Ex vivo porcine model for eye, eyelid, and orbit movement analysis of 4-mm ferromagnetic foreign bodies in MRI.

PURPOSE: Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to movement, especially in and around the eyes. Ferromagnetic foreign bodies located in the intraocular area, eyelids, and orbit are thus prohibited from undergoing MRI. The aim of the study was to analyze movement of 4-mm ferromagnetic foreign bodies in MRI in the eye, eyelid, and orbit using computed tomography (CT) scan. METHOD: We developed a porcine model using 12 quarters of fresh porcine heads. Each porcine head included one whole orbit with the ocular globe, orbital fat, muscles, and eyelids. Four-millimeter FFB were implanted in the eye within 2 days post-slaughter, and images were acquired within 5 days post-slaughter. Four-millimeter FFB movement was analyzed after 1.5-Tesla (T) MRI. Four locations were tested: intravitreous, suprachoroidal, intraorbital fat, and intrapalpebral. Movement analysis was assessed using computed tomography (CT) scan. RESULTS: The intravitreous ferromagnetic ball moved 14.0 ± 8.8 mm (p < 0.01), the suprachoroidal ball moved 16.8 ± 5.4 mm (p < 0.01), the intraorbital fat ball moved 5.8 ± 0.9 mm (p > 0.05), and the intrapalpebral ball moved 2.0 ± 0.4 mm (p > 0.05). CONCLUSION: The ex vivo porcine model was able to study FFB movement. The 4-mm ferromagnetic balls moved in intravitreous and in suprachoroidal locations after MRI.

Primary total hip arthroplasty with a fully porous-coated uncemented stem: up to twenty-eight years. Retrospective cohort study.

PURPOSE: The use of cementless prosthesis has increased in the last 30 years with the aim of improving the long-term results of total hip arthroplasties in young and active patients. Encouraging results have recently been reported for cementless titanium and cobalt chromium stems. However, there are few studies with long-term follow-up, and the majority have analysed several models of uncemented stems due to their modifications over the years. Therefore, the aim was to assess the long-term survival rate of the Mittelmeier Mark III or Autophor 900-S stem. METHODS: A retrospective cohort study of both gender patients under 70 years old with at least one implanted Mittelmeier Mark III uncemented stem was performed. Survival rate was defined as the proportion of stems that did not need a surgical revision from any cause. Clinical status was evaluated using the Merle d'Aubigne scale modified by Matta (excellent/good/fair/poor). RESULTS: Between 1990 and 1999, 73 stems were implanted. The mean (SD) age at surgical time was 49.3 (9.9) years, and the median (range) of follow-up was 22 (1-28) years. The overall survival rate was 93% (68/73, 95%CI: 85-97%). The stem revisions were due to stem breakage (n = 2), to aseptic loosening (n = 2) and to septic loosening (n = 1). Clinical results were: excellent 84%, good 15% and fair 1.5%. CONCLUSIONS: The Mittelmeier Mark III stem had an excellent survival rate with a stable long-term fixation and excellent clinical outcomes.

Multicenter initial experience with the EmboTrap device in acute anterior ischemic stroke.

BACKGROUND AND PURPOSE: Mechanical thrombectomy predominantly using stent retrievers effectively restores cerebral blood flow and improves functional outcomes in patients with acute ischemic stroke. We sought to determine the safety and efficacy of mechanical thrombectomy using the EmboTrap device. MATERIALS AND METHODS: We identified 80 consecutive patients from 4 centers with acute ischemic stroke treated with EmboTrap from June 2015 to December 2016. All patients had confirmed large vessel occlusions in the anterior circulation using CT or MR angiography with salvageable tissue. We assessed baseline characteristics and treatment related parameters including onset-to-treatment time, recanalization success (mTICI 2b or greater), complications, and good clinical outcome (mRS 0 to 2). RESULTS: Successful recanalization was achieved in 72 patients (90%). When considering the use of a second thrombectomy device as failure, the EmboTrap successfully recanalized 65 patients (81%), with complete (mTICI 3) recanalization in 40 patients (50%) within 1 or 2 passes. Median procedure time (groin to recanalization) was 35 minutes (8-161 minutes). During the procedure, distal emboli in previously unaffected territories were found in 5 (6%) patients. There were 3 vasospasms (4%) and no vessel perforations. Intracranial hemorrhage on CT at day 1 was found in 18 17 (2321%) patients, none with subarachnoid hemorrhages, and 5 were symptomatic (6%). Good clinical outcome occurred in 4749/68 78 patients (6963%). CONCLUSIONS: In this multicenter retrospective study, the EmboTrap device achieved high recanalization rates, good clinical outcomes and was safe in treating acute stroke patients with large vessel occlusions.

The learning curve effect on embolization of cerebral dural arteriovenous fistula single-center experience in 48 consecutive patients.

BACKGROUND: Cerebral dural arteriovenous fistulas (DAVFs) are rare intracranial vascular lesions but can cause significant morbidity and mortality. OBJECTIVES: To analyze the effect of the center's experience on DAVF embolization efficacy and safety. METHODS: From May 2008 to October 2014, 57 embolization procedures were attempted on 48 patients (37 men and 11 women; median age: 63.9 years) for DAVF in a single center. DAVF presented with cortical venous reflux in 44/48 cases (91.7%) and hemorrhagic manifestation in 21/48 cases (43.75%). Angiographic occlusion quality, whether complete or incomplete (efficacy), and neurological complications (safety) were recorded. The patient population was divided into four consecutive quartiles during the inclusion period to assess the progress profile. Efficacy and safety outcomes were compared with Fisher's test. RESULTS: A logistic regression was performed to explore a learning curve phenomenon, showing a significant association between the chronological rank in the cohort and embolization efficacy (P=0.007). Significant differences were found between first and last quarter (P=0.036). The endovascular technique involved an arterial injection of Onyx® in 36/48 cases (75%), administered via the middle meningeal artery in 25/36 cases (69.5%). The complete occlusion rate improved significantly from 33.3% for the first quartile of the population, to 75.0% for the 2nd and 3rd quartiles and 83.3% for the last quartile. Neurological complications were found in 7/48 patients (14.6%), the rate decreased by 41.7% to 16.7%, without statistically difference. CONCLUSION: The efficacy and safety of DAVF embolization improved with the experience gained at the center, suggesting the existence of a learning curve.

Chikungunya outbreak in Montpellier, France, September to October 2014.

In October 2014, an outbreak of 12 autochthonous chikungunya cases, 11 confirmed and 1 probable, was detected in a district of Montpellier, a town in the south of France colonised by the vector Aedes albopictus since 2010. A case returning from Cameroon living in the affected district was identified as the primary case. The epidemiological investigations and the repeated vector control treatments performed in the area and around places frequented by cases helped to contain the outbreak. In 2014, the chikungunya and dengue surveillance system in mainland France was challenged by numerous imported cases due to the chikungunya epidemic ongoing in the Caribbean Islands. This first significant outbreak of chikungunya in Europe since the 2007 Italian epidemic, however, was due to an East Central South African (ECSA) strain, imported by a traveller returning from West Africa. Important lessons were learned from this episode, which reminds us that the threat of a chikungunya epidemic in southern Europe is real.

Pinning-dependent field-driven domain wall dynamics and thermal scaling in an ultrathin Pt/Co/Pt magnetic film.

Magnetic-field-driven domain wall motion in an ultrathin Pt/Co(0.45 nm)/Pt ferromagnetic film with perpendicular anisotropy is studied over a wide temperature range. Three different pinning dependent dynamical regimes are clearly identified: the creep, the thermally assisted flux flow, and the depinning, as well as their corresponding crossovers. The wall elastic energy and microscopic parameters characterizing the pinning are determined. Both the extracted thermal rounding exponent at the depinning transition, ψ=0.15, and the Larkin length crossover exponent, ϕ=0.24, fit well with the numerical predictions.

Multidisciplinary management of posterior fossa dural arteriovenous fistula: A single-center experience.

PURPOSE: The management of posterior fossa dural arteriovenous fistulas (pfDAVFs) is challenging. Here, we show how multidisciplinarity leads to their successful management, even in complex cases. METHODS: All pfDAVFs managed from 2010 to 2019 at our center were reviewed. The preoperative clinical and radiological characteristics, their management and the occlusion rate were retrieved. The radiological and functional outcomes were retrieved at discharge and last follow-up (FU). RESULTS: n=27 patients were included (6 females, mean age: 61-years-old, mean FU: 22.5 months). n=8 patients presented with cerebral hemorrhage. Among patients with ruptured pfDAVFs, n=7 had headache, n=4 had ataxia, and n=2 had impaired level of consciousness. In the unruptured group N (n=19), n=7 patients had headache, n=6 patients had focal neurological deficit, n=4 patients had tinnitus, n=3 (had ataxia, and one presented with seizure. n=24 patients were treated by endovascular therapy (EVT), n=2 patients were treated by microsurgery (MS) and n=1 patient was managed with a combined approach. Re-treatment was necessary in n=6 patients. n=24 patients showed total exclusion at last FU. n=2 patients died during the first 30 days; n=1 patient died during FU. CONCLUSIONS: While EVT should be advocated as the first line therapy whenever possible, MS should not be banned from the treatment armamentarium. Neurosurgeons must be able to achieve direct surgical occlusion when the angioarchitecture speaks against EVT.

Apathy in depression: An arterial spin labeling perfusion MRI study.

INTRODUCTION: Apathy, as defined as a deficit in goal-directed behaviors, is a critical clinical dimension in depression associated with chronic impairment. Little is known about its cerebral perfusion specificities in depression. To explore neurovascular mechanisms underpinning apathy in depression by pseudo-continuous arterial spin labeling (pCASL) magnetic resonance imaging (MRI). METHODS: Perfusion imaging analysis was performed on 90 depressed patients included in a prospective study between November 2014 and February 2017. Imaging data included anatomical 3D T1-weighted and perfusion pCASL sequences. A multiple regression analysis relating the quantified cerebral blood flow (CBF) in different regions of interest defined from the FreeSurfer atlas, to the Apathy Evaluation Scale (AES) total score was conducted. RESULTS: After confound adjustment (demographics, disease and clinical characteristics) and correction for multiple comparisons, we observed a strong negative relationship between the CBF in the left anterior cingulate cortex (ACC) and the AES score (standardized beta = -0.74, corrected p value = 0.0008). CONCLUSION: Our results emphasized the left ACC as a key region involved in apathy severity in a population of depressed participants. Perfusion correlates of apathy in depression evidenced in this study may contribute to characterize different phenotypes of depression.

Functional interactions between members of the REPAT family of insect pathogen-induced proteins.

Studies on the transcriptional response to pathogens in the insect larval gut have shown the regulation of several genes after the infection. Repat (REsponse to PAThogens) genes were first identified in Spodoptera exigua midgut as being up-regulated in response to the exposure to Bacillus thuringiensis toxins and baculovirus. Recently, new members of the REPAT family showed a constitutive up-regulation in a B. thuringiensis-resistant population. Based on a yeast two-hybrid screening, we have detected the interaction of REPAT1 with other members of the REPAT family, leading to the discovery of a new member: REPAT8. The functional role of this interaction was shown by following the changes of the subcellular localization of REPAT1 in the presence of REPAT8. REPAT1 alone was localized exclusively in the cytoplasm, while the presence of REPAT8 led to the migration of REPAT1 to the nucleus. Finally, analysis of the expression pattern of eight REPAT members has shown that B. thuringiensis-related treatments (Cry1Ca toxin, Xentari™ product and an acrystalliferous strain) induced a general up-regulation of repat genes, especially of repat2. In contrast, no significant effect was detected after treatment with Escherichia coli or Enterococcus sp., or by the presence of microbiota in the midgut. The results suggest that the different repat genes play different roles in response to pathogens.

Objective chemical fingerprinting of oil spills by partial least-squares discriminant analysis.

An objective method based on partial least-squares discriminant analysis (PLS-DA) was used to assign an oil lump collected on the coastline to a suspected source. The approach is an add-on to current US and European oil fingerprinting standard procedures that are based on lengthy and rather subjective visual comparison of chromatograms. The procedure required an initial variable selection step using the selectivity ratio index (SRI) followed by a PLS-DA model. From the model, a "matching decision diagram" was established that yielded the four possible decisions that may arise from standard procedures (i.e., match, non-match, probable match, and inconclusive). The decision diagram included two limits, one derived from the Q-residuals of the samples of the target class and the other derived from the predicted y of the PLS model. The method was used classify 45 oil lumps collected on the Galician coast after the Prestige wreckage. The results compared satisfactorily with those from the standard methods.

Multimodal MRI cerebral correlates of verbal fluency switching and its impairment in women with depression.

BACKGROUND: The search of biomarkers in the field of depression requires easy implementable tests that are biologically rooted. Qualitative analysis of verbal fluency tests (VFT) are good candidates, but its cerebral correlates are unknown. METHODS: We collected qualitative semantic and phonemic VFT scores along with grey and white matter anatomical MRI of depressed (n = 26) and healthy controls (HC, n = 25) women. Qualitative VFT variables are the "clustering score" (i.e. the ability to produce words within subcategories) and the "switching score" (i.e. the ability to switch between clusters). The clustering and switching scores were automatically calculated using a data-driven approach. Brain measures were cortical thickness (CT) and fractional anisotropy (FA). We tested for associations between CT, FA and qualitative VFT variables within each group. RESULTS: Patients had reduced switching VFT scores compared to HC. Thicker cortex was associated with better switching score in semantic VFT bilaterally in the frontal (superior, rostral middle and inferior gyri), parietal (inferior parietal lobule including the supramarginal gyri), temporal (transverse and fusiform gyri) and occipital (lingual gyri) lobes in the depressed group. Positive association between FA and the switching score in semantic VFT was retrieved in depressed patients within the corpus callosum, right inferior fronto-occipital fasciculus, right superior longitudinal fasciculus extending to the anterior thalamic radiation (all p < 0.05, corrected). CONCLUSION: Together, these results suggest that automatic qualitative VFT scores are associated with brain anatomy and reinforce its potential use as a surrogate for depression cerebral bases.

Assessment of 4D MR Angiography at 3T Compared with DSA for the Follow-up of Embolized Brain Dural Arteriovenous Fistula: A Dual-Center Study.

BACKGROUND AND PURPOSE: 4D contrast-enhanced MRA in the follow-up of treated dural arteriovenous fistulas has rarely been evaluated. Our aim was to evaluate its diagnostic performance at 3T in the follow-up of embolized dural arteriovenous fistulas using DSA as the standard of reference. MATERIALS AND METHODS: Patients treated for dural arteriovenous fistulas in 2 centers between 2008 and 2019 were included if they met the following criteria: 1) dural arteriovenous fistula embolization, and 2) follow-up imaging with <6 months between DSA and 4D contrast-enhanced MRA. Two readers reviewed the 4D contrast-enhanced MRA images, first independently, then in consensus to detect any residual/recurrent dural arteriovenous fistula and to grade cases according to the Cognard classification system. Interobserver and intermodality agreement for the detection of a residual dural arteriovenous fistula and stratification of bleeding risk (0-I-IIa; IIb-IIa+b-III-IV-V) was calculated using κ coefficients. RESULTS: A total of 51 pairs of examinations for 44 patients (median age, 65 years; range, 25-81 years) were analyzed. Interobserver agreement for the detection and stratification of bleeding risk was, respectively, κ = 0.8 (95% CI, 0.6-1) and κ = 0.8 (95% CI, 0.5-1). After consensus review, the sensitivity and specificity of 4D contrast-enhanced MRA for the detection of residual/recurrent dural arteriovenous fistula was 63.6% (95% CI, 40.7%-82.8%) and 96.6% (95% CI, 82.2%-99.9%), respectively. The positive and negative predictive values of 4D contrast-enhanced MRA were 93.3% (95% CI, 68.1%-99.8%) and 77.8% (95% CI, 60.8%-89.9%). Intermodality agreement for the detection and stratification of bleeding risk was good, with κ = 0.60 (95% CI, 0.3-0.8). CONCLUSIONS: 4D contrast-enhanced MRA at 3T is of interest in the follow-up of treated dural arteriovenous fistulas but lacks the sensitivity to replace arteriography.

Dynamic binding of driven interfaces in coupled ultrathin ferromagnetic layers.

We demonstrate experimentally dynamic interface binding in a system consisting of two coupled ferromagnetic layers. While domain walls in each layer have different velocity-field responses, for two broad ranges of the driving field H, walls in the two layers are bound and move at a common velocity. The bound states have their own velocity-field response and arise when the isolated wall velocities in each layer are close, a condition which always occurs as H→0. Several features of the bound states are reproduced using a one-dimensional model, illustrating their general nature.

Magnetization reversal in Pt/Co(0.5 nm)/Pt nano-platelets patterned by focused ion beam lithography.

Arrays of ultrathin Pt/Co(0.5 nm)/Pt nano-platelets with lateral sizes ranging from 30 nm to 1 µm have been patterned by focused ion beam (FIB) lithography under a weak Ga(+) ion fluence. From polar magneto-optical Kerr microscopy it is demonstrated that nano-platelets are ferromagnetic with perpendicular anisotropy down to a size of 50 nm. The irradiation process creates a magnetically soft ring at the nano-platelet periphery in which domain nucleation is initiated at a low field. The magnetization reversal in nano-platelets can be interpreted using a confined droplet model. All of the results prove that ultimate FIB patterning is suitable for preparing discrete magnetic recording media or small magnetic memory elements and nano-devices.

Anatomic variants of the anterior part of the cerebral arterial circle at multidetector computed tomography angiography.

Imaging of the cerebral arterial circle (CAC) is essential in neurovascular diseases such as ischemic stroke for detecting arterial occlusions and evaluating arterial supply, and in subarachnoid or intralobar hemorrhage for detecting intracranial malformations. Multidetector computed tomography angiography (MD-CTA) is increasingly being used for the detection and treatment planning of intracranial aneurysm. For optimal interpretation and treatment planning, this method requires suitable post-processing equipment, and extensive knowledge of the relevant anatomy and anatomical variants. Anatomical variants of the CAC are common, particularly in the anterior CAC, the most common site of intracranial aneurysm. The aim of this review is to illustrate the normal anatomy and most common anatomical variants of the anterior CAC detected by MD-CTA, and to discuss the relevant embryological and technical considerations.

Optimized time-resolved 3D contrast-enhanced MRA at 3T: appreciating the feasibility of assessing cervical paragangliomas.

OBJECTIVES: To describe an optimized 3D time-resolved contrast-enhanced MR angiography (3D TR-CE-MRA) at 3T in diagnosing head and neck paragangliomas and assessing their morphology and relation to neighboring vessels. METHODS: In a prospective study, eight consecutive patients presenting cranial cervical masses suspected to be 10 paragangliomas were examined with 3D TR-CE-MRA at 3T. Two neuroradiologists evaluated the overall image quality, the presence of a paraganglioma, the maximum diameter, as well as the vessel invasion. RESULTS: In all of the cases, the overall image quality was scored as good. The tumors (n=10) were all visualized and localized. The mean maximum diameter was 32.7mm [range 7-80]. Vessel invasion was assessed as uncertain in one case and improbable in nine cases. CONCLUSION: 3D TR-CE-MRA at 3T associated with conventional sequences facilitates a comprehensive investigation of paragangliomas, thus providing the anatomical and functional information.

DWI-Based Algorithm to Predict Disability in Patients Treated with Thrombectomy for Acute Stroke.

BACKGROUND AND PURPOSE: The reasons for poor clinical outcome after thrombectomy for acute stroke, concerning around half of all patients, are misunderstood. We developed a hierarchic algorithm based on DWI to better identify patients at high risk of disability. MATERIALS AND METHODS: Our single-center, retrospective study included consecutive patients with acute ischemic stroke who underwent thrombectomy for large anterior artery occlusion and underwent pretreatment DWI. The primary outcome was the mRS at 3 months after stroke onset. Multivariable regression was used to identify independent clinical and imaging predictors of poor prognosis (mRS > 2) at 3 months, and a hierarchic algorithm predictive of disability was developed. RESULTS: A total of 149 patients were analyzed. In decreasing importance, DWI lesion volume of >80 mL, baseline NIHSS score of >14, age older than 75 years, and time from stroke onset to groin puncture of >4 hours were independent predictors of poor prognosis. The predictive hierarchic algorithm developed from the multivariate analysis predicted the risk of disability at 3 months for up to 100% of patients with a high predictive value. The area under the receiver operating characteristic curve was 0.87. CONCLUSIONS: The DWI-based hierarchic algorithm we developed is highly predictive of disability at 3 months after thrombectomy and is easy to use in routine practice.

Genomic structure and promoter analysis of pathogen-induced repat genes from Spodoptera exigua.

The repat gene family encodes midgut proteins overexpressed in response to pathogen infection in the lepidopteran Spodoptera exigua. Up-regulation of repat genes has been observed after challenging the larvae with both Bacillus thuringiensis toxins and after infection with the baculovirus Autographa californica multiple nucleopolyhedrovirus. In our study, PCR amplification of the genomic region and genome walking were used to obtain the genomic structure and the sequence of the 5'-upstream region of repat1 and repat2, two of the most phylogenetically distant members of the repat family. A similar gene structure between repat1 and repat2 has been found, with conserved exon-intron positions and junction sequences, suggesting a common origin for these genes. Recombinant baculoviruses carrying the firefly luciferase gene under the control of different 5'-upstream regions of the repat1 gene were constructed to elucidate the influence of these regions in gene expression. Infection of Helicoverpa zea gut-derived cells with the recombinant baculoviruses revealed the upstream regions of the repat1 gene which are involved in gene transcription and demonstrated the role of an intron located in the 5'-untranslated region in the enhancement of gene expression.