Arterial Spin Labeling: Techniques, Clinical Applications, and Interpretation.

Arterial spin labeling (ASL) is an emerging noninvasive MRI technique for assessing cerebral perfusion. An important advantage of ASL perfusion is the lack of a requirement for an exogenous tracer. ASL uses magnetically labeled water protons from arterial blood as an endogenous diffusible tracer. For this reason, ASL is an attractive perfusion imaging modality for children and for patients with contraindications or adverse reactions to gadolinium, patients with renal failure, and those who need repeated follow-up imaging. Another advantage of ASL is the possibility of quantifying cerebral blood flow, which provides an opportunity for comparative analysis among multiple longitudinal studies, unlike other MR perfusion techniques, which are semiquantitative and yield relative perfusion parameters. Advances in MRI technology and pulse sequence design have translated ASL beyond the research arena to successful clinical implementation. However, ASL is still underused in routine clinical practice. Some disadvantages of ASL include a lower signal-to-noise ratio and a longer acquisition time than those with dynamic susceptibility contrast-enhanced MRI. Additional factors limiting the use of ASL include variations in existing techniques and pulse sequence design, the complexity of implementation and postprocessing, insufficient experience with and/or knowledge of the potential clinical applications, and the absence of interpretation guidelines. The authors review the technical and physiologic basis of ASL perfusion, as well as artifacts, pitfalls, and its current clinical applications. A practical approach for interpreting ASL findings is also suggested.

"Bunch of acai berries sign": a new radiological sign in patients with CNS involvement in Chagas disease.

Chagas disease is an infection caused by Trypanosoma cruzi, a parasite endemic in Latin America. Acute involvement of the CNS by Chagas has been considered rare, but presumed reactivation of chronic disease in immunosuppressed patients has been the subject of recent reports. Our objective is to describe the clinical and imaging characteristics of four patients with Chagas disease and CNS involvement, and the patients had to have available MRI and a diagnosis confirmed by biopsy. The imaging findings were similar, highlighting the presence of focal cerebral lesions with hypointensity on T2-WI, and these lesions assume a "bunch of acai berries appearance", a fruit involved in the transmission of T. cruzi. The post Gd T1-WI shows punctate enhancement. Knowledge of this pattern may be crucial to recognize this disease in immunocompromised patients from endemic areas.

Metabolomics Integration in Assisted Reproductive Technologies for Enhanced Embryo Selection beyond Morphokinetic Analysis.

Embryo quality evaluation during in vitro development is a crucial factor for the success of assisted reproductive technologies (ARTs). However, the subjectivity inherent in the morphological evaluation by embryologists can introduce inconsistencies that impact the optimal embryo choice for transfer. To provide a more comprehensive evaluation of embryo quality, we undertook the integration of embryo metabolomics alongside standardized morphokinetic classification. The culture medium of 55 embryos (derived from 21 couples undergoing ICSI) was collected at two timepoints (days 3 and 5). Samples were split into Good (n = 29), Lagging (n = 19), and Bad (n = 10) according to embryo morphokinetic evaluation. Embryo metabolic performance was assessed by monitoring the variation in specific metabolites (pyruvate, lactate, alanine, glutamine, acetate, formate) using 1H-NMR. Adjusted metabolite differentials were observed during the first 3 days of culture and found to be discriminative of embryo quality at the end of day 5. Pyruvate, alanine, glutamine, and acetate were major contributors to this discrimination. Good and Lagging embryos were found to export and accumulate pyruvate and glutamine in the first 3 days of culture, while Bad embryos consumed them. This suggests that Bad embryos have less active metabolic activity than Good and Lagging embryos, and these two metabolites are putative biomarkers for embryo quality. This study provides a more comprehensive evaluation of embryo quality and can lead to improvements in ARTs by enabling the selection of the best embryos. By combining morphological assessment and metabolomics, the selection of high-quality embryos with the potential to result in successful pregnancies may become more accurate and consistent.

BlockProof: A Framework for Verifying Authenticity and Integrity of Web Content.

In the Literature, we can find several research works to help in the digital crime fight in order to prove integrity and authenticity of a published document, image or video. Among all the crimes, fake news certainly is among the most recurrent ones and needs to be mitigated. There are several Blockchain-based applications in order to make use of the benefits derived from technology, but little is found to verify the authenticity of Web content records as well as the history of all updates that have taken place in each Web content. Such kind of solution has become important nowadays as a way to cover the gap in the combat against fake news, for example. The purpose of this paper is to present BlockProof, a framework for verifying web content authenticity and integrity that offers a solution for content providers to register Web content, regardless of whether the page has dynamic or static content, in addition to enabling the consultation of the history of all records made for a given URL. We understand that such kind of solution may be useful to data producers/providers to provide evidence that they are in compliance with the fight against fake news, for instance.

Corticospinal tract involvement in spinocerebellar ataxia type 3: a diffusion tensor imaging study.

PURPOSE: The aim of this study was to evaluate the integrity of the corticospinal tracts (CST) in patients with SCA3 and age- and gender-matched healthy control subjects using diffusion tensor imaging (DTI). We also looked at the clinical correlates of such diffusivity abnormalities. METHODS: We assessed 2 cohorts from different Brazilian centers: cohort 1 (n = 29) scanned in a 1.5 T magnet and cohort 2 (n = 91) scanned in a 3.0 T magnet. We used Pearson's coefficients to assess the correlation of CST DTI parameters and ataxia severity (expressed by SARA scores). RESULTS: Two different results were obtained. Cohort 1 showed no significant between-group differences in DTI parameters. Cohort 2 showed significant between-group differences in the FA values in the bilateral precentral gyri (p < 0.001), bilateral superior corona radiata (p < 0.001), bilateral posterior limb of the internal capsule (p < 0.001), bilateral cerebral peduncle (p < 0.001), and bilateral basis pontis (p < 0.001). There was moderate correlation between CST diffusivity parameters and SARA scores in cohort 2 (Pearson correlation coefficient: 0.40-0.59). CONCLUSION: DTI particularly at 3 T is able to uncover and quantify CST damage in SCA3. Moreover, CST microstructural damage may contribute with ataxia severity in the disease.

Sperm selection strategies and their impact on assisted reproductive technology outcomes.

The application of assisted reproductive technologies (ART) has revolutionised the treatment of human infertility, giving hope to the patients previously considered incapable of establishing pregnancy. While semen analysis is performed to access whether a sample has an adequate number of viable, motile and morphologically normal sperm cells able to achieve fertilisation, sperm selection techniques for ART aim to isolate the most competent spermatozoon which is characterised by the highest fertilising potential. Based on the semen analysis results, the correct sperm selection technique must be chosen and applied. In this review, different sperm selection strategies for retrieving spermatozoa with the highest fertilising potential and their impact on ART outcomes are discussed. In addition, advantages and disadvantages of each method and the best suited techniques for each clinical scenario are described.

Predicting Popularity of Video Streaming Services with Representation Learning: A Survey and a Real-World Case Study.

The Internet's popularization has increased the amount of content produced and consumed on the web. To take advantage of this new market, major content producers such as Netflix and Amazon Prime have emerged, focusing on video streaming services. However, despite the large number and diversity of videos made available by these content providers, few of them attract the attention of most users. For example, in the data explored in this article, only 6% of the most popular videos account for 85% of total views. Finding out in advance which videos will be popular is not trivial, especially given many influencing variables. Nevertheless, a tool with this ability would be of great value to help dimension network infrastructure and properly recommend new content to users. In this way, this manuscript examines the machine learning-based approaches that have been proposed to solve the prediction of web content popularity. To this end, we first survey the literature and elaborate a taxonomy that classifies models according to predictive features and describes state-of-the-art features and techniques used to solve this task. While analyzing previous works, we saw an opportunity to use textual features for video prediction. Thus, additionally, we propose a case study that combines features acquired through attribute engineering and word embedding to predict the popularity of a video. The first approach is based on predictive attributes defined by resource engineering. The second takes advantage of word embeddings from video descriptions and titles. We experimented with the proposed techniques in a set of videos from GloboPlay, the largest provider of video streaming services in Latin America. A combination of engineering features and embeddings using the Random Forest algorithm achieved the best result, with an accuracy of 87%.

Mobile vs. Non-Mobile Live-Streaming: A Comparative Analysis of Users Engagement and Interruption Using Big Data from a Large CDN Perspective.

Video streaming on the Internet is constantly changing and growing. New devices and new video delivery mechanisms generate huge gaps in the understanding of how video application works. From exploratory research of one among the largest streaming services in Brazil, this work presents a comparison between mobile and non-mobile users, in large-scale lives. This work focuses on metrics such as engagement, interruption, churn, and payload. This work also presents a report-overview of mobile-users, considering the operating system, geolocation, network access, interruption, and engagement. These results might offer potential information for streaming improvement, in addition to serving as a historical mark.

Case 278: Mutation in ROBO3 Gene-Horizontal Gaze Palsy and Progressive Scoliosis.

HistoryA 13-year-old girl was born to consanguineous parents. She presented with mild intellectual impairment, convergent strabismus, horizontal gaze palsy, and bilateral abducens palsy. Vertical gaze was preserved, and no abnormalities suggesting facial paralysis were noted. In addition, she reported progressive back pain since she was 5 years old. Other symptoms were denied. No medications or related drugs had been administered thus far. The patient underwent brain MRI for further evaluation. Current and previous spine radiographs were also reviewed.

Case 278.

HistoryA 13-year-old girl was born to consanguineous parents. She presented with mild intellectual impairment, convergent strabismus, horizontal gaze palsy, and bilateral abducens palsy. Vertical gaze was preserved, and no abnormalities suggesting facial paralysis were noted. In addition, she reported progressive back pain since she was 5 years old. Other symptoms were denied. No medications or related drugs had been administered thus far.

Severe brain involvement in 5q spinal muscular atrophy type 0.

Spinal muscular atrophy (SMA) type 0 is the most severe form of SMA, associated with the SMN1 gene and manifesting at birth. Most patients die in the first weeks of life. In this work, we present 3 patients with SMA type 0 who survived >1 year and presented diffuse and progressive brain abnormalities on magnetic resonance imaging, which are not usually seen in patients with SMA. Thus, severe brain involvement may likely be the full end manifestation of an already extreme SMA phenotype caused by substantial reduction of the SMN protein in the brain. ANN NEUROL 2019;86:458-462.

Pediatric multiple sclerosis: from clinical basis to imaging spectrum and differential diagnosis.

Pediatric multiple sclerosis (MS) deserves special attention because of its impact on cognitive function and development. Although knowledge regarding pediatric MS has rapidly increased, understanding the peculiarities of this population remains crucial for disease management. There is limited expertise about the efficacy and safety of current disease-modifying agents. Although pathophysiology is not entirely understood, some risk factors and immunological features have been described and are discussed herein. While the revised International Pediatric MS Study Group diagnostic criteria have improved the accuracy of diagnosis, the recently revised McDonald criteria also offer some new insights into the pediatric population. It is fundamental that radiologists have strong knowledge about the vast spectrum of demyelinating disorders that can occur in childhood to ensure appropriate diagnosis and provide early treatment.

Tips and tricks in the diagnosis of intracranial dural arteriovenous fistulas: A pictorial review.

Dural arteriovenous fistulas (DAVFs) are complex vascular abnormalities that account for 10-15% of intracranial vascular malformations. DAVFs are typically encountered in middle-aged adults, with a slightly female predominance. The causative factors are still uncertain; however, abnormal local hemodynamics and neoangiogenesis related to dural sinus or venous thrombosis can contribute to DAVF occurrence. The diagnosis is dependent on a high level of clinical suspicion and high-resolution imaging techniques. Computed tomography and/or magnetic resonance imaging aid in the diagnosis, but conventional angiography remains the most accurate method for the complete characterization and classification of DAVFs. The therapeutic approach can be conservative or more aggressive, based on symptom severity, sequelae risk and patient characteristics. This article is a pictorial review of adult intracranial DAVFs that highlights some tips and tricks for recognizing useful red flags in the suspicion of DAVFs.

Thrombus Imaging Characteristics and Outcomes in Acute Ischemic Stroke Patients Undergoing Endovascular Treatment.

Background and Purpose- Thrombus imaging characteristics have been reported to be useful to predict functional outcome and reperfusion in acute ischemic stroke. However, conflicting data about this subject exist in patients undergoing endovascular treatment. Therefore, we aimed to evaluate whether thrombus imaging characteristics assessed on computed tomography are associated with outcomes in patients with acute ischemic stroke treated by endovascular treatment. Methods- The MR CLEAN (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry is an ongoing, prospective, and observational study in all centers performing endovascular treatment in the Netherlands. We evaluated associations of thrombus imaging characteristics with the functional outcome (modified Rankin Scale at 90 days), mortality, reperfusion, duration of endovascular treatment, and symptomatic intracranial hemorrhage using univariable and multivariable regression models. Thrombus characteristics included location, clot burden score (CBS), length, relative and absolute attenuation, perviousness, and distance from the internal carotid artery terminus to the thrombus. All characteristics were assessed on thin-slice (≤2.5 mm) noncontrast computed tomography and computed tomography angiography, acquired within 30 minutes from each other. Results- In total, 408 patients were analyzed. Thrombus with distal location, higher CBS, and shorter length were associated with better functional outcome (adjusted common odds ratio, 3.3; 95% CI, 2.0-5.3 for distal M1 occlusion compared with internal carotid artery occlusion; adjusted common odds ratio, 1.15; 95% CI, 1.07-1.24 per CBS point; and adjusted common odds ratio, 0.96; 95% CI, 0.94-0.99 per mm, respectively) and reduced duration of endovascular procedure (adjusted coefficient B, -14.7; 95% CI, -24.2 to -5.1 for distal M1 occlusion compared with internal carotid artery occlusion; adjusted coefficient B, -8.5; 95% CI, -14.5 to -2.4 per CBS point; and adjusted coefficient B, 7.3; 95% CI, 2.9-11.8 per mm, respectively). Thrombus perviousness was associated with better functional outcome (adjusted common odds ratio, 1.01; 95% CI, 1.00-1.02 per Hounsfield units increase). Distal thrombi were associated with successful reperfusion (adjusted odds ratio, 2.6; 95% CI, 1.4-4.9 for proximal M1 occlusion compared with internal carotid artery occlusion). Conclusions- Distal location, higher CBS, and shorter length are associated with better functional outcome and faster endovascular procedure. Distal thrombus is strongly associated with successful reperfusion, and a pervious thrombus is associated with better functional outcome.

Imaging Patterns of Toxic and Metabolic Brain Disorders.

Toxic and metabolic brain disorders are relatively uncommon diseases that affect the central nervous system, but they are important to recognize as they can lead to catastrophic outcomes if not rapidly and properly managed. Imaging plays a key role in determining the most probable diagnosis, pointing to the next steps of investigation, and providing prognostic information. The majority of cases demonstrate bilateral and symmetric involvement of structures at imaging, affecting the deep gray nuclei, cortical gray matter, and/or periventricular white matter, and some cases show specific imaging manifestations. When an appropriate clinical situation suggests exogenous or endogenous toxic effects, the associated imaging pattern usually indicates a restricted group of diagnostic possibilities. Nonetheless, toxic and metabolic brain disorders in the literature are usually approached in the literature by starting with common causal agents and then reaching imaging abnormalities, frequently mixing many different possible manifestations. Conversely, this article proposes a systematic approach to address this group of diseases based on the most important imaging patterns encountered in clinical practice. Each pattern is suggestive of a most likely differential diagnosis, which more closely resembles real-world scenarios faced by radiologists. Basic pathophysiologic concepts regarding cerebral edemas and their relation to imaging are introduced-an important topic for overall understanding. The most important imaging patterns are presented, and the main differential diagnosis for each pattern is discussed. Online supplemental material is available for this article. ©RSNA, 2019.

Neuromyelitis Optica Spectrum Disorders: Spectrum of MR Imaging Findings and Their Differential Diagnosis.

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder for which the aquaporin-4 (AQP4) water channels are the major target antigens. Advances in the understanding of NMO have clarified several points of its pathogenesis, clinical manifestations, and imaging patterns. A major advance was the discovery of the AQP4 antibody, which is highly specific for this disorder. Descriptions of new clinical and radiologic features in seropositive patients have expanded the spectrum of NMO, and the term NMO spectrum disorder (NMOSD) has been adopted. NMOSD is now included in a widening list of differential diagnoses. Acknowledgment of NMOSD imaging patterns and their mimicry of disorders has been crucial in supporting early NMOSD diagnosis, especially for unusual clinical manifestations of this demyelinating disease. This pictorial review summarizes the wide imaging spectrum of NMOSD and its differential diagnosis, as well as its historical evolution, pathophysiology, and clinical manifestations. ©RSNA, 2018.

Imaging of Creutzfeldt-Jakob Disease: Imaging Patterns and Their Differential Diagnosis.

Diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) remains a challenge because of the large variability of the clinical scenario, especially in its early stages, which may mimic several reversible or treatable disorders. The molecular basis of prion disease, as well as its brain propagation and the pathogenesis of the illness, have become better understood in recent decades. Several reports have listed recognizable clinical features and paraclinical tests to supplement the replicable diagnostic criteria in vivo. Nevertheless, we lack specific data about the differential diagnosis of CJD at imaging, mainly regarding those disorders evolving with similar clinical features (mimicking disorders). This review provides an update on the neuroimaging patterns of sCJD, emphasizing the relevance of magnetic resonance (MR) imaging, summarizing the clinical scenario and molecular basis of the disease, and highlighting clinical, genetic, and imaging correlations in different subtypes of prion diseases. A long list of differential diagnoses produces a comprehensive pictorial review, with the aim of enabling radiologists to identify typical and atypical patterns of sCJD. This review reinforces distinguishable imaging findings and confirms diffusion-weighted imaging (DWI) features as pivotal in the diagnostic workup of sCJD, as these findings enable radiologists to reliably recognize this rare but invariably lethal disease. A probable diagnosis is justified when expected MR imaging patterns are demonstrated and CJD-mimicking disorders are confidently ruled out. ©RSNA, 2017.

The effect of kinetic heat shock on bovine oocyte maturation and subsequent gene expression of targeted genes.

The exposure of oocytes to heat stress during the maturation process results in harmful effects to their internal organelles, low fertilization capability and higher embryonic losses. In the present experiment the effect of heat shock (HS) during the maturation process was assessed. In Assay 1, oocytes from winter (December-March; n = 100) and summer (June-September; n = 100) months were collected and matured to analyse their HS tolerance. Total RNA was extracted from matured oocytes and cDNA synthesis was performed, followed by qPCR for selected genes (Cx43, CDH1, DNMT1, HSPA14), compared with two reference genes (GAPDH and SDHA). In Assay 2, oocytes collected during the winter were subjected to kinetic HS by stressing them at 39.5°C for 6, 12, 18 or 24 h and were afterwards matured at control temperature (38.5°C), and subsequently subjected to the previously described gene analysis procedure. Results of Assay 1 show that summer-collected oocytes exhibited lower maturation rate than winter-collected oocytes, which may be due to the down-regulation of the HSPA 14 gene. Assay 2 showed that 6 h of HS had no effect on gene regulation. CDH1 and DNMT1 up-regulation was observed starting at 12 h, which may represent the effect of heat shock on oocyte development.

Extracellular calcium regulates protein tyrosine phosphorylation through calcium-sensing receptor (CaSR) in stallion sperm.

Protein tyrosine phosphorylation (PY), a hallmark of sperm capacitation, is inhibited by extracellular calcium in stallion sperm. The objective of this study was to determine the presence and influence of the calcium-sensing receptor (CaSR) in this phenomenon. First, the presence of the CaSR was demonstrated in stallion sperm. We then tested its function in these gametes using its inhibitor NPS2143 or its agonist AC34356. Sperm were capacitated for 4 hr in modified Whitten's medium with 25 mM bicarbonate plus NPS2143 and 2.4 mM calcium or AC34356 alone, followed by analysis of PY. Inhibition of CaSR with NPS2143 prevented the calcium-dependent PY inhibition in a dose-dependent manner (5, 10, and 15 µM) whereas AC34356 (100 µM) inhibited PY similarly to calcium. Stallion sperm motility and viability significantly decreased in presence of 15 µM of NPS2143 whereas only sperm motility decreased with 100 µM of AC34356. CaSR function was also studied in the complete absence of calcium by including 2 mM ethylene glycol tetraacetic acid (EGTA); under these conditions, AC34356 again inhibited PY, but this time induced a significant increase in sperm motility. Inhibition of calmodulin by W-7 did not recover the AC34356-mediated PY inhibition. When stallion sperm were incubated under capacitating conditions (calcium, bicarbonate, plus bovine serum albumin) at elevated pH (7.9 or 8.5) AC34356 did not block PY. These results thus elucidate the effect of extracellular conditions on the regulation of CaSR, and point to its modulatory role on stallion sperm PY, motility, and viability. Mol. Reprod. Dev. 83: 236-245, 2016. © 2016 Wiley Periodicals, Inc.