Focal Brain Lesions Research Articles

Focal brain lesions induce spontaneous and evoked sleep-like intracerebral activity in awake humans

Focal brain lesions induce spontaneous and evoked sleep-like intracerebral activity in awake humans

Limits on using the clock drawing test as a measure to evaluate patients with neurological disorders

BackgroundThe Clock Drawing Test (CDT) is used as a quick-to-conduct test for the diagnosis of dementia and a screening tool for cognitive impairments in neurological disorders. However, the association between the pattern of CDT impairments and the location of brain lesions has been controversial. We examined whether there is an association between the CDT scores and the location of brain lesions using the two available scoring systems.MethodOne hundred five patients with brain lesions identified by CT scanning were recruited for this study. The Montreal Cognitive Assessment (MoCA) battery including the CDT were administered to all partcipants. To score the CDT, we used a qualitative scoring system devised by Rouleau et al. (1992). For the quantitative scoring system, we adapted the algorithm method used by Mendes-Santos et al. (2015) based on an earlier study by Sunderland et al. (1989). For analyses, a machine learning algorithm was used.ResultsRemarkably, 30% of the patients were not detected by the CDT. Quantitative and qualitative errors were categorized into different clusters. The classification algorithm did not differentiate the patients with traumatic brain injury ‘TBI’ from non-TBI, or the laterality of the lesion. In addition, the classification accuracy for identifying patients with specific lobe lesions was low, except for the parietal lobe with an accuracy of 63%.ConclusionThe CDT is not an accurate tool for detecting focal brain lesions. While the CDT still is beneficial for use with patients suspected of having a neurodegenerative disorder, it should be cautiously used with patients with focal neurological disorders.

497: ROLE OF AUTOMATED PUPILLOMETRY IN NEUROLOGIC ASSESSMENT OF POST-ANGIOGRAPHY PATIENTS

Introduction: Automated pupillometry (AP) is an objective bedside tool that can be used to detect early global or regional cerebral dysfunction manifested as asymmetric pupillary light response (PLR). Early detection of neurologic changes after diagnostic or interventional neuroradiologic procedure is important to limit neurologic morbidity and initiate appropriate intervention. In this pilot project, we hypothesized that changes in PLR between pre and post angiography will correlate with pathological changes in the brain. Methods: Single-center, prospective cohort of 50 patients undergoing elective or emergent angiography. 200 PLR recordings were assessed using NPi™-300 Pupillometer. Different PLR properties was recorded 30-min pre and post angiography. Fisher exact test and Kruskal-Wallis test was used to evaluate the relationship between continuous variable and univariate analysis to evaluate associations between categorical variables or mean values of specific parameters. A paired t-test was used to evaluate the differences between pre and post angiography PLR. A p-value < 0.05 was considered statistically significant. Results: Comparing pre and post angiography values, no variables showed a statistically significant difference (p< 0.05) except for the constricted pupil diameter in the left eye (LE) (paired t-test, p=0.03). Comparison of PLR in patients with focal mass lesion showed significant difference in constriction velocity, resting pupil diameter, dilation velocity in the LE, and constricted diameter of both LE and right eye (paired t-test, P 0.005, P = 0.002, P = 0.0098 and P = 0.0023 respectively). For patients who established reperfusion, there were no statistically significant differences in PLR. Conclusions: Our study provides preliminary data regarding the role of AP in documenting PLR abnormalities at baseline in patients with focal brain lesion who underwent angiography. Pre and post intervention PLR changes were not found in our study probably due to absence of major post-intervention complications but would need larger study to verify such hypothesis. This suggests that any changes to PLR is not an expected procedural change and should be treated appropriately.

Diagnostic value of EBV-DNA in CSF for PCNSL in AIDS patients with focal brain lesions: A meta-analysis of diagnostic test

Epstein-Barr virus (EBV) infection plays a crucial role in the progression of acquired immunodeficiency syndrome related primary central nervous system lymphoma (AR-PCNSL). This study aimed at evaluating the diagnostic value of cerebrospinal spinal fluid (CSF) EBV-deoxyribonucleic acid (DNA) for PCNSL in patients with infection of human immunodeficiency (HIV) virus through a meta-analysis of diagnostic test. A systematic search in PubMed, Embase, Web of Science, Wanfang, Chinese Biomedical Database and Chinese National Knowledge Infrastructure was conducted before May 10, 2022. Heterogeneity among the studies was assessed using Q test and I2 statistics. Publication bias was assessed using the Deek's funnel plot asymmetry test. Statistical analyses were performed using Stata 16.0 software. The pooled sensitivity, specificity, positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratios (DOR) and 95% confidence intervals (CI) were caculated to evaluate the diagnostic value. A symmetric receiver operating characteristic (SROC) curve and the area under the SROC curve (AUC) were constructed to evaluate the test-performance. Twelve studies were included in the final analyses, with a total of 141 patients with AR-PCNSL and 590 controls. The pooled diagnostic values were sensitivity of 0.83 (95% CI: 0.73-0.90), specificity of 0.95 (95%CI: 0.89-0.98), PLR of 17.8 (95%CI: 6.8-46.1), NLR of 0.17 (95%CI: 0.10-0.30), DOR of 102 (95%CI: 28-379), and AUC of 0.94 (95%CI: 0.91-0.96). In summary the overall diagnostic value of CSF EBV-DNA is very high and it can be a reliable diagnostic biomarker for AR-PCNSL.

Predicting Post-Stroke Cognitive Impairment Using Lesion Location

<h3>Research Objectives</h3> To develop a model to predict specific cognitive impairments following stroke based on the lesion's white matter edge density and location with respect to the left posterior arcuate fasciculus. <h3>Design</h3> Retrospective observational cohort study. <h3>Setting</h3> University medical center, inpatient and outpatient. <h3>Participants</h3> 149 adults (> 18 years old at time of stroke) from the Iowa Lesion Patient Registry. Participants must have had a stroke, an MRI or CT with visible focal brain lesion, and a neuropsychological assessment completed at the medical center. The cohort was 50% female, predominantly White (83%), upper middle-aged (mean age of 59 years old), and had an average of 13 years of education. <h3>Interventions</h3> Not applicable. <h3>Main Outcome Measures</h3> Cognitive impairment was quantified using z-scores for the following neuropsychological assessments, selected based on completion by >50% of participants Trail Making Test B, five subtests of the Wechsler Adult Intelligence Scale-IV, Benton Visual Retention Test, Rey Auditory Verbal Learning Test, Complex Figure Test, and two subtests of the Boston Diagnostic Aphasia Examination. The proportion of impaired tests per participant was also calculated. Lesion overlap with the left posterior arcuate fasciculus (LPAF) and lesion edge density were determined by summation of voxels. <h3>Results</h3> There was a significant though small positive correlation between the proportion of impaired z-scores and lesion overlap with the LPAF (r = 0.33, p <.001), indicating that greater lesion overlap corresponds to impairment on a greater number of neuropsychological test scores. The correlation between edge density and proportion of impaired scores was small and borderline significant (r=0.17, p=0.05). For individual neuropsychological tests, participants with lesion overlap to the LPAF had significantly lower scores than non-overlap participants on the majority (10 of 16) of assessed scores, and edge density was significantly negatively correlated to 7 of the 16 test scores. <h3>Conclusions</h3> Lesion overlap with the left posterior arcuate fasciculus has the potential to be used as a predictive marker of cognitive impairment in a post-stroke cohort and may be a stronger measure of cognitive impairment than edge density. <h3>Author(s) Disclosures</h3> No disclosures.

Diagnostic accuracy of magnetic resonance spectroscopy (MRS) for diagnosis of focal brain lesions taking histopathology as gold standard.

Objective: To determine diagnostic accuracy of MRS for diagnosis of malignant brain lesions taking histopathology as gold standard. Study Design: Cross Sectional Validation study. Setting: Department of Radiology, Lahore General Hospital, Lahore. Material &amp; Methods: A total number of 127 patients who were referred for the diagnosis of focal brain lesions were included. In all patients, MRS was done by consultant radiologist to diagnose malignancy. All patients underwent surgery in the neurosurgery department and after surgery biopsy specimen were taken for diagnosis of malignancy using histopathology findings. Results: Mean age of patients was 40.88±11.37 years. There were 88 (69.29%) males and 39 (30.71%) female patients. On MRS, malignancy was diagnosed in 99 (77.95%) patients and on histopathology malignancy was diagnosed in 102 (80.31%) patients. Regarding diagnostic accuracy, MRS was 97.00% sensitive, 94.10% specific, with PPV of 78.60% and NPV of 88.00%. Conclusion: Magnetic resonance spectroscopy (MRS) has good sensitivity and specificity in differentiating neoplasm from non-neoplastic focal brain lesions.

Network localization of transient global amnesia beyond the hippocampus.

Transient global amnesia is common in the older adult, but the cause and mechanism remain unclear. Focal brain lesions allow for causal links between the lesion location and resulting symptoms, and we based on the reported TGA-causing lesions and used lesion network mapping to explore the causal neuroanatomical substrate of TGA. Fifty-one cases of transient global amnesias with DWI lesions from the literature were identified, and clinical data were extracted and analyzed. Next, we mapped each lesion volume onto a reference brain and computed the network of regions functionally connected to each lesion location using a large normative connectome dataset. Lesions primarily occurred in the hippocampus, and in addition to the hippocampus, there are also other locations of TGA-causing lesions such as the cingulate gyrus, anterior thalamic nucleus (ATN), putamen, caudate nucleus, corpus callosum, fornix. More than 90% of TGA-causing lesions inside the hippocampus were functionally connected with the default mode network (DMN). Structural abnormality in the hippocampus was the most consistently reported in TGA, and besides the hippocampus, lesions occurring at several other brain locations also could cause TGA. The DMN may also be involved in the pathophysiology of TGA. According to the clinical and neuroimaging characteristics, TGA may be a syndrome with multiple causes and cannot be treated simply as a subtype of TIA.

Large-scale lesion symptom mapping of depression identifies brain regions for risk and resilience.

Understanding neural circuits that support mood is a central goal of affective neuroscience, and improved understanding of the anatomy could inform more targeted interventions in mood disorders. Lesion studies provide a method of inferring the anatomical sites causally related to specific functions, including mood. Here, we performed a large-scale study evaluating the location of acquired, focal brain lesions in relation to symptoms of depression. Five hundred and twenty-six individuals participated in the study across two sites (356 male, average age 52.4 ± 14.5 years). Each subject had a focal brain lesion identified on structural imaging and an assessment of depression using the Beck Depression Inventory-II, both obtained in the chronic period post-lesion (>3 months). Multivariate lesion-symptom mapping was performed to identify lesion sites associated with higher or lower depression symptom burden, which we refer to as 'risk' versus 'resilience' regions. The brain networks and white matter tracts associated with peak regional findings were identified using functional and structural lesion network mapping, respectively. Lesion-symptom mapping identified brain regions significantly associated with both higher and lower depression severity (r = 0.11; P = 0.01). Peak 'risk' regions include the bilateral anterior insula, bilateral dorsolateral prefrontal cortex and left dorsomedial prefrontal cortex. Functional lesion network mapping demonstrated that these 'risk' regions localized to nodes of the salience network. Peak 'resilience' regions include the right orbitofrontal cortex, right medial prefrontal cortex and right inferolateral temporal cortex, nodes of the default mode network. Structural lesion network mapping implicated dorsal prefrontal white matter tracts as 'risk' tracts and ventral prefrontal white matter tracts as 'resilience' tracts, although the structural lesion network mapping findings did not survive correction for multiple comparisons. Taken together, these results demonstrate that lesions to specific nodes of the salience network and default mode network are associated with greater risk versus resiliency for depression symptoms in the setting of focal brain lesions.

Changes in the structure of synaptic intercellular contacts in focal brain lesions

Purpose: to evaluate changes in the structure of synaptic contacts in various types of focal brain pathology. Materials and methods. The results of treatment of 40 cases of supratentorial focal lesions of the brain (FLB) were retrospectively evaluated. The cases are divided into groups: 30 gliomas of various degrees of malignancy and 5 consequences of TBI, 5 epilepsy. All patients underwent surgical interventions. The synaptic plasticity of axo-dendritic and axo-spiny asymmetric synapses of neurons of the VI-VII layers of the frontotemporal cortex was studied by electron microscopy. Morphometric analysis was carried out on a computer image analyzer САИ-01АВН using the software "Kappa opto-electronics GmbH" using the STATISTICA 7 program package. The results. It was established that the density of synapses decreased in glioblastomas (GB) and craniocerebral injury (ССІ). Qualitative changes demonstrate the plasticity of architectonics of synapse, in particular due to the increase in the number of perforated synaptic contacts. Maximum thickening and diffuse stratification of the postsynaptic seal indicates a violation of the functional capacity of the postsynaptic component of the contacts. A decrease in the number of synaptic vesicles was revealed in ССІ and GB, with their rearrangement, which is probably a manifestation of synaptic dysfunction. The latter proves the irreversibility of destructive local changes and is unfavorable criterion. The risk of the formation of destructive-degenerative changes in the synaptic apparatus is 7.64 times higher in DA, 3.17 times higher in GB, and 17.31 times higher in ССІ compared to cases of epilepsy, with GB significantly increases by 13.5 times compared to DA. Therefore, the assessment of the structural features of neuroplasticity should take into account the morphogenesis of the BM in comparison with clinical data Conclusions. In the zones of invasive growth of gliomas of various degrees of malignancy and in ССІ and epilepsy, the indicators of synaptic plasticity differ statistically significantly. The density of placement of synapses is lower in GB and ССІ. The probability of non-reversibility of destructive-degenerative changes of synapses according to the number of SVs in FLB correlates with the degree of glioma differentiation with a sensitivity of 81.0% and a specificity of 76.0%. According to the structural changes of synaptic connections in tumors, probable differences between the variants have been proven: GB and DA, the sensitivity of the discriminant model is 85.0%, the specificity is 74.0%, which is an indirect evidence of the growth rate of the tumor mass and its destructive effect on the surrounding brain matter. The obtained results are important in assessing the prognosis of the further course of the disease.

Treatment of Infantile Spasm Syndrome: Update from the Interdisciplinary Guideline Committee Coordinated by the German-Speaking Society of Neuropediatrics.

The manuscript serves as an update on the current management practices for infantile spasm syndrome (ISS). It includes a detailed summary of the level of current evidence of different treatment options for ISS and gives recommendations for the treatment and care of patients with ISS. A literature search was performed using the Cochrane and Medline Databases (2014 to July 2020). All studies were objectively rated using the Scottish Intercollegiate Guidelines Network. For recommendations, the evidence from these studies was combined with the evidence from studies used in the 2014 guideline. If ISS is suspected, electroencephalography (EEG) should be performed within a few days and, if confirmed, treatment should be initiated immediately. Response to first-line treatment should be evaluated clinically and electroencephalographically after 14 days. The preferred first-line treatment for ISS consists of either hormone-based monotherapy (AdrenoCorticoTropic Hormone [ACTH] or prednisolone) or a combination of hormone and vigabatrin. Children with tuberous sclerosis complex and those with contraindications against hormone treatment should be treated with vigabatrin. If first-line drugs are ineffective, second-line treatment options such as ketogenic dietary therapies, sulthiame, topiramate, valproate, zonisamide, or benzodiazepines should be considered. Children refractory to drug therapy should be evaluated early for epilepsy surgery, especially if focal brain lesions are present. Parents should be informed about the disease, the efficacy and adverse effects of the medication, and support options for the family. Regular follow-up controls are recommended.

Central precuneus lesions are associated with impaired executive function.

The functional roles of the precuneus are unclear. Focal precuneus lesions are rare, making it difficult to identify robust brain-behavior relationships. Distinct functional subdivisions of the precuneus have been proposed based on unique connectivity profiles. This includes an association of the anterior division with bodily awareness, the central region with complex cognition, and the posterior division with visual processing. Our goal was to test the hypothesis that the central precuneus is preferentially involved (compared to the other sectors of the precuneus) in executive function, as estimated from performance on the trail-making test (TMT). 35 patients with focal brain lesions involving the precuneus were included from the University of Iowa and Montpellier University. Multivariate lesion symptom mapping of TMT performance was performed to evaluate whether lesion location was associated with impaired task performance. Lesion symptom mapping revealed a statistically significant association of central precuneus lesions with impaired TMT performance (r = 0.43, p < 0.01). Further, a functional network derived from this precuneus region showed connectivity to other cortical areas implicated in executive function, including the dorsolateral prefrontal cortex and inferior parietal lobe. This analysis provides support for the role of the central precuneus in executive function, consistent with the unique connectivity pattern of the central precuneus with a broader network implicated in cognitive control and executive function.

Depression symptoms in neurological patients: A survey of a large cohort of patients with focal brain lesions

ABSTRACT Introduction Examining depression following neurological injury is useful for understanding post-lesion depression and depression more generally. The extant literature shows variability in the incidence and severity of depression post-lesion, likely due to heterogeneity in study methodology, patient samples, measures of depression, and time of assessment. Here, we aim to characterize depression symptoms and their demographic correlates in a large sample of individuals in the chronic epoch following a focal brain lesion. Method We sampled 492 individuals who had focal, stable brain lesions and were in the chronic epoch (≥3 months post-onset). Demographic (gender, years of education), temporal (age at lesion onset, time since lesion onset), and lesion (lesion laterality, lesion etiology, lesion volume) factors were used to predict depression symptoms measured by the Beck Depression Inventory (BDI). Results We found that on average, neurological patients exhibited elevated levels of depression symptoms (although not clinically significant) relative to a community sample, and the neurological patients showed higher rates of mild and moderate depression symptoms than are typical in a community sample. Gender and lesion etiology were predictive of depression symptoms, whereby women and patients with ischemic stroke had higher levels of depression symptoms. Conclusions Our results suggest that depression symptom severity may be elevated following a focal brain lesion. Moreover, some individuals may be more likely to develop depression symptoms post-lesion than others. This may be mediated by individual factors such as gender and lesion etiology. The findings have important implications for the diagnosis, prognosis, and treatment of depression in neurological patients.

Impaired neuronal integrity in traumatic brain injury detected by 123I-iomazenil single photon emission computed tomography and MRI

This study was aiming at investigating the extent of neuronal damage in cases of traumatic brain injury (TBI) with diffuse axonal injury (DAI) using 123I-iomazenil(IMZ) SPECT and MRI. We compared the findings in 31 patients with TBI without any major focal brain lesions and 25 age-matched normal controls. Subjects underwent 123I-IMZ SPECT and MRI, and also assessment by cognitive function tests. The partial volume effect of 123I-IMZ SPECT was corrected using MRI. In the patients with TBI, decreased spatial concentration of 123I-IMZ binding was detected in the medial frontal/orbitofrontal cortex, posterior cingulate gyrus, cuneus, precuneus, and superior region of the cerebellum. ROC analysis of 123I-IMZ SPECT for the detection of neuronal injury showed a high diagnostic ability of 123I-IMZ binding density for TBI in these areas. The decreased 123I-IMZ uptake density in the cuneus and precuneus was associated with cognitive decline after the injury. In the patients with TBI, brain atrophy was detected in the frontal lobe, anterior temporal and parietal cortex, corpus callosum, and posterior part of the cerebellum. Evaluation of the neuronal integrity by 123I-IMZ SPECT and MRI provides important information for the diagnosis and pathological interpretation in cases of TBI with DAI.

Academic skills after brain injury: A lifespan perspective.

This study investigated academic skills outcomes after brain injury and identified the influence of age and injury factors across the lifespan. Our sample included 651 participants with focal brain lesions. Math, reading, and spelling data from the Wide Range Achievement Test (WRAT) were used as the academic skills outcomes. Age of lesion onset ranged from 0 to 85 years old. Linear regressions were conducted to identify the relation between age and injury factors and academic skills outcomes. Lesion-symptom mapping was conducted to identify the brain areas that, when lesioned, were associated with deficits in academic skills. A quadratic model of age of lesion onset significantly predicted math (R² = .28, p < .001), reading (R² = .29, p < .001), and spelling outcomes (R² = .32, p < .001), while accounting for various covariates. Education, sex, lesion size and laterality, etiology, and seizure history were additional reliable predictors of academic skills outcomes across the lifespan. Academic skill deficits were associated with damage to various brain areas across the left-hemisphere frontal, temporal, and parietal lobes, the insular area, and left- and right-hemisphere white matter. This study supports age of lesion onset as a relevant predictor of academic skills after brain injury in a lifespan sample. Several other variables (e.g., education, sex, lesion characteristics, and seizure history) are notable in the prediction of outcomes across the lifespan. Future work could investigate more diverse samples and emphasize recruitment of early onset injuries to examine generalizability and potential critical periods for academic skills. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

MRI IN THE ASSESSMENT OF CEREBRAL INJURY AND CEREBROPROTECTIVE EFFECTS OF RENAL DENERVATION IN RESISTANT ARTERIAL HYPERTENSION

Objective: The purpose of this single-centre, prospective, comparative study was to evaluate the pattern and severity of the brain structural changes in patients with resistant hypertension (RH) based on MRI assessments and their changes one year after renal denervation (RDN). Design and method: The study comprised 58 patients with RH, aged 52.1 ± 9.1 years, who underwent RDN. Patients underwent office blood pressure measurements, 24-hour blood pressure monitoring, and brain MRI scanning. Using brain MRI, the cerebrospinal fluid (CSF) system measurements, the presence of periventricular leukoaraiosis and focal changes in the brain white matter were evaluated. Results: Initially, patients with RH had a high incidence of the structural brain alterations: 75% with fine focal brain lesions, 75% with impaired CSF dynamics, 23% with sulcal widening, and 90% with periventricular oedema. After RDN, a significant hypotensive effect was noted. According to brain MRI, the number of patients without impaired CSF dynamics did not change significantly: 25% initially, and 20% a year later (χ 2 = 0.63 p = 0.43, and χ2 = 0.72 p = 0.40). The number of patients with grade I impaired CSF dynamics after 6 months significantly increased after 12 months from 50% to 64% (χ2 = 4.00, p = 0.046) due to lowering the number of patients without impaired CSF dynamics and patients with grade II impaired CSF dynamics (χ2 = 1.56, p = 0.21). The number of patients with sulcal widening significantly decreased: from 23% to 8% one year following RDN (χ2 = 40.21 p = 0.000). The incidence of periventricular cerebral oedema did not significantly change one year after the procedure; however, the incidence of fine focal brain lesions significantly decreased (from 75 to 60%, p = 0.02). Conclusions: Thus, it has been revealed that patients with RH are characterised by a high incidence of structural brain alterations based on MRI assessments. A year after bilateral renal denervation, there are significant improvement in intracranial hypertension signs and decrease in the incidence of fine focal brain lesions, without a significant change in the CSF dynamics parameters (Table 1). Figure 1 shows a clinical example of a decrease in the number of fine focal brain lesions after the intervention.

That song in my head: a review on Musical Hallucinations

IntroductionHearing music inside our heads is frequent, however some hear it more vividly, constantly and involuntarily. Musical Hallucinations (MH), first described by Baillarger in 1846, are a complex type of auditory hallucination characterized by perception of melodies, music, or songs.ObjectivesThis work aims to review the literature considering MH.MethodsPubmed and Google Scholar search using MeSH term “musical hallucinations”ResultsMH occurs in 0.16% of the population. They´re usually perceived as frightening or annoying. Proposed mechanisms include spontaneous activity triggered by sensory deprivation from hearing impairment, like in visual hallucinations in Charles Bonnet syndrome, and some authors even include MH as a subtype of this syndrome. Indeed, 60% of all patients with MH have hearing impairment or deafness. Other less frequent causes include focal brain lesions involving the auditory pathway and cortex, temporal epilepsy, metabolic or drug intoxication. Psychiatric conditions are uncommon but not impossible, especially in affective disorders. MH most frequently consist in familiar tunes, sometimes of personal significance, religious songs (especially in older patients), childhood songs, folk and popular songs from the radio - suggesting that musical perception is never unlearned but represents a “parasitic memory”, an unchangeable memory feature which can be experienced by relevant neuronal circuit stimulation. Most patients with MH were reported to have no extraordinary musical skills.ConclusionsMH are rare and strongly associated with hearing loss, though investigation of other causes should be sought. Treating the underlying cause is important but remission is not guaranteed.DisclosureNo significant relationships.

A.4 Entropy on routine EEG: an interictal marker of seizure frequency?

Background: Sample entropy (SampEn) can quantify the unpredictability of a physiological signal. We sought to assess if SampEn on EEG could reflect recent seizure activity. Methods: Charts of all patients undergoing an outpatient EEG between January and March 2018 were reviewed to assess seizure occurrences in the follow-up period between the two clinical visits surrounding the EEG. 9s-EEG segments were extracted at pre-specified time points. SampEn was calculated for all segments and values aggregated at the 25thpercentile. We performed a multivariate zero-inflated analysis to test the association between SampEn and seizure rate around the EEG, after controlling for age, presence of IED, presence of abnormal slowing, and presence of a focal brain lesion. Results: 269 EEGs were screened and 133 met inclusion criteria (112 patients). 80 EEGs (60%) were from patients with epilepsy, of which 47 had at least one seizure within the year preceding the EEG. Remaining EEGs were from patients who were deemed not to have epilepsy at last follow-up. Each 1SD decrease in SampEn was associated with a 3.93-fold increase in the rate of daily seizures (95% CI: 1.19–12.99, p = 0.02). Conclusions: Sample entropy of EEG is a potential objective method to assess contemporary seizure occurrence.

Diagnostic Accuracy of Diffusion Weighted MRI in Diagnosing Brain Abscess Taking Histopathology as Gold Standard

Aim: Diagnostic accuracy of DW-MRI in diagnosing brain abscess taking histopathology as gold standard. Methodology: A total of 407 patients having focal brain lesion on MRI of age 20-50 years of either gender were included. Patients with history of brain surgery, already established diagnosis on histopathology, claustrophobia and pregnant or breast feeding females were excluded. DW-MRI was done and conventional MRI sequences on 1.5 tesla MRI machine and presence or absence of brain abscess was noted. DW-MRI findings were correlated with histopathology. Results: Mean age was 38.53 ± 7.59 years. Out of these 407 patients, 262 (64.37%) were male and 145 (35.63%) were females with ratio of 1.8:1. Mean duration of disease was 4.87 ± 2.40 months. Mean size of lesion was 7.69 ± 4.52 mm. In DW-MRI positive patients, 221 were true positive and 32 were false positive. Among 154, DW-MRI negative patients, 18 were false negative whereas 136 were true negative (P-value=0.01). So in diagnosis of abscess in brain, sensitivity, specificity, PPV, NPV and DA of DW-MRI was 92.5%, 80.96%, 87.4%, 88.3% and 87.7% respectively. Conclusion: DW-MRI is the non-invasive modality of choice having high diagnostic accuracy (DA) i.. 87.7% in diagnosing brain abscess with sensitivity of 92.5% and specificity of 80.96%. Keywords: Brain abscess, diffusion weighted imaging, sensitivity.

The effect of lesion filling on brain network analysis in multiple sclerosis using structural magnetic resonance imaging

BackgroundGraph theoretical network analysis with structural magnetic resonance imaging (MRI) of multiple sclerosis (MS) patients can be used to assess subtle changes in brain networks. However, the presence of multiple focal brain lesions might impair the accuracy of automatic tissue segmentation methods, and hamper the performance of graph theoretical network analysis. Applying “lesion filling” by substituting the voxel intensities of a lesion with the voxel intensities of nearby voxels, thus creating an image devoid of lesions, might improve segmentation and graph theoretical network analysis. This study aims to determine if brain networks are different between MS subtypes and healthy controls (HC) and if the assessment of these differences is affected by lesion filling.MethodsThe study included 49 MS patients and 19 HC that underwent a T1w, and T2w-FLAIR MRI scan. Graph theoretical network analysis was performed from grey matter fractions extracted from the original T1w-images and T1w-images after lesion filling.ResultsArtefacts in lesion-filled T1w images correlated positively with total lesion volume (r = 0.84, p < 0.001) and had a major impact on grey matter segmentation accuracy. Differences in sensitivity for network alterations were observed between original T1w data and after application of lesion filling: graph theoretical network analysis obtained from lesion-filled T1w images produced more differences in network organization in MS patients.ConclusionLesion filling might reduce variability across subjects resulting in an increased detection rate of network alterations in MS, but also induces significant artefacts, and therefore should be applied cautiously especially in individuals with higher lesions loads.

Comparison of Qualitative and Quantitative Analyses of MR-Arterial Spin Labeling Perfusion Data for the Assessment of Pediatric Patients with Focal Epilepsies.

The role of MR Arterial-Spin-Labeling Cerebral Blood Flow maps (ASL-CBF) in the assessment of pediatric focal epilepsy is still debated. We aim to compare the Seizure Onset Zone (SOZ) detection rate of three methods of evaluation of ASL-CBF: 1) qualitative visual (qCBF), 2) z-score voxel-based quantitative analysis of index of asymmetry (AI-CBF), and 3) z-score voxel-based cluster analysis of the quantitative difference of patient’s CBF from the normative data of an age-matched healthy population (cCBF). Interictal ASL-CBF were acquired in 65 pediatric patients with focal epilepsy: 26 with focal brain lesions and 39 with a normal MRI. All hypoperfusion areas visible in at least 3 contiguous images of qCBF analysis were identified. In the quantitative evaluations, clusters with a significant z-score AI-CBF ≤ −1.64 and areas with a z-score cCBF ≤ −1.64 were considered potentially related to the SOZ. These areas were compared with the SOZ defined by the anatomo-electro-clinical data. In patients with a positive MRI, SOZ was correctly identified in 27% of patients using qCBF, 73% using AI-CBF, and 77% using cCBF. In negative MRI patients, SOZ was identified in 18% of patients using qCBF, in 46% using AI-CBF, and in 64% using cCBF (p < 0.001). Quantitative analyses of ASL-CBF maps increase the detection rate of SOZ compared to the qualitative method, principally in negative MRI patients.