Magnetic Resonance Imaging MRI Research Articles

Acute Disseminated Encephalomyelitis Secondary to Herpes Virus Infection in a Child

The acute disseminated encephalomyelitis ADEM is a rare form of encephalitis. We report a case after herpes infection. The diagnosis was based on the existence of post-infectious and neurological signs and demyelinating reaching the white matter in the magnetic resonance imaging MRI. The outcome was favourable after treatment with high-dose steroids.

MRI Brain Findings in Adults with Lesional Refractory Epilepsy and Correlation to Surgical Outcome

Introduction: Refractory epilepsy which is defined as failure of adequate trials of two tolerated, appropriately chosen and used antiepileptic drug schedules (whether as monotherapies or in combination) to achieve sustained seizure freedom is common in patients with structural brain lesions including acquired disorders and genetic abnormalities. High resolution Magnetic Resonance Imaging MRI of the brain has proven its precision as a diagnostic tool for recognition of different structural lesions underlying medically intractable seizures. Objective: To recognize common MRI lesions in a series of adult patients with refractory epilepsy admitted to the epilepsy monitoring unit at Prince Sultan Military Medical City PSMMC for pre surgical evaluation for epilepsy surgery with correlation to surgical outcome and to compare our local data with the international literature. Material and methods: 245 patients (100 Males and 145 Females; 14-53 years) with refractory epilepsy were included in this retrospective analysis. They presented with partial with or without complex partial seizures 112 (46.0%), partial with secondary generalized tonic clonic seizures 76 (31.0%) or generalized seizures in 57 (23.0%) of patients. Clinical diagnosis of epilepsy and seizure classification were based on the revised criteria of the International League Against Epilepsy ILAE. Structural neuroimaging MRI brain, functional neuroimaging which include Interictal Fluorodeoxyglucose Positron Emission Computed Tomography FDG-PET, Ictal Technetium-99m hexamethyl-propylene amine oxime Single Photon Emission Computed Tomography 99 m HMPAO SPECT, Electroencephalography EEG recording, epilepsy history and neurological examination were performed. MRI brain imaging epilepsy protocol used a 1.5 or 3 Tesla MRI scanner. All patients included in this study received appropriate epilepsy surgery and post-operative seizure control was followed in the epilepsy clinic with six-month post-operative inter ictal EEG, follow up MRI brain after epilepsy surgery were performed in all patients and 50 patients had additional video-EEG recording postoperative during the follow up period. Epilepsy surgery seizure control outcome was classified according to Engel Classification system. All patients were followed for at least two years post-operatively to assess seizure control. Pre-operative MRI diagnosis was correlated with the epilepsy surgery seizure control outcome. Results: MRI detected different structural brain abnormalities in 245 (100%) patients, including temporal lobe location in 142 (58%) patients, frontal lobe location in 74 (30%) patients and parieto-occipital lobes location in 29 (12%) patients. On MRI hippocampal sclerosis HS is diagnosed in 86 (35%) patients, cerebral tumors in 74 (30%) patients and among the cerebral tumors MRI suggested the diagnosis of developmental tumors that is; glio-neural tumors in 45 out of 74 (61%) of tumor patients, malformations of cortical development MCD in 42 (17%) patients, vascular malformations in 15 (6%) patients, dual pathologies in 12 (5%) patients and remote gliotic lesions in 16 (7%) patients. The histopathological diagnosis confirmed the MRI brain diagnosis in all included patients. At 2 years of post-operative follow-up 196 (80%) patients were classified as Engel Class I, 37 (15%) patients Engel Class II, 6 (3%) patients Engel Class III and 6 (3%) patients as Class IV seizure freedom. In the class IV group two patients failed epilepsy surgery because they had high grade astrocytoma with postoperative tumor recurrence and four patients failed epilepsy surgery due to incomplete resection of epileptogenic lesions. Patients with MRI diagnosis of HS 82 out of 86 (95%) patients, low grade tumor 59 out of 74 (80%) patients and vascular malformation 12 out of 15 (80%) had best epilepsy surgery outcome. Patients with high grade tumors 2 out 3 (67%) patients and incomplete surgical resection of epileptogenic lesions 4 out of 5 (80%) patients had the worst epilepsy surgery outcome. Conclusion: This study revealed that MRI brain structural lesions were commonly associated with refractory epilepsy. Temporal lobe structural brain lesions were most common lesions in adult epilepsy patients with refractory epilepsy referred for epilepsy surgery. The presence of HS, low grade tumors and vascular malformations correlated with best surgical outcome while high grade tumors and incomplete surgical resection of the lesions correlated with worst surgical outcome. Our results were consistent with the international reported literature.

In Vivo Identification of Thick, Thin, and Pale Stripes of Macaque Area V2 Using Submillimeter Resolution (f)MRI at 3 T.

Primate area V2 contains a repetitive pattern of thick, thin and pale cytochrome oxidase stripes that are characterized by largely discrete in- and output channels, as well as differences in function, and myelo- and cytoarchitecture. Stripes have been identified mainly using microscope-based imaging of tiny portions of superficially located V2, or by postmortem methods, hence, the quest for (quasi) noninvasive tools to study these mesoscale functional units. Only recently, stripe-like V2 patterns have been demonstrated in humans with high-field (functional) magnetic resonance imaging (f)MRI, but in both such studies only 2 stripe compartments could be identified. Although interstripe distances in monkeys are ~half of those in humans, we show that all 3 V2 stripe classes can be reliably separated using submillimeter (f)MRI (0.6 mm isotropic voxels) on regular 3 T scanners by combining contrast agents and implanted phased-array coils. Specifically, we show highly reproducible fMRI patterns, both within and across subjects, of color-selective thin and disparity-selective thick stripes. Furthermore, reliable MRI-based higher myelin-density was observed in pale stripes. Hence, this is the first study showing segregation of columns using (f)MRI-based methods in macaque cortex, which opens the possibility of studying these elementary building blocks of the visual system noninvasively on a large scale.

Diagnostic Values of DCE-MRI and DSC-MRI for Differentiation Between High-grade and Low-grade Gliomas: A Comprehensive Meta-analysis

This study aimed to collect the studies on the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and dynamic susceptibility contrast MRI (DSC-MRI) in differentiating the grades of gliomas, and evaluate the diagnostic performances of relevant quantitative parameters in glioma grading. We systematically searched studies on the diagnosis of gliomas with DCE-MRI or DSC-MRI in Medline, PubMed, China National Knowledge Infrastructure database, Cochrane Library, and Embase published between January 2005 and December 2016. Standardized mean differences and 95% confidence intervals were calculated for volume transfer coefficient (Ktrans), volume fraction of extravascular extracellular space (Ve), rate constant of backflux (Kep), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) using Review Manager 5.2 software. Sensitivity, specificity, area under the curve (AUC), and Begg test were calculated by Stata 12.0. Twenty-two studies with available outcome data were included in the analysis. The standardized mean difference of Ktrans values between high-grade glioma and low-grade glioma were 1.18 (0.91, 1.45); Ve values were 1.43 (1.06, 1.80); Kep values were 0.65 (-0.05, 1.36); rCBV values were 1.44 (1.08, 1.81); and rCBF values were 1.17 (0.68, 1.67), respectively. The results were all significant statistically (P < .05) except Kep values (P = .07), and high-grade glioma had higher Ktrans, Ve, rCBV, and rCBF values than low-grade glioma. AUC values of Ktrans, Ve, rCBV, and rCBF were 0.90, 0.88, 0.93, and 0.73, respectively; rCBV had the largest AUC among the four parameters (P < .05). Both DCE-MRI and DSC-MRI are reliable techniques in differentiating the grades of gliomas, and rCBV was found to be the most sensitive one.

Etiology of isolated pontine infarctions: a study based on high-resolution MRI and brain small vessel disease scores

BackgroundIn this retrospective study, we investigated the main pathogenesis of the two types of isolated pontine infarction: paramedian pontine infarcts (PPIs) and small deep pontine infarcts (SDPIs).MethodsAcute ischemic stroke patients, comprising 117 PPI patients and 40 SDPI patients, were enrolled. High-resolution magnetic resonance imaging (HR-MRI) and routine MRI sequences were performed for each patient, and clinical data were collected. The following brain small vessel disease (SVD) features of the MRI scans were each rated (0 or 1) separately: asymptomatic lacunar infarcts, white matter lesions (WMLs), deep and infratentorial cerebral microbleeds (CMBs), and enlarged perivascular spaces in the basal ganglia. The ratings were also summed in an ordinal “SVD score” (range: 0–4). The difference in the SVD score between the PPI and SDPI groups was determined. The presence and location of basilar artery (BA) atherosclerotic plaques (based on HR-MRI) in the two groups was evaluated.ResultsThere was a significant difference in the total SVD score and three of the four independent SVD features (asymptomatic lacunar infarcts, WMLs, and deep and infratentorial CMBs) between the two groups. The prevalence of BA plaques relevant to the infarcts in the PPI group was significantly higher than that in the SDPI group, whereas the prevalence of plaques irrelevant to the infarcts was similar between the two groups. The degree of BA stenosis was slightly higher in the PPI group than in the SDPI group. Diabetes mellitus was much more prevalent in the PPI group. The National Institute of Health Stroke Scale score was higher in the PPI group, which is in accordance with the larger infarct size in the PPI group.ConclusionBA atherosclerosis may be the major cause of PPI, while SVD may be the main mechanism underlying SDPI. HR-MRI combined with the total SVD score should be helpful to explore the pathogenesis underlying isolated pontine infarctions, especially in cases involving low-grade BA stenosis.

Dynamic contrast-enhanced magnetic resonance imaging and diffusion-weighted magnetic resonance imaging for predicting the response of locally advanced breast cancer to neoadjuvant therapy: a meta-analysis.

.This meta-analysis assesses the prognostic value of quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) performed during neoadjuvant therapy (NAT) of locally advanced breast cancer. A systematic literature search was conducted to identify studies of quantitative DCE-MRI and DW-MRI performed during breast cancer NAT that report the sensitivity and specificity for predicting pathological complete response (pCR). Details of the study population and imaging parameters were extracted from each study for subsequent meta-analysis. Metaregression analysis, subgroup analysis, study heterogeneity, and publication bias were assessed. Across 10 studies that met the stringent inclusion criteria for this meta-analysis (out of 325 initially identified studies), we find that MRI had a pooled sensitivity of 0.91 [95% confidence interval (CI), 0.80 to 0.96] and specificity of 0.81(95% CI, 0.68 to 0.89) when adjusted for covariates. Quantitative DCE-MRI exhibits greater specificity for predicting pCR than semiquantitative DCE-MRI (). Quantitative DCE-MRI and DW-MRI are able to predict, early in the course of NAT, the eventual response of breast tumors, with a high level of specificity and sensitivity. However, there is a high degree of heterogeneity in published studies highlighting the lack of standardization in the field.

Diagnostic value of cone beam computed tomography (CBCT) in occult scaphoid and wrist fractures

ObjectiveEvaluate the diagnostic value of cone beam computed tomography (CBCT) for scaphoid and wrist fractures that are missed on standard radiographs. Materials and methodsBetween September 2014 and October 2015, we prospectively enrolled 49 patients with a clinically suspected scaphoid fracture following an acute injury but had normal radiographs. Each patients underwent radiographs, CBCT and (magnetic resonance imaging) MRI within 7days of the initial injury event. Both exam were evaluated independently by two radiologists. ResultsFor scaphoid cortical fractures CBCT sensitivity is 100% (95% CI: 75%–100%), specificity 97% (95% CI: 83%–100%). CBCT diagnosed all 24 corticals wrist fractures, corresponding to a sensitivity of 100% (95% CI: 83%–100%), specificity of 95% (95% CI: 75%–100%). Kappa agreement rate between the two radiologists was K=0.95 (95% CI: 0.85–1) for scaphoid fractures and K=0.87 (95% CI: 0.73–1) for wrist fractures. ConclusionsCBCT is superior to radiographs for diagnosing occult cortical fractures. Because of its low radiation dose, we believe that CBCT can be used in current practice as a replacement or supplement to radiographs to detect these fractures and optimize the cost-effectiveness ratio by limiting the number of needless immobilizations.

Whole body magnetic resonance imaging (WB-MRI) and brain MRI baseline surveillance in TP53 germline mutation carriers: experience from the Li-Fraumeni Syndrome Education and Early Detection (LEAD) clinic.

Individuals with Li-Fraumeni syndrome (LFS) have a significantly increased lifetime cancer risk affecting multiple organ sites. Therefore, novel comprehensive screening approaches are necessary to improve cancer detection and survival in this population. The objective of this study was to determine the diagnostic performance of whole body MRI (WB-MRI) and dedicated brain MRI screening as part of a comprehensive screening clinic called Li-Fraumeni Education and Early Detection (LEAD) at MD Anderson Cancer Center. Adult (≥21year old) and pediatric (<21year old) patients were referred to the LEAD clinic by healthcare providers or self-referred and screened at 6month intervals. During the study period, 63 LFS individuals were seen in the LEAD clinic including 49 adults (11 male, 38 female) and 14 children (7 male, 7 female). Fifty-three of 63 potentially eligible individuals underwent baseline WB-MRI (41 adults and 12 children) with primary tumors detected in six patients, tumor recurrence in one patient and cancer metastases in one patient. Thirty-five of 63 patients (24 adults and 11 children) underwent baseline brain MRI with primary brain tumors detected in three individuals, also noted on subsequent WB-MRI scans. Three additional tumors were diagnosed that in retrospect review were missed on the initial scan (false negatives) and one tumor noted, but not followed up clinically, was prospectively found to be malignant. The high incidence of asymptomatic tumors identified in this initial screening (13%), supports the inclusion of WB-MRI and brain MRI in the clinical management of individuals with LFS.

DCE- and DW-MRI as early imaging biomarkers of treatment response in a preclinical model of triple negative breast cancer.

This work evaluates quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) parameters as early biomarkers of response in a preclinical model of triple negative breast cancer (TNBC). The standard Tofts' model of DCE-MRI returns estimates of the volume transfer constant (Ktrans ) and the extravascular extracellular volume fraction (ve ). DW-MRI returns estimates of the apparent diffusion coefficient (ADC). Mice (n=38) were injected subcutaneously with MDA-MB-231. Tumors were grown to approximately 275mm3 and sorted into the following groups: saline controls, low-dose Abraxane (15mg/kg) and high-dose Abraxane (25mg/kg). Animals were imaged at days zero, one and three. On day three, tumors were extracted for immunohistochemistry. The positive percentage change in ADC on day one was significantly higher in both treatment groups relative to the control group (p<0.05). In addition, the positive percentage change in Ktrans was significantly higher than controls (p<0.05) on day one for the high-dose group and on days one and three for the low-dose group. The percentage change in tumor volume was significantly different between the high-dose and control groups on day three (p=0.006). Histology confirmed differences at day three through reduced numbers of proliferating cells (Ki67 staining) in the high-dose group (p=0.03) and low-dose group (p=0.052) compared with the control group. Co-immunofluorescent staining of vascular maturity [using von Willebrand Factor (vWF) and α-smooth muscle actin (α-SMA)] indicated significantly higher vascular maturation in the low-dose group compared with the controls on day three (p=0.03), and trending towards significance in the high-dose group compared with controls on day three (p=0.052). These results from quantitative imaging with histological validation indicate that ADC and Ktrans have the potential to serve as early biomarkers of treatment response in murine studies of TNBC.

Diffusion MRI and the detection of alterations following traumatic brain injury.

This article provides a review of brain tissue alterations that may be detectable using diffusion magnetic resonance imaging MRI (dMRI) approaches and an overview and perspective on the modern dMRI toolkits for characterizing alterations that follow traumatic brain injury (TBI). Noninvasive imaging is a cornerstone of clinical treatment of TBI and has become increasingly used for preclinical and basic research studies. In particular, quantitative MRI methods have the potential to distinguish and evaluate the complex collection of neurobiological responses to TBI arising from pathology, neuroprotection, and recovery. dMRI provides unique information about the physical environment in tissue and can be used to probe physiological, architectural, and microstructural features. Although well‐established approaches such as diffusion tensor imaging are known to be highly sensitive to changes in the tissue environment, more advanced dMRI techniques have been developed that may offer increased specificity or new information for describing abnormalities. These tools are promising, but incompletely understood in the context of TBI. Furthermore, model dependencies and relative limitations may impact the implementation of these approaches and the interpretation of abnormalities in their metrics. The objective of this paper is to present a basic review and comparison across dMRI methods as they pertain to the detection of the most commonly observed tissue and cellular alterations following TBI.

Extraskeletal and Skeletal Ewing Sarcoma Family of Tumours in Adults: A Clinico Radiological Review of 50 Cases

This review describes the imaging characteristics of Ewing sarcoma family of tumours ESFT exclusively in an adult population The magnetic resonance imaging MRI and computed tomography CT appearances in adult patients with ESFT is described The imaging characteristics in this largest case series of adult ESFT reported so far were similar to those reported in the paediatric ESFT Our incidence of extra skeletal ESFT of is the highest reported so far in the adult population and is higher than the reported incidence of in the paediatric and adolescent population MRI was found to be superior to CT scan in identifying tumour involvement of the bone marrow and in delineating the soft tissue involvement due to its multi planar imaging capability

Analysing the Use of EEG, fMRI, PET and Behavioural Studies of Brain Lesioned Patients Associated with Non-Literal Language e.g. Metaphors, Sarcasm, Some Types of Humour Etc.

The purpose of this review is to document the findings conducted via techniques such as EEG (ElectroEncephaloGram), fMRI (Functional Magnetic Resonance Imaging or functional MRI), PET (brain Positron Emission Tomography) and behavioral studies used to study brain-processing in comprehension of non-literal language in patients with brain lesions. There have been several studies to locate the comprehension of non-literal language in patients with brain lesions with differing conclusions over the years. To suggest a way forward, the lacunae in each method is examined and a solution suggested by combining theoretical approaches and technological advances to better understand brain functioning in comprehension of non-literal language.

Sentinel node necrosis is a negative prognostic factor in patients with nasopharyngeal carcinoma: a magnetic resonance imaging study of 252 patients.

We explored the patterns of sentinel node metastasis and investigated the prognostic value of sentinel node necrosis (snn) in patients with nasopharyngeal carcinoma (npc), based on magnetic resonance imaging (mri). This retrospective study enrolled 252 patients at our institution who had metastatic lymph nodes from biopsy-confirmed npc and who were treated with definitive radiation therapy, with or without chemotherapy. All participants underwent mri before treatment, and the resulting images were reviewed to evaluate lymph node status. The patients were divided into snn and non-snn groups. Overall survival (os), tumour-free survival (tfs), regional relapse-free survival (rrfs), and distant metastasis-free survival (dmfs) were calculated by the Kaplan-Meier method, and differences were compared using the log-rank test. Factors predictive of outcome were determined by univariate and multivariate analysis. Of the 252 patients, 189 (75%) had retropharyngeal lymph node metastasis, and 189 (75%) had level iia or iib lymph node necrosis. The incidence of snn was 43.4% (91 of 210 patients with lymph node metastasis or necrosis, or both). After a median follow-up of 54 months, the 5-year rates of os, tfs, rrfs, and dmfs in the snn and non-snn groups were, respectively, 79.4% and 95.3%, 73.5% and 93.3%, 80.4% and 96.6%, and 75.5% and 95.3% (all p < 0.01). Age greater than 40 years, snn, T stage, and N stage were significant independent negative prognostic factors for os, tfs, rrfs, and dmfs. Metastatic retropharyngeal lymph nodes and necrotic level ii nodes both seem to act as sentinels. Sentinel node necrosis is an negative prognostic factor in patients with npc. Patients with snn have a worse prognosis.

Accuracy of PDFF estimation by magnitude-based and complex-based MRI in children with MR spectroscopy as a reference.

To assess and compare the accuracy of magnitude-based magnetic resonance imaging (MRI-M) and complex-based MRI (MRI-C) for estimating hepatic proton density fat fraction (PDFF) in children, using MR spectroscopy (MRS) as the reference standard. A secondary aim was to assess the agreement between MRI-M and MRI-C. This was a HIPAA-compliant, retrospective analysis of data collected in children enrolled in prospective, Institutional Review Board (IRB)-approved studies between 2012 and 2014. Informed consent was obtained from 200 children (ages 8-19 years) who subsequently underwent 3T MR exams that included MRI-M, MRI-C, and T1 -independent, T2 -corrected, single-voxel stimulated echo acquisition mode (STEAM) MRS. Both MRI methods acquired six echoes at low flip angles. T2*-corrected PDFF parametric maps were generated. PDFF values were recorded from regions of interest (ROIs) drawn on the maps in each of the nine Couinaud segments and three ROIs colocalized to the MRS voxel location. Regression analyses assessing agreement with MRS were performed to evaluate the accuracy of each MRI method, and Bland-Altman and intraclass correlation coefficient (ICC) analyses were performed to assess agreement between the MRI methods. MRI-M and MRI-C PDFF were accurate relative to the colocalized MRS reference standard, with regression intercepts of 0.63% and -0.07%, slopes of 0.998 and 0.975, and proportion-of-explained-variance values (R2 ) of 0.982 and 0.979, respectively. For individual Couinaud segments and for the whole liver averages, Bland-Altman biases between MRI-M and MRI-C were small (ranging from 0.04 to 1.11%) and ICCs were high (≥0.978). Both MRI-M and MRI-C accurately estimated hepatic PDFF in children, and high intermethod agreement was observed. 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1641-1647.

Structured and Sparse Canonical Correlation Analysis as a Brain-Wide Multi-Modal Data Fusion Approach.

Multi-modal data fusion has recently emerged as a comprehensive neuroimaging analysis approach, which usually uses canonical correlation analysis (CCA). However, the current CCA-based fusion approaches face problems like high-dimensionality, multi-collinearity, unimodal feature selection, asymmetry, and loss of spatial information in reshaping the imaging data into vectors. This paper proposes a structured and sparse CCA (ssCCA) technique as a novel CCA method to overcome the above problems. To investigate the performance of the proposed algorithm, we have compared three data fusion techniques: standard CCA, regularized CCA, and ssCCA, and evaluated their ability to detect multi-modal data associations. We have used simulations to compare the performance of these approaches and probe the effects of non-negativity constraint, the dimensionality of features, sample size, and noise power. The results demonstrate that ssCCA outperforms the existing standard and regularized CCA-based fusion approaches. We have also applied the methods to real functional magnetic resonance imaging (fMRI) and structural MRI data of Alzheimer's disease (AD) patients (n = 34) and healthy control (HC) subjects (n = 42) from the ADNI database. The results illustrate that the proposed unsupervised technique differentiates the transition pattern between the subject-course of AD patients and HC subjects with a p-value of less than 1×10-6 . Furthermore, we have depicted the brain mapping of functional areas that are most correlated with the anatomical changes in AD patients relative to HC subjects.

Conflating Capacity & Authority: Why We're Asking the Wrong Question in the Adolescent Decision-Making Debate.

Whether adolescents should be allowed to make their own medical decisions has been a topic of discussion in bioethics for at least two decades now. Are adolescents sufficiently capacitated to make their own medical decisions? Is the mature-minor doctrine, an uncommon legal exception to the rule of parental decision-making authority, something we should expand or eliminate? Bioethicists have dealt with the curious liminality of adolescents-their being neither children nor adults-in a variety of ways. However, recently there has been a trend to rely heavily, and often exclusively, on emerging neuroscientific and psychological data to answer these questions. Using data from magnetic resonance imaging and functional MRI studies on the adolescent brain, authors have argued both that the adolescent brain isn't sufficiently mature to broadly confer capacity on this population and that the adolescent brain is sufficiently mature to assume adolescent capacity. Scholars then accept these data as sufficient for concluding that adolescents should or should not have decision-making authority. Two critical mistakes are being made here. The first is the expectation that neuroscience or psychology is or will be able to answer all our questions about capacity. The second, and more concerning, mistake is the conflation of decision-making capacity with decision-making authority.

Osteochondroma-Related Distal Tibiofibular Synostosis with an Isolated Subtalar Joint Degeneration and Flexor Hallucis Longus Tendon Entrapment

Osteochondroma exostose related distal tibiofibular synostosis was noticed in a year old male patient with a previously known Hereditary Multiple Exostosis HME He had chronic complaints of right ankle pain with a hard shin swelling Radiography Computed Tomography CT and Magnetic Resonance Imaging MRI exams revealed an osteochondroma related distal tibiofibular synostosis complicated with subtalar joint arthritis and flexor hallucis longus tendon entrapment

Fully automatic method for segmentation of brain tumor from multimodal magnetic resonance images using wavelet transformation and clustering technique

Fully automatic brain tumor segmentation is one of the critical tasks in magnetic resonance imaging MRI images. This proposed work is aimed to develop an automatic method for brain tumor segmentation process by wavelet transformation and clustering technique. The proposed method using discrete wavelet transform DWT for pre- and post-processing, fuzzy c-means FCM for brain tissues segmentation. Initially, MRI images are preprocessed by DWT to sharpen the images and enhance the tumor region. It assists to quicken the FCM clustering technique and classified into four major classes: gray matter GM, white matter WM, cerebrospinal fluid CSF, and background BG. Then check the abnormality detection using Fuzzy symmetric measure for GM, WM, and CSF classes. Finally, DWT method is applied in segmented abnormal region of images respectively and extracts the tumor portion. The proposed method used 30 multimodal MRI training datasets from BraTS2012 database. Several quantitative measures were calculated and compared with the existing. The proposed method yielded the mean value of similarity index as 0.73 for complete tumor, 0.53 for core tumor, and 0.35 for enhancing tumor. The proposed method gives better results than the existing challenging methods over the publicly available training dataset from MICCAI multimodal brain tumor segmentation challenge and a minimum processing time for tumor segmentation. © 2016 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 26, 305-314, 2016

Language Functions in the Frontal Association Area: Brain Mechanisms That Create Language

Broca's area is known to be critically involved in language processing for more than 150 years. Recent neuroimaging techniques, including functional magnetic resonance imaging (fMRI) and diffusion MRI, enabled the subdivision of Broca's area based on both functional and anatomical aspects. Networks among the frontal association areas, especially the left inferior frontal gyrus (IFG), and other cortical regions in the temporal/parietal association areas, are also important for language-related information processing. Here, we review how neuroimaging studies, combined with research paradigms based on theoretical linguistics, have contributed to clarifying the critical roles of the left IFG in syntactic processing and those of language-related networks, including cortical and cerebellar regions.

Alterations in amygdala-prefrontal circuits in infants exposed to prenatal maternal depression.

Prenatal exposure to maternal depression is common and puts offspring at risk for developing a range of neuropsychiatric disorders. Despite its prevalence and adverse associations, neurobiological processes by which prenatal maternal depression (PMD) confers risk remain poorly understood. Maternal mood and fetal behavior were assessed between 34 and 37 gestational weeks. Using resting-state functional magnetic resonance imaging (fMRI) and diffusion MRI, we examined functional and structural connectivity within amygdala–prefrontal circuits in 64 infants (mean age=5.8±1.7 weeks) with (n=20) and without (n=44) in utero exposure to PMD. Resting fMRI and diffusion MRI both indicated atypical amygdala–prefrontal connectivity in PMD-exposed infants: Resting fMRI indicated increased inverse, or negative, functional connectivity between the amygdala and the dorsal prefrontal cortex (PFC), bilaterally, and diffusion MRI indicated decreased structural connectivity between the right amygdala and the right ventral PFC. Spectral dynamic causal modeling supported these findings suggesting altered amygdala–PFC effective (or directed) connectivity in PMD-exposed infants. Last, path analyses supported a mechanistic account relating PMD to a third-trimester fetal behavior: PMD alters amygdala–PFC connectivity, which in turn, is associated with an increase in fetal heart rate reactivity to in utero perturbation. These data suggest that the maturation and coordination of central and peripheral physiology are altered by prenatal exposure to maternal depression. To the best of our knowledge, this is the first study to directly associate infant MRI measures with a behavior—fetal heart rate response, and supports hypotheses that PMD-associated variations in the development of amygdala–PFC circuits are relevant for future neurobehavioral maturation.