Normal Magnetic Resonance Research Articles

Pivotal Role of Subcortical Structures as a Network Hub in Focal Epilepsy: Evidence from Graph Theoretical Analysis Based on Diffusion-Tensor Imaging.

Background and PurposeThere is accumulating evidence that epilepsy is caused by network dysfunction. We evaluated the hub reorganization of subcortical structures in patients with focal epilepsy using graph theoretical analysis based on diffusion-tensor imaging (DTI). In addition, we investigated differences in the values of diffusion tensors and scalars, fractional anisotropy (FA), and mean diffusivity (MD) of subcortical structures between patients with focal epilepsy and healthy subjects.MethodsOne hundred patients with focal epilepsy and normal magnetic resonance imaging (MRI) findings and 80 age- and sex-matched healthy subjects were recruited prospectively. All subjects underwent DTI to obtain data suitable for graph theoretical analysis. We investigated the differences in the node strength, cluster coefficient, eigenvector centrality, page-rank centrality measures, FA, and MD of subcortical structures between patients with epilepsy and healthy subjects.ResultsAfter performing multiple corrections, the cluster coefficient and the eigenvector centrality of the globus pallidus were higher in patients with epilepsy than in healthy subjects (p=0.006 and p=0.008, respectively). In addition, the strength and the page-rank centrality of the globus pallidus tended to be higher in patients with epilepsy than in healthy subjects (p=0.092 and p=0.032, respectively). The cluster coefficient of the putamen was lower in patients with epilepsy than in healthy subjects (p=0.004). The FA values of the caudate nucleus and thalamus were significantly lower in patients with epilepsy than in healthy subjects (p=0.009 and p=0.007, respectively), whereas the MD value of the thalamus was higher than that in healthy subjects (p=0.005).ConclusionsWe discovered the presence of hub reorganization of subcortical structures in focal epilepsy patients with normal MRI findings, suggesting that subcortical structures play a pivotal role as a hub in the epilepsy network. These findings further reinforce the idea that epilepsy is a network disease.

The medium-term results of acromioclavicular joint arthroscopy with chondral and meniscal debridement.

Surgical management of a young patient with a stable but painful acromioclavicular (AC) joint but normal imagining is a challenging problem. A standard arthroscopic excision of distal clavicle seems too aggressive. An alternative procedure is arthroscopic debridement of the joint, particularly the often torn meniscus, and chondroplasty. This study demonstrates in younger patients the medium-term result of arthroscopic debridement of a painful AC joint. Fifty-three young adult patients with a stable but painful AC joint, and virtually normal magnetic resonance imaging (MRI) scan, had arthroscopic debridement of the AC joint. Follow-up was with questionnaire and American Shoulder and Elbow Surgeons Shoulder Score (ASES). Mean age was 29 years (18-39), 41 male, 31 dominant arm. Twenty-two patients demonstrated additional shoulder pathology. Two patients had a later distal clavicle excision. Five patients had later surgery to other areas of the shoulder but had an asymptomatic AC joint. Thirty-eight patients completed the ASES questionnaire at mean 44 months (24-86) post-operation. The mean ASES score was 82.8 (52-100). There was no association between ASES score and AC joint disease severity found at operation ( p = 0.25). Seven patients had ongoing shoulder symptoms, although none were severe enough to warrant any treatment. In this young group of patients with arthroscopic AC joint debridement, most had good relief of the AC joint related symptoms. This is a worthwhile procedure in the young patient, with quick recovery, and does not preclude further AC joint surgery later.

Collision induced magnetic resonance in Cesium atoms

The radiofrequency-optical double magnetic resonance in cesium atoms filled in a vapor cell is investigated experimentally. One resonant signal involving spin-exchange collisions is observed in the MZ type magnetic resonance spectrum. We solve Liouville equations describing the dynamics of the system and analyze the role of the spin-exchange collisions in the atomic population distributions under resonant conditions. The theoretical calculations agree very well with the experimental results. In contrast with the normal magnetic resonance, the collision induced magnetic resonance exhibits the interesting saturation effect: both the signal amplitude and the signal linewidth are nearly constant when the laser intensity is above a moderate threshold value, which can be useful for precision measurements of the geomagnetic field.

Novel LAMA2 Gene Mutations Associated with Merosin-Deficient Congenital Muscular Dystrophy

Background:Merosin-deficient congenital muscular dystrophy (MDC1A) is a rare autosomal recessive genetic disease occurred due to mutations in the LAMA2 gene. This study investigated the molecular genetics of three Iranian MDC1A patients who manifested hypotonia, muscle weakness at birth, elevated levels of creatine kinase, and normal magnetic resonance imaging before the age of six months.Methods:Peripheral blood samples were collected from three unrelated patients and their families after obtaining informed written consents. Genomic DNA was extracted and sequenced using next-generation sequencing, followed by Sanger confirmation.Results:Sequencing results revealed a known missense mutation, c.8665G>A, and two novel heterozygous sequencing variants affecting splicing, c.397-4_c.478del and c.7452-1G>A, in the LAMA2 gene. Reverse transcriptase-PCR analysis showed that a new intronic variant, c.7452-1G>A, produced aberrant splicing pattern in the patient.Conclusion:This study expands the mutation spectrum of LAMA2 and assists in the diagnosis, genetic counseling, and prenatal diagnosis of the affected families.

Three-Tesla magnetic resonance imaging of the vestibular endolymphatic space: A systematic qualitative description in healthy ears

Background and PurposeA detailed knowledge of the normal Magnetic Resonance (MR) anatomy of the vestibular endolymphatic space (ES) could be useful to understand the linkage between endolymphatic hydrops (EH) and Ménière’s disease (MD). Our aim was to describe the MR anatomy of the vestibular ES as depicted by MR imaging in healthy ears. MethodsThis report describes a single-center retrospective study. Three readers analyzed the healthy ears of 22 consecutive patients who had undergone MRI for unilateral sudden hearing loss. The readers described the vestibular ES based on a delayed post-contrast 3D-FLAIR sequence according to six well-defined planes, three oblique sagittal (lateral, intermediate and medial) planes and three axial (superior, intermediate and inferior) planes. ResultsOn sagittal lateral and intermediate planes, we identified the SSC ampulla combined with the utricle in 22/22 ears. On the sagittal medial plane, the saccule was detectable in 15/22 (68%) ears, having a club shape with the long axis oriented cranio-caudally; in 7/22 (32%) ears, the saccule presented an oval/round shape that appeared more conspicuously on the axial intermediate plane. The ES occupied the half superior portion of the vestibule in 22/22 ears, never contacting the round and oval windows. On the axial plane, in 17/22 cases, the ES showed a Y-shaped arrangement, while in 5/22 ears (23%), the ES presented a more globular shape. ConclusionMR imaging represents a valid tool to explore the in vivo anatomy of the vestibular ES and to highlight its variability in normal ears.

Stereo-electroencephalography-guided radiofrequency thermocoagulation in patients with focal epilepsy: A systematic review and meta-analysis.

Despite the increasing number of studies reporting results of stereo-electroencephalography (SEEG)-guided radiofrequency-thermocoagulation (SEEG-guided RF-TC) in the treatment of patients with drug-resistant focal epilepsy, the exact efficacy of this approach remains unclear. The seizure-freedom rate varies greatly across studies and the factors associated with efficacy have not been formally investigated. All prospective or retrospective studies reporting efficacy and/or safety of SEEG-guided RF-TC in patients with drug-resistant focal epilepsy were included. The primary outcome was the seizure-free rate 1year after the procedure. Secondary outcomes were (1) the responder rate 1year after the procedure and (2) the proportion of patients with permanent neurologic deficit 1year after the procedure. Each outcome was assessed in all patients and in 4 groups of patients defined by the etiology of epilepsy. Each outcome was pooled using inverse variance weighting, logit transformation of proportion, and a random-effects model. No prospective study was identified and a total of 6 retrospective studies, reporting efficacy and safety data of 296 patients, were included. The pooled rate of permanent neurologic deficit was 2.5% (95% confidence interval [CI] 1.2%-5.3%), without heterogeneity across studies. In contrast, both the seizure-free and responder rates varied greatly across studies, and statistical heterogeneity was high. The pooled seizure-free and responder rates were 23% (95% CI 8%-50%) and 58% (95% CI 36%-77%), respectively. Both for the seizure-free and responder rates, the greatest efficacy was observed in patients with periventricular nodular heterotopia and the lowest in patients with normal magnetic resonance imaging (MRI) findings. SEEG-guided RF-TC is a safe procedure with low risk of complications. In contrast, the level of evidence regarding its efficacy remains low. Better identification of factors associated with seizure outcome are needed.

Alterations of the brain network in idiopathic rapid eye movement sleep behavior disorder: structural connectivity analysis.

To evaluate and compare structural connectivity using graph theoretical analysis in patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) and healthy subjects. Ten consecutive patients with iRBD were recruited from a single tertiary hospital. All patients had normal brain magnetic resonance imaging results on visual inspection. They did not have any other neurological disorder. Control subjects were also enrolled. All subjects underwent three-dimensional volumetric T1-weighted imaging. Absolute structural volumes were calculated using FreeSurfer image analysis software. Structural volume and connectivity analyses were performed with Brain Analysis using Graph Theory. Compared to healthy controls, patients with iRBD showed significant alterations in cortical and subcortical volumes, showing increased volumes of frontal cortex, thalamus, and caudate nucleus. In addition, patients with iRBD exhibited significantly different structural connectivity compared to healthy controls. In measures of global network, average degree, global efficiency, and local efficiency were decreased whereas characteristic path length was increased in iRBD patients. In measures of local network, there was significant hub reorganization in patients with iRBD. Betweenness centrality of caudate nucleus and frontal cortex was increased in patients with iRBD. This is the first study to report that structural volume and connectivity in patients with iRBD are significantly different from those in healthy controls. iRBD patients exhibited disrupted topological disorganization of the global brain network and hub reorganization. These alterations are implicated in the pathogenesis of iRBD. They might be potential biomarkers of iRBD.

Normal magnetic resonance anatomy of the hind foot of Egyptian buffalo (Bubalus bubalis): A correlative low‐field T1‐ and T2‐weighted MRI and sectional anatomy atlas

Buffaloes represent a major source of milk production, especially in developing countries including Egypt. The buffalo foot is frequently involved in a large proportion of lameness cases. The relatively small size and complexity of its structures often render the radiographic evaluation of the foot challenging. Magnetic resonance imaging (MRI) is a noninvasive imaging technique that is regarded as both safe and accurate for assessment of the foot disorders in both man and animals. The purpose of the current investigation was to describe the MRI anatomy of buffalo foot using cadaveric hind feet. The feet were subjected to consecutive MRI scanning using a 0.3 Tesla scanner. Both T1-weighted (T1-W) and T2-weighted (T2-W) spin-echo pulse sequences were applied in dorsal, sagittal and transverse planes. The heterogeneity of signal intensities noted amongst foot components allowed for clear differentiation of bones, tendons, ligaments, adipose tissue and synovial fluid. The T1-W images provided an excellent overview of the foot. They were valuable for visualizing the bones and the alignment of tendons and ligaments. The T2-W images were particularly useful for the evaluation of synovial structures such as tendon sheaths and joint cavities. A communication between the two plantar sacs of the metatarsophalangeal (fetlock) joints was evident in T2-W images. MRI findings were further confirmed using relevant gross anatomical sections. The present study establishes a detailed MRI anatomic reference of buffalo foot that could help veterinary researchers, clinicians and surgeons for increasing the accuracy of interpretation of foot MRI scans of both healthy and diseased animals.

Cerebral and Extracerebral Vasoreactivity in Patients With Different Clinical Manifestations of Cerebral Small-Vessel Disease: Data From the Significance of Hemodynamic and Hemostatic Factors in the Course of Different Manifestations of Cerebral Small-Vessel Disease Study.

Endothelial dysfunction has been implicated in the pathogenesis of cerebral small-vessel disease (SVD). Little is known about the relationship between SVD and measures of endothelium-dependent vasodilatation and cerebral vasomotor reactivity. The aim of this study was to evaluate cerebral and extracerebral endothelial dysfunction in patients with different manifestations of SVD and to assess the relationship between endothelial dysfunction and radiologic markers of SVD. The vasomotor reactivity reserve (VMRr), breath-holding index (BHI) of the middle cerebral arteries, and brachial artery flow-mediated dilatation (FMD) were measured with ultrasound techniques in 90 patients (30 in each group) older than 60 years with extensive white matter lesions (Fazekas grade ≥ 2) with a history of lacunar stroke, vascular dementia, or parkinsonism and 30 individuals with normal magnetic resonance imaging findings (control group). All groups were matched for age, sex, hypertension, and diabetes. The mean age ± SD (71.8 ± 3.4 versus 71.7 ± 3.4 years), sex distribution, and prevalence of the main vascular risk factors were similar in the SVD and control groups. The VMRr (56.6% ± 18.3% versus 77.1% ± 16.9%), BHI (0.8 ± 0.3 versus 1.1 ± 0.4), and FMD (5.8% ± 4 versus 12.1% ± 5.2%) were severely impaired in the SVD groups compared to the control group (P < .01). The vascular responses to all tests was similar in the SVD groups, but they were significantly decreased in patients with severe white matter lesions, marked brain atrophy, and enlarged perivascular spaces. This study was the first that simultaneously evaluated cerebral and extracerebral vasodilator responses in a well-phenotyped cohort of patients with lacunar stroke, vascular dementia, or parkinsonism. The VMRr, BHI, and FMD were more severely impaired in patients with SVD, regardless of its clinical manifestation, than in control participants. All measures were significantly lower in patients with severe white-matter lesions, brain atrophy, or enlarged perivascular spaces.

Evolution of Brain Glucose Metabolic Abnormalities in Children With Epilepsy and SCN1A Gene Variants.

Three children with drug-refractory epilepsy, normal magnetic resonance image (MRI), and a heterozygous SCN1A variant underwent 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography (FDG-PET) scanning between age 6 months and 1 year and then at age 3 years 6 months to 5 years 5 months. Regional FDG uptake values were compared to those measured in age- and gender-matched pseudo-controls. At baseline, the brain glucose metabolic pattern in the SCN1A group was similar to that of the pseudo-controls. At follow-up, robust decreases of normalized FDG uptake was found in bilateral frontal, parietal and temporal cortex, with milder decreases in occipital cortex. Children with epilepsy and an SCN1A variant have a normal pattern of cerebral glucose metabolism at around 1 year of age but develop bilateral cortical glucose hypometabolism by age 4 years, with maximal decreases in frontal, parietal, and temporal cortex. This metabolic pattern may be characteristic of epilepsy associated with SCN1A variants and may serve as a biomarker to monitor disease progression and response to treatments.

A Rare Complication of Sarcoidosis

BackgroundCerebral vasculitis is a serious, but uncommon inflammatory condition of the blood vessel walls, with an annual incidence of 1-2 per million. A variety of disorders including encephalopathy, stroke, seizure, acute or subacute focal deficits should be considered as a differential diagnosis. Clinical caseA 56-year old male with a past history of pulmonary sarcoid presented with a unilateral facial numbness and loss of balance arising during sleep. His computed tomography scan of the brain was normal but brain magnetic resonance imaging with gadolinium demonstrated scattered infarcts in mixture of stroke topography not purely in keeping with embolism nor intrinsic small vessel disease. Further investigations including carotid ultrasound, transthoracic echo and 24-hour electrocardiogram were within normal limits. However, computed tomography angiography showed evidence of a widespread intracranial vasculopathy, as well as evidence of dissection of the left common carotid artery. His elevated calcium was consistence with a sarcoidosis relapse and cerebrospinal fluid analysis was in keeping with a central nervous system inflammatory process. Treatment was commenced with high dose steroids with additional pulsed intravenous cyclophosphamide together with antiplatelet therapy and a statin. ConclusionsThis case illustrates the intracranial vasculopathy as a rare complication of sarcoidosis. Although sarcoid is well recognized to affect the central nervous system, it is unusual in the form of cerebral vasculitis.

Diffusion weighted Image MRI in Assessment of Patients with Multiple Myeloma

Background: Recent developments in diagnostic imaging techniques have magnified the role and potential of MRI in patients with multiple myeloma. Quantitative diffusion-weighted imaging of the bone marrow is adjunct tool for the diagnosis of a diffuse MR imaging pattern in patients with multiple myeloma. Aim of the Work: This study aimed to evaluate the apparent diffusion coefficients (ADCs) of magnetic resonance (MR) imaging patterns in the bone marrow of patients with multiple myeloma (MM) and to determine a threshold ADC that may help distinguish a diffuse from a normal pattern with high accuracy Patients and Methods: This study was carried out in Radiology Department of Ain Shams University Hospitals. This study included 30 patients newly diagnosed, untreated MM and 16 healthy control subjects underwent spinal MR imaging including diffusion-weighted imaging, and bone marrow ADCs were calculated. Pattern assignment was based on visual assessment of conventional MR images. Results: Mean ADCs 6 standard deviation in patients with MM for the normal, focal, and diffuse MR imaging patterns were 0.360 x 10-3 mm2/sec +/- 0.110, 1.046 x 10-3 mm2/sec +/- 0.232, and 0.770 x 10-3 mm2/sec +/- 0.135, respectively. There were significant differences in ADCs between diffuse and normal (P .001), diffuse and focal (P.001), and focal and normal (P.001) patterns. Patients with a diffuse pattern had more features of advanced disease, higher international staging system score, increased incidence of high-risk cytogenetics, and higher revised international staging system score. ADCs greater than 0.548 x 10-3 mm2/sec showed 100% sensitivity (9 of 9) and 98% specificity (10 of 11) for the diagnosis of a diffuse (vs normal) MR imaging pattern, whereas an ADC greater than 0.597 x 10-3 mm2/sec showed 100% sensitivity (9 of 9) and 100% specificity. Conclusion: ADCs of MR imaging patterns in patients with MM differ significantly. A diffuse MR imaging pattern can be distinguished more objectively from a normal MR imaging pattern by adding quantitative diffusion-weighted imaging to standard MR imaging protocols.

Diffusion weighted Image MRI in Assessment of Patients with Multiple Myeloma

Background: Recent developments in diagnostic imaging techniques have magnified the role and potential of MRI in patients with multiple myeloma. Quantitative diffusion-weighted imaging of the bone marrow is adjunct tool for the diagnosis of a diffuse MR imaging pattern in patients with multiple myeloma. Aim of the Work: This study aimed to evaluate the apparent diffusion coefficients (ADCs) of magnetic resonance (MR) imaging patterns in the bone marrow of patients with multiple myeloma (MM) and to determine a threshold ADC that may help distinguish a diffuse from a normal pattern with high accuracy Patients and Methods: This study was carried out in Radiology Department of Ain Shams University Hospitals. This study included 30 patients newly diagnosed, untreated MM and 16 healthy control subjects underwent spinal MR imaging including diffusion-weighted imaging, and bone marrow ADCs were calculated. Pattern assignment was based on visual assessment of conventional MR images. Results: Mean ADCs 6 standard deviation in patients with MM for the normal, focal, and diffuse MR imaging patterns were 0.360 x 10-3 mm2/sec +/- 0.110, 1.046 x 10-3 mm2/sec +/- 0.232, and 0.770 x 10-3 mm2/sec +/- 0.135, respectively. There were significant differences in ADCs between diffuse and normal (P .001), diffuse and focal (P.001), and focal and normal (P.001) patterns. Patients with a diffuse pattern had more features of advanced disease, higher international staging system score, increased incidence of high-risk cytogenetics, and higher revised international staging system score. ADCs greater than 0.548 x 10-3 mm2/sec showed 100% sensitivity (9 of 9) and 98% specificity (10 of 11) for the diagnosis of a diffuse (vs normal) MR imaging pattern, whereas an ADC greater than 0.597 x 10-3 mm2/sec showed 100% sensitivity (9 of 9) and 100% specificity. Conclusion: ADCs of MR imaging patterns in patients with MM differ significantly. A diffuse MR imaging pattern can be distinguished more objectively from a normal MR imaging pattern by adding quantitative diffusion-weighted imaging to standard MR imaging protocols.

Stress fracture of distal femur identified with musculoskeletal ultrasound after normal x-ray and magnetic resonance imaging

Magnetic resonance imaging (MRI) and x-ray have traditionally been used to identify musculoskeletal pathology. Diagnostic musculoskeletal ultrasound, however, is becoming increasingly popular among physiatrists. A 35-year-old male runner with no significant past medical history presented with a complaint of right medial knee pain for the past 6 to 8 weeks. He reports that he had recently increased his running mileage significantly while running in shoes that were due to be replaced. He had stopped running but noted that the pain persisted. He described the pain as located in one specific spot on the medial aspect of the right knee, rated 4/10 most of the time, but was exacerbated by putting more force through his leg with activities including jogging, going up and down stairs, or carrying heavy objects. X-rays of the right knee were obtained and were normal, which prompted further imaging with an MRI one week later, which was also normal. Laboratory testing was remarkable for vitamin D deficiency of 13 ng/mL. Musculoskeletal ultrasound revealed a small fracture of the medial epicondyle of the femur measuring 3 mm × 3 mm that was tender to sonopalpation. The patient was instructed to avoid running until pain free for at least 2 weeks before starting on a graduated return to running protocol. Musculoskeletal ultrasound may be a useful imaging modality for identifying stress fractures even in some cases where traditional imaging with x-ray and MRI are negative. This may have important implications for use in resource-limited settings where ultrasound is portable and relatively inexpensive in comparison to MRI.

Síndrome de Cushing Ectópica: Um Desafio Diagnóstico e Terapêutico

INTRODUÇÃO: A síndrome de Cushing ectópica é uma entidade rara e a identificação do tumor produtor de hor-mona adrenocorticotrópica (ACTH) pode ocorrer anos após o diagnóstico da síndrome de Cushing, dificultando a orientação terapêutica destes doentes.CASO CLÍNICO: Mulher de 78 anos referenciada à consulta de Endocrinologia por síndrome de Cushing. Apresenta-va sinais e sintomas de hipercortisolismo e a investigação demonstrou síndrome de Cushing ACTH dependente, com ressonância magnética hipofisária sem alterações, cateterismo dos seios petrosos negativo e nódulo pulmonar de 8 mm. A cintigrafia com recetores da somatostatina, a PET-68Ga-SRP, a broncofibroscopia e a citologia do aspirado brônquico não revelaram alterações. Por franco agravamento clínico, iniciou-se terapêutica com metirapona, com resposta clínica e analítica muito favorável. DISCUSSÃO: Este caso revelou-se um desafio diagnóstico e terapêutico. Embora sem localização do tumor primário, atingiu-se o principal objetivo, o controlo do hipercortisolismo, com melhoria da qualidade de vida da doente.

Utility of additional dedicated high-resolution 3T MRI in children with medically refractory focal epilepsy

PurposeIn patients with medically refractory epilepsy and normal magnetic resonance imaging (MRI), high-resolution dedicated MRI may identify cryptic lesions. The aim of this study was to assess improvement in lesion detection and its impact on clinical management, using additional high-resolution dedicated 3T MRI in children with medically refractory epilepsy who had normal 3T epilepsy protocol MRI. Materials and methodsChildren who had resective epilepsy surgery and suspected focal cortical dysplasia (FCD) or normal 3T epilepsy protocol MRI were included. Those with other diagnosis on MRI including tumor and hippocampal sclerosis were excluded. Patients who had normal MRI on 3T epilepsy protocol underwent dedicated high-resolution 3T MRI through the epileptogenic zone, guided by video EEG, Magnetoencephalography and FDG-PET data. Results101 patients with at least 1 year follow-up were included. Twenty-nine of 44 (66%) patients who had normal epilepsy protocol MRI had a lesion identified on dedicated high-resolution MRI. The addition of dedicated high-resolution MRI to standard epilepsy protocol increased sensitivity from 53.1% (95%CI: 40%–66%) to 85.9% (95%CI: 75%–93%). Identified lesions were concordant to surgical resection in all patients and guided depth/strip electrode insertion in 20/25 (80%) patients who underwent staged resection. Dedicated MRI detected small deep seated lesions in 10/20 (50%), and guided depth electrodes placement, without which it would not be feasible, as the lobar location of epileptogenic zone from other non-invasive tests were not sufficiently precise. ConclusionPatients with non-lesional epilepsy on standard epilepsy protocol MR may benefit from high-resolution dedicated MRI to aid identification of an underlying lesion, which could impact surgical management and improve seizure control.

(37) Pyruvate Dehydrogenase Complex Deficiency with normal Brain MRI: A Case report

Introduction: Pyruvate dehydrogenase complex deficiency (PDCD) is a rare genetic, life-threatening mitochondrial disorder causing lactic acidosis, and progressive neurological and neuromuscular degeneration. Structural abnormalities of the brain are observed in the majority of patients. We describe a patient with PDCD with a normal magnetic resonance Imaging (MRI). Case: A 20-month-old boy with history of hypotonia and developmental delay, presented with respiratory distress and hypoxia. He was diagnosed with bronchiolitis from Metapneumovirus. Two days after being started on PediaSure feeds, he developed respiratory arrest requiring intubation. Despite normal …

Chaotic firefly algorithm-based fuzzy C-means algorithm for segmentation of brain tissues in magnetic resonance images

Image segmentation with clustering approach is widely used in biomedical application. Accurate brain Magnetic Resonance (MR) image segmentation is a challenging task due to the complex anatomical structure of brain tissues in addition to the existence of intensity inhomogeneity, partial volume effects and noise. In this study, a spatial modified bias corrected FCM algorithm is applied to brain MRI for the purpose of segmentation into White Matter (WM), Gray Matter (GM) and Cerebrospinal fluid (CSF) in MR images. So to overcome the uncertainty caused by the above effects, a modified Fuzzy C-Means (m-FCM) algorithm for MR brain image segmentation is presented in this paper. Also FCM suffers from initialization sensitivity, to overcome this we have used chaos theory based firefly algorithm. This paper presents a novel application of FCM clustering by using Firefly algorithm with a chaotic map to initialize the population of fireflies and tune the absorption coefficient (λ), for increasing the global search mobility. This algorithm is called chaotic firefly integrated Fuzzy C-means (C-FAFCM) algorithm, which embeds chaos map in the Firefly Algorithm. The proposed technique is applied to several simulated and real T1-weighted for normal magnetic resonance brain images, taken from IBSR and BrainWeb database. The algorithm is realized by incorporating the spatial neighborhood information into the standard FCM algorithm and modifying the membership weighting of each cluster by regularizing it by Total Variation (TV) denoising. The experimental results on both simulated and real brain MRI datasets demonstrate that our proposed method (C-FAFCM) has satisfactory outputs in comparison with some other state of the art, based on FCM and non FCM based algorithms.

Evoked potentials predict psychomotor development in neonates with normal MRI after hypothermia for hypoxic-ischemic encephalopathy

ObjectivesTo assess the prognostic role of evoked potentials (EP) in neonates with normal magnetic resonance imaging (MRI) after therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE). MethodsThirty-five neonates recruited for TH because of HIE, having normal neonatal MRI, performed neonatal somatosensory (SEP), visual (VEP) evoked potentials and electroencephalogram (EEG). The effect of SEP, VEP or EEG abnormalities on Griffith’s developmental scales at 12 and 24 months was measured; positive (PPV) and negative (NPV) predictive value, sensitivity, specificity and accuracy were calculated. ResultsAt 24 months, 28% had global psychomotor impairment and 57% had isolated impairments. VEP abnormality was associated with impaired hearing-language score (p = 0.002) and performance score (p < 0.0001). VEP achieved best PPV (0.91, 95% C.I. 0.62–0.99) and specificity (0.93, 95% C.I. 0.70–0.99). The combination of neurophysiological tests achieved the best NPV (0.85, 95% C.I. 0.58–0.96), sensitivity (0.90, 95% C.I. 0.70–0.97), overall accuracy (0.83, 95% C.I. 0.67–0.92). ConclusionsPsychomotor sequelae may occur in survivors of neonatal HIE with normal MRI. VEP is the single best neurophysiological prognostic marker but the combination of neurophysiological tests has a better value. SignificanceWhen facing the challenge of neurodevelopmental prognosis in infants with normal MRI after TH, EPs are useful prognostic tools, complementary to EEG.

Arterial Wall Imaging in Pediatric Stroke.

Arteriopathy is common in childhood arterial ischemic stroke (AIS) and predicts stroke recurrence. Currently available vascular imaging techniques mainly image the arterial lumen rather than the vessel wall and have a limited ability to differentiate among common arteriopathies. We aimed to investigate the value of a magnetic resonance imaging-based technique, namely noninvasive arterial wall imaging (AWI), for distinguishing among arteriopathy subtypes in a consecutive cohort of children presenting with AIS. Children with confirmed AIS and magnetic resonance angiography underwent 3-Tesla AWI including T1-weighted 2-dimensional fluid-attenuated inversion recovery fast spin echo sequences pre- and post-gadolinium contrast. AWI characteristics, including wall enhancement, wall thickening, and luminal stenosis, were documented for all. Twenty-six children with AIS had AWI. Of these, 9 (35%) had AWI enhancement. AWI enhancement was associated with anterior circulation magnetic resonance angiography abnormality and cortical infarction in 8 of 9 (89%) children and normal magnetic resonance angiography with posterior circulation subcortical infarction in 1 (1 of 9; 11%) child. AWI enhancement was not seen in 17 (65%), 10 (59%) of whom had an abnormal magnetic resonance angiography. Distinct patterns of pre- and postcontrast signal abnormality were demonstrated in the vessel wall in the region of interest in children with transient cerebral arteriopathy, arterial dissection, primary central nervous system angiitis, dissecting aneurysm, and cardioembolic stroke. AWI is a noninvasive, high-resolution magnetic resonance AWI technique, which can be successfully used in children presenting with AIS. Patterns of AWI enhancement are recognizable and associated with specific AIS pathogeneses. Further studies are required to assess the additional diagnostic utility of AWI over routine vascular imaging techniques, in childhood AIS.