
Abstract: Pronouns are commonly used instead of explicitly repeating a name, and, in many cases, we comprehend language faster when pronouns are used instead of repetitive references. This is surprising because pronouns are often ambiguous, whereas repeated names provide precise reference. We used functional MRI to investigate the neural correlates of this paradoxical preference. Reading repeated names elicited more activation than pronouns in the middle and inferior temporal gyri and intraparietal sulcus. The temporal lobe activation suggests that repeated names but not pronouns evoke multiple representations that have to be integrated. The intraparietal sulcus activation suggests that this integration relies on brain regions used for spatial attention and perceptual integration.
Abstract: In spite of the growing number of seniors who drive and their relatively frequent involvement in accidents, little is known about the cognitive substrates of road hazard recognition and their relationship with general cognitive performance in this population. We aimed to investigate, using a combination of functional MRI (fMRI) and a comprehensive neuropsychological battery, the anatomical and cognitive components of driving hazard recognition.
Abstract: Chronic medial temporal lobe epilepsy (MTLE) is associated with memory loss due to damage in the hippocampal system. To investigate the relationship between volume of medial temporal lobe structures and performance on neuropsychological tests, we studied 39 consecutive patients with MTLE and unilateral hippocampal atrophy (HA) determined by volumetric magnetic resonance imaging (MRI). Structures of interest comprised hippocampus, amygdala, and entorhinal, perirhinal, parahippocampal, and temporopolar cortices. The findings indicated that (1) performance was significantly worse in the group with left HA as compared with the group with right HA on general memory, verbal memory, delayed recall, and verbal fluency tests and the Boston Naming Test (BNT), and (2) the volume of the left hippocampus and also the degree of asymmetry of perirhinal cortex volume were significant and independent predictors of performance on general memory, verbal memory, and verbal fluency tests and the BNT in patients with MTLE.
Abstract: The posterior parietal cortex (PPC) is thought to integrate different kinds of sensory information (e.g., visual, auditory, somatosensory) to produce multiple representations of space that are each associated with different types or combinations of action; such as saccadic eye movements and reaching or grasping movements of the upper limb. Lesion studies in monkeys and in humans have shown that reaching movements to visually defined and to posturally defined targets can be dissociated from one another; indicating that different regions of the parietal cortex may code the same movement in either extrinsic (visual) or intrinsic (postural) coordinates. These studies also suggest that regions within the posterior parietal cortex play an important role in maintaining an accurate and up-to-date representation of the current postural state of the body (the body schema). We used event-related functional magnetic resonance imaging (fMRI) to investigate those brain areas involved in maintaining and updating postural (i.e., non-visual) representations of the upper limb that participate in the accurate control of reaching movements. We show that a change in the posture of the upper-limb is associated with a significant increase in BOLD activation in only one brain region--the superior parietal cortex, particularly the medial aspect (precuneus). We note that this finding is consistent with the suggestion, based upon human neurological investigations and monkey electrophysiology, that this region of the PPC may participate in the dynamic representation of the body schema, and is the most likely location for damage leading to errors in visually guided reaching to non-foveated target locations. We also note that this brain area corresponds to a region of PPC recently identified as the human homologue of the Parietal Reach Region (PRR) observed in the monkey brain that has been thought to represent reaching movements in eye-centred coordinates.
Abstract: Many patients with focal cortical dysplasia (FCD) continue to have seizures after surgical treatment. The usual explanation for the poor surgical outcome is the presence of residual dysplastic tissue missed by the preoperative neuroimaging investigation and therefore not resected during surgery. We apply a voxel-based morphometry (VBM) analysis to the magnetic resonance imaging (MRI) scans from patients with epilepsy and visually detected FCD to investigate whether (a) VBM is able to detect gray-matter concentration (GMC) abnormalities in patients with FCD, and (b) whether the extent of GMC abnormalities in the brain of these patients differs from the regions observed by using visual inspection.
Abstract: Transcranial magnetic stimulation (TMS) is a popular technique that can be used to investigate the functional role of specific cortical areas with reference to a particular behavioural task. Single-cell recording studies performed in non-human primates have demonstrated that a region of the parietal lobe known as the lateral intraparietal area is specialized in the planning and control of saccadic eye movements. The homologue of this area in humans is termed the parietal eye fields (PEF) and its role in relation to saccades has previously been examined using TMS. In this paper individual variability in the functional effect of parietal TMS on the latency, amplitude and angular direction of visually-guided saccades has been assessed. By examining individual variability in the spatial distribution of scalp-based localization and brain surface anatomy and stereotaxic localizations of the PEF it was shown that the distances between the sites determined by these three methods were not negligible, which raises problems regarding the most reliable anatomical localization technique to use. An assessment of the effect of TMS on saccade metrics (latency, amplitude error and angular error) at a grid of locations over parietal cortex demonstrated a large amount of intra-individual variability in the site where TMS had most affected saccades, leading to the conclusion that there is individual variability in the functional effects of parietal TMS on saccade planning and execution. This study confirms the idea that it may be problematic to use a fixed scalp location for every participant in a study. It may in fact be more appropriate to determine TMS sites functionally on an individual basis if possible. This finding may guide further studies using TMS and saccade planning in order to optimize their capability to investigate this area and to draw meaningful biological conclusions.
Abstract: Apraxia of speech, usually associated with stroke, refers to the inability to perform speech motor movements typically with an intact ability to execute non-speech oral movements. It is uncertain whether apraxia of speech results from damage affecting the insula or the inferior frontal gyrus. The controversy started because of conflicting results from studies investigating patients with disrupted brain structure, when dysfunction of both sites can coexist. We conducted a functional magnetic resonance imaging study of individuals without neurological disorders comparing speech and non-speech movements. Speech movements did not recruit the insula, but activated the left inferior frontal gyrus, suggesting that Broca's area, but not the insula, is critical for speech articulation.
Abstract: Quantification of increased T2-weighted MRI signal that is associated with hippocampal sclerosis (HS) can be performed through (1) mean of hippocampal signal in single-echo T2 MRI and (2) hippocampal T2 relaxometry. It is not clear whether these two techniques are equivalent. In this study, we compare the hippocampal signal, detected by single-echo T2 quantification and by T2 relaxometry, in patients with medial temporal lobe epilepsy (MTLE).
Abstract: Hippocampal sclerosis is the most common abnormality associated with medial temporal lobe epilepsy (MTLE). Converging evidence supports that hippocampal sclerosis progresses with time. However, it is unclear whether extrahippocampal atrophy in patients with MTLE, similarly to hippocampal sclerosis, is an unremitting progressive process. In this article, we investigate the relationship between duration of epilepsy and gray matter concentration reduction in patients with MTLE within and outside the hippocampus. We employed a voxel-based morphometry study of MRI of the entire brain of 36 patients with drug refractory MTLE and 49 neurologically healthy age-matched controls. We performed a voxel-based parametric and nonparametric investigation of the association between gray matter concentration, age and duration of epilepsy. We complemented the investigation by extracting the gray matter concentration of regions of interest (ROIs) within the limbic system, and we investigated the association between the gray matter concentration on the ROIs and duration of epilepsy. Patients with MTLE exhibited gray matter concentration reduction that is negatively correlated with the duration of epilepsy within the ipsilateral hippocampus, temporal lobes as well as extratemporal limbic structures that are closely connected with the hippocampus. In conclusion, longer duration of refractory epilepsy was associated with a more intense hippocampal and extrahippocampal atrophy in patients with MTLE. The mechanism of progressive neuronal damage in MTLE may be related to active seizure activity within a limbic network, and early seizure control may prevent further brain atrophy in patients with refractory MTLE.
Abstract: To illustrate the profile of the cases of intoxications by antiepileptic drugs (AEDs) registered within a large urban area during the period of 1 year.
Abstract: There is a wide range of values reported in volumetric studies of the amygdala. The use of single plane thick magnetic resonance imaging (MRI) may prevent the correct visualization of anatomic landmarks and yield imprecise results. To assess whether there is a difference between volumetric analysis of the amygdala performed with single plane MRI 3-mm slices and with multiplanar analysis of MRI 1-mm slices, we studied healthy subjects and patients with temporal lobe epilepsy. We performed manual delineation of the amygdala on T1-weighted inversion recovery, 3-mm coronal slices and manual delineation of the amygdala on three-dimensional volumetric T1-weighted images with 1-mm slice thickness. The data were compared using a dependent t-test. There was a significant difference between the volumes obtained by the coronal plane-based measurements and the volumes obtained by three-dimensional analysis (P < 0.001). An incorrect estimate of the amygdala volume may preclude a correct analysis of the biological effects of alterations in amygdala volume. Three-dimensional analysis is preferred because it is based on more extensive anatomical assessment and the results are similar to those obtained in post-mortem studies.
Abstract: Previous research has suggested that patients with refractory medial temporal lobe epilepsy (MTLE) show gray matter atrophy both within the temporal lobes as well as in the thalamus. However, these studies have not distinguished between different nuclei within the thalamus. We examined whether thalamic atrophy correlates with the nuclei's connections to other regions in the limbic system. T1-weighted MRI scans were obtained from 49 neurologically healthy control subjects and 43 patients diagnosed with chronic refractory MTLE that was unilateral in origin (as measured by ictal EEG and hippocampal atrophy observed on MRI). Measurements of gray matter concentration (GMC) were made using automated segmentation algorithms. GMC was analyzed both voxel-by-voxel (preserving spatial precision) as well as using predefined regions of interest. Voxel-based morphometry revealed intense GMC reduction in the anterior portion relative to posterior thalami. Furthermore, thalamic atrophy was greater ipsilateral to the MTLE origin than on the contralateral side. Here we demonstrate that the thalamic atrophy is most intense in the thalamic nuclei that have strong connections with the limbic hippocampus. This finding suggests that thalamic atrophy reflects this region's anatomical and functional association with the limbic system rather than a general vulnerability to damage.
Abstract: To identify the prevalence of iron deficiency in the population studied, as well as verifying if such deprivation is associated with vitamin A deficiency.
Abstract: To investigate the pattern of perfusion abnormalities in ictal and interictal brain perfusion SPECT images (BSI) from patients with temporal lobe epilepsy (TLE).
Abstract: INTRODUCTION: Central neurocytomas are rare neuroectodermal tumors believed to arise from the subependymal matrix of the lateral ventricles. CASE REPORTS: A 26-year-old woman and a 33-year-old man each had a large, heterogeneous, contrast enhancing mass in the lateral ventricles at the foramen of Monro causing bilateral hydrocephalus. The woman died after surgery, but the man is asymptomatic after three years. HISTOPATHOLOGY: Both tumors were composed of isomorphic rounded cells positive for synaptophysin, chromogranin and NSE, while some reacted for GFAP, vimentin and S-100 protein. Electron microscopy revealed neuropil-like tissue between cells, but synapses were rare.
Abstract: Spinal schwannomas are frequently observed among patients treated in a reference neurosurgery center. Cystic spinal schwannomas, however, are very scantly found. Due to its indolent behavior and benign course, the diagnosis of schwannomas may pose a challenge to the care giver, and the imaging findings can be misleading. In this article, we illustrate an example of a pauci-symptomatic 55 year-old male patient whose complaint was solely a non specific lumbar pain. Investigation revealed a large cystic lesion comprising the lower lumbar intradural space. He was then treated with microneurosurgical technique involving complete removal of the tumor and reconstruction of the dura mater. Histological and immunohistochemical diagnosis were consistent with cystic schwannoma. The patient presented with complete recovery of his symptom. In this article we aim to emphasize the clinical presentation and treatment of lumbar spine schwannomas, and to illustrate the imaging findings within this uncommon case.
Abstract: Quantitative analysis of brain structures in normal subjects and in different neurological conditions can be carried out in vivo through magnetic resonance imaging (MRI) volumetric studies. The use of high-resolution MRI combined with image post-processing that allows simultaneous multiplanar view may facilitate volumetric segmentation of temporal lobe structures. We define a protocol for volumetric studies of medial temporal lobe structures using high-resolution MR images and we studied 30 healthy subjects (19 women; mean age, 33 years; age range, 21-55 years). Images underwent field non-homogeneity correction and linear stereotaxic transformation into a standard space. Structures of interest comprised temporopolar, entorhinal, perirhinal, parahippocampal cortices, hippocampus, and the amygdala. Segmentation was carried out with multiplanar assessment. There was no statistically significant left/right-sided asymmetry concerning any structure analyzed. Neither gender nor age influenced the volumes obtained. The coefficient of repeatability showed no significant difference of intra- and interobserver measurements. Imaging post-processing and simultaneous multiplanar view of high-resolution MRI facilitates volumetric assessment of the medial portion of the temporal lobe with strict adherence to anatomic landmarks. This protocol shows no significant inter- and intraobserver variations and thus is reliable for longitudinal studies.
Abstract: Vitamin A deficiency (VAD) is endemic in Brazil and health professionals have difficulty in recognizing its subclinical form. In addition, serum retinol concentrations do not always represent vitamin A status in the organism.
Abstract: Dietary habits have been rarely associated with seizure frequency in patients with epilepsy. We report a case of a man with a partial symptomatic epilepsy whose daily habit of heavy coffee drinking was associated with an increased seizure frequency. This patient witnessed a dramatic decrease in the frequency of his seizures after stopping coffee ingestion. Caffeine is a global stimulant and the reduction of its intake may help in the treatment of epilepsy.
Abstract: Seizures are a symptom of an underlying brain disorder. The accurate identification of the nature of the disease generating the seizures facilitates treatment and can prevent further brain damage. The understanding of the physiopathology underlying the seizures has been greatly enhanced by the possibility to examine these patients with advanced forms of neuroimaging. Among different forms of investigation, neuroimaging techniques play a major role in diagnosis and decision-making in the care of patients with epilepsy. We review the contributions of current methods of imaging in the investigation of patients with single seizures, febrile seizures or refractory seizures, assessing the practical aspects, benefits, and operational costs of various neuroimaging techniques. The focus is on MRI, which is the imaging modality of choice for outpatient investigation. We also assessed the benefits from CT scans, which remain the first option for emergency seizure assessment. The aim was to evaluate how the structural, functional and metabolic information provided by modern techniques of neuroimaging decreases the need for additional investigation and speeds the management of these epileptic disorders. This makes it possible to accurately define the location and the nature of the epileptogenic lesions related to seizures.
Abstract: We report a case of a young female patient with a rare and recently described form of brain tumor. This patient had a history of headache, hemiparesis and motor simple partial seizures. Her investigation revealed a brain tumor involving the left frontal and parietal lobes. The radiological images showed a cystic mass with multiple nodular masses and a rim of contrast enhancement extending from the right parietal cortex to the ipsilateral ventricle and corpus callosum. The patient underwent gross resection of the lesion and the histological analysis of the surgical specimen revealed a pseudopapillary structure formed by delicate vessels intermixed with a fibrillary pattern and bordered by intense astrocytic reaction with Rosenthal fibers. These features correspond to the recently described mixed neuronal-glial neoplasm, the papillary glioneuronal tumor. The patient has been followed for five years since the surgical treatment, without evidence of tumor recurrence, confirming the indolent behavior of this type of tumor.
Abstract: The analysis of texture parameters is a useful way of increasing the information obtainable from medical images. It is an ongoing field of research, with applications ranging from the segmentation of specific anatomical structures and the detection of lesions, to differentiation between pathological and healthy tissue in different organs. Texture analysis uses radiological images obtained in routine diagnostic practice, but involves an ensemble of mathematical computations performed with the data contained within the images. In this article we clarify the principles of texture analysis and give examples of its applications, reviewing studies of the technique.
Abstract: Unilateral hippocampal atrophy is indicator of good surgical prognosis in patients with temporal lobe epilepsy (TLE). Some patients however do not become seizure free after surgery. We assessed if the extent of hippocampal and amygdala resection is associated with outcome.
Abstract: Symptomatic acute epileptic seizures may occur in up to 5% of individuals, especially children, with scorpion stings. The occurrence of a long-lasting brain lesion or the development of epilepsy after a scorpion sting has never been observed.
Abstract: Conventional volumetric studies have shown that brain structures functionally and anatomically related to the hippocampus are smaller in patients with drug-refractory medial temporal lobe epilepsy (MTLE).
Abstract: We assessed the effect of the method of analysis and the MRI slice thickness on entorhinal cortex volumetry. A T1 gradient echo 3D volumetric acquisition was reformatted into different slice thickness and analyzed by edge-tracing. We performed two different forms of analysis of images with 3 mm slice thickness: edge-tracing and pixel by pixel. There was difference among the volumes obtained from different slice thickness (p < 0.001), and also difference between the two different methods of analysis (p < 0.05). The use of thick slices is time saving, but volumes are linearly increased; different methods of segmentation also yields different values. The form of volumetric analysis of the entorhinal cortex should be evaluated in advance to prevent false estimates in longitudinal studies.
Abstract: We present the case of a 30-year female patient with multiple systemic metastases of posterior fossa primitive neuroectodermal tumor (PF- PNET) and present a review concerning the usual presentation, sign and symptoms, radiological aspects, pathways of spread, genetic patterns and treatment of PF-PNET. The biological behavior of PF - PNET is analyzed taking into consideration the presence of systemic metastases.
Abstract: Mesial temporal lobe epilepsy (MTLE) is frequently associated with refractory seizures and pathologic features of hippocampal sclerosis (HS). Quantitative magnetic resonance imaging (MRI) techniques can improve the detection and quantification of HS. The objective of this study was to evaluate whether MRI texture analysis can detect hippocampal abnormalities in patients with pathologically proven HS.
Abstract: The objective of this study was to assess the volumes of medial temporal lobe structures using high resolution magnetic resonance images from patients with chronic refractory medial temporal lobe epilepsy (MTLE).
Abstract: Epidural hematomas of the cranial vertex can be rarely found in patients victims of head trauma. The diagnosis of the vertex hematoma may be delayed by the odd location of the bleeding site and the absence of a clear localization symptomatology. The current method of choice for investigation of head trauma patients, the computed tomography (CT) scans, may also give misleading diagnostic clues. Epidural hematomas of the vertex can be also encountered in a chronic form, and re-bleeding is possibly the underlying mechanism for the long term permanence of the hematoma. We report a case of a patient with a chronic epidural hematoma of the cranial vertex with a long interval between the trauma and the symptoms onset. We review the current literature focusing on the diagnostic pitfalls and forms of treatment of the chronic epidural hematoma of the vertex.
Abstract: Internuclear ophthalmoplegia is a remarkable finding, particularly in patients victims of head injury. The medial longitudinal fasciculus, which is believed to be lesioned in cases of internuclear ophthalmoplegia, has an unique brain stem position and the mechanism involved in brain stem contusions implies a maximal intensity of shearing forces on the skull base. We describe a very rare association of bilateral ophthalmoplegia and clivus fracture following head injury, without further neurological signs. The patient history, his physical examination and the image investigation provide additional evidence to some of the mechanisms of injury proposed to explain post-traumatic internuclear ophthalmoplegia.
Abstract: Clinical and surgical outcome of patients with subarachnoid hemorrhage (SAH) due to ruptured aneurysm were assessed in comparison to pre-operative data and risk factors such as previous medical history, clinical presenting condition, CT findings and site of bleeding.
Abstract: Trauma to the soft palate is a uncommon event during childhood. Stroke following intraoral trauma is also rare, but has been well documented by the current literature as a potentially serious complication. In this article, we report 2 cases of posttraumatic internal carotid artery thrombosis depicted by imaging studies. We discuss pathogenesis, and the literature is reviewed.
Abstract: The incidence of dog bites injuries among children aged 0 to 15 years seen at CSE D. Pedro I health center in Ribeirão Preto, Brazil, in the period of 1993 to 1997, was studied. The results show that there is a need to develop and implement educational and preventive programs about the risks and severity of accidents occurred while in contact with dogs.
Abstract: A 74 year-old patient with a nocturnal onset of neck and chest pain was brought to an emergency clinic. Physical examination and cardiac assessment were normal. Three hours after the addmittance, a flaccid paralysis of the four limbs supervened. Suspecting of an unusual onset of central nervous system infection, a lumbar puncture was performed, yielding 20 ml of normal cerebrospinal fluid. Thirty oinutes after the puncture, the patient completely regained neurological funcion. He was then referred to a General Hospital where a computed tomography (CT) scan was done showing a large cervical epidural bleeding in the posterolateral region of C4/C5 extending to C7/Th1, along with a C6 vertebral body hemangioma. A magnetic resonance imaging revealed the same CT findings. A normal selective angiography of vertebral arteries, carotid arteries and thyreocervical trunk was carried out. Spontaneous spinal epidural hematoma (ASSEH) is a rare but dramatic cause of neurological impairment. In this article we report a fortunate case of complete recovery after an unusual spine cord decompression. We also review the current literature concerning diagnosis and treatment of ASSEH.
Abstract: Administration of fractionated doses of irradiation is part of the adjutant therapy for CNS tumours such as craniopharyngiomas and pituitary adenomas. It can maximise cure rates or expand symptom-free period. Among the adverse effects of radiotherapy, the induction of a new tumour within the irradiated field has been frequently described. The precise clinical features that correlate irradiation and oncogenesis are not completely defined, but some authors have suggested that tumors are radiation induced when they are histologically different from the treated ones, arise in greater frequency in irradiated patients than among normal population and tend to occur in younger people with an unusual aggressiveness. In this article, we report a case of a papillary astrocytoma arising in a rather unusual latency period following radiotherapy for craniopharyngioma.
Abstract: Pilonidal cysts and sinuses are described as dermoid cysts which contain follicles of hairs and sebaceous glands. They clinically present as a classic case of inflammation which comes with pain, local infection and redness. The origin of pilonidal disease remains controverse. There are many hypothesis as lack of hygiene on the affected area and a penetration and growth of a hair in the subcutaneous tissue caused by constant friction or direct trauma on the damaged area. The option for clinical treatment is very frequent. However, taking into consideration the incidence and the possibility of recidive, surgical treatment is presently recommended. Complications include cellulitis and abscess formation. Pilonidal cysts are mostly found on the sacral region. In the literature is found description of pilonidal cysts on the penis, interdigital region on the hands as well as on the cervical region. We present a case of pilonidal cyst located on the vault biparietal region, without malignant degeneration.
Abstract: We report four cases of surgically treated intracranial arachnoid cysts, one with cyst-peritoneal shunt and three with craniotomy and arachnoid membrane resection. Their classification and etiopathogeny are discussed, and especially the different methods of treatment comparing the drastic complications (adversities) with the favorable solutions in severe clinical cases (plasticity) treated at our institution.
