Imaging of the Acutely Injured Hip.

Acute hip pain following injury more commonly originates locally in and around the hip joint rather than being referred from the lumbar spine, sacroiliac joints, groin, or pelvis. Clinical assessment can usually localize the pain source to the hip region. Thereafter, imaging helps define the precise cause of acute hip pain. This review discusses the imaging of common causes of acute hip pain following injury in adults, addressing injuries in and around the hip joint. Pediatric and postsurgical causes of hip pain following injury are not discussed.

Denoising of three-dimensional fast spin echo magnetic resonance images of knee joints using spatial-variant noise-relevant residual learning of convolution neural network.

PURPOSE: Two-dimensional (2D) fast spin echo (FSE) techniques play a central role in the clinical magnetic resonance imaging (MRI) of knee joints. Moreover, three-dimensional (3D) FSE provides high-isotropic-resolution magnetic resonance (MR) images of knee joints, but it has a reduced signal-to-noise ratio compared to 2D FSE. Deep-learning denoising methods are a promising approach for denoising MR images, but they are often trained using synthetic noise due to challenges in obtaining true noise distributions for MR images. In this study, inherent true noise information from two number of excitations (2-NEX) acquisition was used to develop a deep-learning model based on residual learning of convolutional neural network (CNN), and this model was used to suppress the noise in 3D FSE MR images of knee joints. METHODS: A deep learning-based denoising method was developed. The proposed CNN used two-step residual learning over parallel transporting and residual blocks and was designed to comprehensively learn real noise features from 2-NEX training data. RESULTS: The results of an ablation study validated the network design. The new method achieved improved denoising performance of 3D FSE knee MR images compared with current state-of-the-art methods, based on the peak signal-to-noise ratio and structural similarity index measure. The improved image quality after denoising using the new method was verified by radiological evaluation. CONCLUSION: A deep CNN using the inherent spatial-varying noise information in 2-NEX acquisitions was developed. This method showed promise for clinical MRI assessments of the knee, and has potential applications for the assessment of other anatomical structures.

Evidence accumulation is biased by motivation: A computational account.

To make good judgments people gather information. An important problem an agent needs to solve is when to continue sampling data and when to stop gathering evidence. We examine whether and how the desire to hold a certain belief influences the amount of information participants require to form that belief. Participants completed a sequential sampling task in which they were incentivized to accurately judge whether they were in a desirable state, which was associated with greater rewards than losses, or an undesirable state, which was associated with greater losses than rewards. While one state was better than the other, participants had no control over which they were in, and to maximize rewards they had to maximize accuracy. Results show that participants' judgments were biased towards believing they were in the desirable state. They required a smaller proportion of supporting evidence to reach that conclusion and ceased gathering samples earlier when reaching the desirable conclusion. The findings were replicated in an additional sample of participants. To examine how this behavior was generated we modeled the data using a drift-diffusion model. This enabled us to assess two potential mechanisms which could be underlying the behavior: (i) a valence-dependent response bias and/or (ii) a valence-dependent process bias. We found that a valence-dependent model, with both a response bias and a process bias, fit the data better than a range of other alternatives, including valence-independent models and models with only a response or process bias. Moreover, the valence-dependent model provided better out-of-sample prediction accuracy than the valence-independent model. Our results provide an account for how the motivation to hold a certain belief decreases the need for supporting evidence. The findings also highlight the advantage of incorporating valence into evidence accumulation models to better explain and predict behavior.

Radiological Advances in Pancreatic Islet Transplantation.

Type 1 diabetes mellitus (T1DM) is characterized by hyperglycemia, owing to the loss of pancreatic ß cells in response to an autoimmune reaction leading to a state of absolute insulin deficiency. T1DM treatment is shifting from exogenous insulin replacement therapy toward pancreatic ß-cell replacement, to restore physiologically responsive insulin secretion to variations in blood glucose levels. ß-cell replacement strategies include human whole pancreas transplantation, islet transplantation with cell encapsulation and bioengineered pancreas. Interventional radiology and imaging modalities including positron emission tomography, single-photon emission computed tomography, magnetic resonance imaging, ultrasonography, and molecular imaging are imperative to enable successful ß-cell replacement. Herein, the role of radiological modalities in the treatment of T1DM and its prospective use for noninvasive post-transplantation graft monitoring is discussed.

Anchor-balloon technique to facilitate stent delivery via the GuideLiner catheter in percutaneous coronary intervention.

AIM: The GuideLiner (GL) is a widely used catheter primarily in complex percutaneous coronary intervention (PCI). Deep seating of the GL and distal stent placement may be facilitated by the anchor-balloon technique (ABT). METHODS: We aimed to prospectively analyze procedural details, technical success, complications and in-hospital outcome in patients who underwent PCI using the GL catheter and the ABT. RESULTS: A total of 118 patients underwent PCI with the aid of the GL and ABT. Procedure success rate was 95% (112/118) and only seven patients (5.9%) encountered complications. ABT was indicated and successfully used in 29 patients (25%). CONCLUSION: GL and ABT successfully aided stent delivery in unfavorable and heavily calcified lesions which otherwise may have been considered unsuitable for PCI.

What experimental experience affects dogs' comprehension of human communicative actions?

Studies of dogs report that individuals reliably respond to the goal-directed communicative actions (e.g., pointing) of human experimenters. All of these studies use some version of a multi-trial approach, thereby allowing for the possibility of rapid learning within an experimental session. The experiments reported here ask whether dogs can respond correctly to a communicative action based on only a single presentation, thereby eliminating the possibility of learning within the experimental context. We tested 173 dogs. For each dog reaching our test criteria, we used a single presentation of six different goal-directed actions within a session, asking whether they correctly follow to a target goal (container with concealed food) a (1) distal hand point, (2) step toward one container, (3) hand point to one container followed by step toward the other, (4) step toward one container and point to the other, (5) distal foot point with the experimenter's hands free, and (6) distal foot point with the experimenter's hands occupied. Given only a single presentation, dogs selected the correct container when the experimenter hand pointed, foot pointed with hands occupied, or stepped closer to the target container, but failed on the other actions, despite using the same method. The fact that dogs correctly followed foot pointing with hands occupied, but not hands free, suggests that they are sensitive to environmental constraints, and use this information to infer rational, goal-directed action. We discuss these results in light of the role of experience in recognizing communicative gestures, as well as the significance of coding criteria for studies of canine competence.

Evidence of an evolutionary precursor to human language affixation in a non-human primate.

Human language, and grammatical competence in particular, relies on a set of computational operations that, in its entirety, is not observed in other animals. Such uniqueness leaves open the possibility that components of our linguistic competence are shared with other animals, having evolved for non-linguistic functions. Here, we explore this problem from a comparative perspective, asking whether cotton-top tamarin monkeys (Saguinus oedipus) can spontaneously (no training) acquire an affixation rule that shares important properties with our inflectional morphology (e.g. the rule that adds -ed to create the past tense, as in the transformation of walk into walk-ed). Using playback experiments, we show that tamarins discriminate between bisyllabic items that start with a specific 'prefix' syllable and those that end with the same syllable as a 'suffix'. These results suggest that some of the computational mechanisms subserving affixation in a diversity of languages are shared with other animals, relying on basic perceptual or memory primitives that evolved for non-linguistic functions.