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https://www.readbyqxmd.com/read/28334960/neural-mechanisms-of-reinforcement-learning-in-unmedicated-patients-with-major-depressive-disorder
#1
Marcus Rothkirch, Jonas Tonn, Stephan Köhler, Philipp Sterzer
According to current concepts, major depressive disorder is strongly related to dysfunctional neural processing of motivational information, entailing impairments in reinforcement learning. While computational modelling can reveal the precise nature of neural learning signals, it has not been used to study learning-related neural dysfunctions in unmedicated patients with major depressive disorder so far. We thus aimed at comparing the neural coding of reward and punishment prediction errors, representing indicators of neural learning-related processes, between unmedicated patients with major depressive disorder and healthy participants...
February 20, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28334372/simulations-imaging-and-modeling-a-unique-theme-for-an-undergraduate-research-program-in-biomechanics
#2
Stephanie M George, Zachary J Domire
As the reliance on computational models to inform experiments and evaluate medical devices grows, the demand for students with modeling experience will grow. In this paper, we report on the three year experience of a National Science Foundation funded Research Experiences for Undergraduates (REU) based on the theme simulations, imaging, and modeling in biomechanics. While directly applicable to REU sites, our findings also apply to those creating other types of summer undergraduate research programs. The objective of the paper is to examine if a theme of simulations, imaging, and modeling will improve students' understanding of the important topic of modeling, provide an overall positive research experience, and provide an interdisciplinary experience...
March 23, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28333629/curl-constrained-gradient-estimation-for-image-recovery-from-highly-incomplete-spectral-data
#3
Chiara Ravazzi, Giulio Coluccia, Enrico Magli
In this paper, we introduce new gradient-based methods for image recovery from a small collection of spectral coefficients of the Fourier transform, which is of particular interest for several scanning technologies, such as magnetic resonance imaging. Since gradients of a medical image are much more sparse or compressible than the corresponding image, classical `1- minimization methods have been used to recover these relative differences. The image values can then be obtained by integration algorithms imposing boundary constraints...
March 21, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28331828/radiomics-of-pulmonary-nodules-and-lung-cancer
#4
REVIEW
Ryan Wilson, Anand Devaraj
The large number of indeterminate pulmonary nodules encountered incidentally or during CT-based lung screening provides considerable diagnostic and management challenges. Conventional nodule evaluation relies on visually identifiable discriminators such as size and speculation. These visible nodule features are however small in number and subject to considerable interpretation variability. With the development of novel targeted therapies for lung cancer the diagnosis and characterization of early stage lung tumours has never been more important...
February 2017: Translational Lung Cancer Research
https://www.readbyqxmd.com/read/28329105/medical-three-dimensional-printing-opens-up-new-opportunities-in-cardiology-and-cardiac-surgery
#5
Thomas Bartel, Andrew Rivard, Alejandro Jimenez, Carlos A Mestres, Silvana Müller
Advanced percutaneous and surgical procedures in structural and congenital heart disease require precise pre-procedural planning and continuous quality control. Although current imaging modalities and post-processing software assists with peri-procedural guidance, their capabilities for spatial conceptualization remain limited in two- and three-dimensional representations. In contrast, 3D printing offers not only improved visualization for procedural planning, but provides substantial information on the accuracy of surgical reconstruction and device implantations...
February 16, 2017: European Heart Journal
https://www.readbyqxmd.com/read/28328739/effects-of-a-brief-cognitive-behavioural-therapy-group-intervention-on-baseline-brain-perfusion-in-adolescents-with-major-depressive-disorder
#6
Zrinka Sosic-Vasic, Birgit Abler, Georg Grön, Paul Plener, Joana Straub
A number of neuroimaging studies have identified altered regional cerebral blood flow (rCBF) related to major depressive disorder (MDD) in adult samples, particularly in the lateral prefrontal, cingular and temporal regions. In contrast, neuroimaging investigations in adolescents with MDD are rare, although investigating young patients during a significant period of brain maturation might offer valuable insights into the neural mechanisms of MDD. We acquired perfusion images obtained with continuous arterial spin labelling in 21 medication-naive adolescents with MDD before and after a five-session cognitive behavioural group therapy (group CBT)...
March 21, 2017: Neuroreport
https://www.readbyqxmd.com/read/28325446/segmentation-of-elastic-fibres-in-images-of-vessel-wall-sections-stained-with-weigert-s-resorcin-fuchsin
#7
Pablo Hernández-Morera, Carlos M Travieso-González, Irene Castaño-González, Blanca Mompeó-Corredera, Francisco Ortega-Santana
BACKGROUND AND OBJECTIVE: The elastic fibres are an essential component of the extracellular matrix in blood vessel walls that allows a long-range of deformability and passive recoil without energy input. The quantitative determination of elastic fibres will provide information on the state of the vascular wall and to determine the role and behaviour of this key structural element in different physiological and pathological vascular processes. METHODS: We present a segmentation method to identify and quantify elastic fibres based on a local threshold technique and some morphological characteristics measured on the segmented objects that facilitate the discrimination between elastic fibres and other image components...
April 2017: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/28325444/a-numerical-model-for-aggregations-formation-and-magnetic-driving-of-spherical-particles-based-on-openfoam%C3%A2
#8
E G Karvelas, N K Lampropoulos, I E Sarris
BACKGROUND AND OBJECTIVE: This work presents a numerical model for the formation of particle aggregations under the influence of a permanent constant magnetic field and their driving process under a gradient magnetic field, suitably created by a Magnetic Resonance Imaging (MRI) device. METHODS: The model is developed in the OpenFOAM platform and it is successfully compared to the existing experimental and numerical results in terms of aggregates size and their motion in water solutions...
April 2017: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/28322040/design-and-fabrication-of-a-thin-walled-freeform-scaffold-on-the-basis-of-medical-image-data-and-a-3d-printed-template-potential-use-in-bile-duct-regeneration
#9
Suk Hee Park, Bo-Kyeong Kang, Ji Eun Lee, Seung Woo Chun, Kiseok Jang, Youn Hwan Kim, Mi Ae Jeong, Yohan Kim, Kyo Jin Kang, Nak Kyu Lee, Dongho Choi, Han Joon Kim
Three-dimensional (3D) printing, combined with medical imaging technologies, such as computed tomography (CT) and magnetic resonance imaging (MRI), has shown great potential in patient-specific tissue regeneration. Here, we successfully fabricated an ultrathin tubular freeform structure that has a wall thickness of several tens of micrometers and is capable of providing sufficient mechanical flexibility. Such a thin geometry cannot easily be achieved by 3D printing alone; therefore, it was realized through a serial combination of processes that included the 3D printing of a sacrificial template, the dip-coating of the biomaterial, and the removal of the inner template...
March 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28322012/3d-printed-multidrug-eluting-stent-from-graphene-nanoplatelet-doped-biodegradable-polymer-composite
#10
Santosh K Misra, Fatemeh Ostadhossein, Ramya Babu, Joseph Kus, Divya Tankasala, Andre Sutrisno, Kathleen A Walsh, Corinne R Bromfield, Dipanjan Pan
Patients with percutaneous coronary intervention generally receive either bare metal stents or drug-eluting stents to restore the normal blood flow. However, due to the lack of stent production with an individual patient in mind, the same level of effectiveness may not be possible in treating two different clinical scenarios. This study introduces for the first time the feasibility of a patient-specific stenting process constructed from direct 3D segmentation of medical images using direct 3D printing of biodegradable polymer-graphene composite with dual drug incorporation...
March 21, 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28319042/smartphone-application-for-mechanical-quality-assurance-of-medical-linear-accelerator
#11
Hwiyoung Kim, Hyunseok Lee, Jong In Park, Chang Heon Choi, So-Yeon Park, Hee Jung Kim, Young Suk Kim, Sung-Joon Ye
Mechanical quality assurance (QA) of medical linear accelerators consists of time consuming and human-error prone procedures. We developed a smartphone-application system for mechanical QA. The system consists of two smartphones; one attached to the gantry to obtain real-time information on mechanical parameters of medical linear accelerator, and the other to display the real-time information by bluetoothing the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations...
March 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28317922/optical-imaging-of-localized-chemical-events-using-programmable-diamond-quantum-nanosensors
#12
Torsten Rendler, Jitka Neburkova, Ondrej Zemek, Jan Kotek, Andrea Zappe, Zhiqin Chu, Petr Cigler, Jörg Wrachtrup
Development of multifunctional nanoscale sensors working under physiological conditions enables monitoring of intracellular processes that are important for various biological and medical applications. By attaching paramagnetic gadolinium complexes to nanodiamonds (NDs) with nitrogen-vacancy (NV) centres through surface engineering, we developed a hybrid nanoscale sensor that can be adjusted to directly monitor physiological species through a proposed sensing scheme based on NV spin relaxometry. We adopt a single-step method to measure spin relaxation rates enabling time-dependent measurements on changes in pH or redox potential at a submicrometre-length scale in a microfluidic channel that mimics cellular environments...
March 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28315426/vascular-patterning-in-human-heterotopic-ossification
#13
Margaret Cocks, Aditya Mohan, Carolyn A Meyers, Catherine Ding, Benjamin Levi, Edward McCarthy, Aaron W James
Heterotopic ossification (HO, also termed myositis ossificans) is the formation of extra-skeletal bone in muscle and soft tissues. HO is a tissue repair process gone awry, and is a common complication of surgery and traumatic injury. Medical strategies to prevent and treat HO fall well short of addressing the clinical need. Better characterization of the tissues supporting HO is critical to identifying therapies directed against this common and sometimes devastating condition. The physiologic processes of osteogenesis and angiogenesis are highly coupled and interdependent...
March 14, 2017: Human Pathology
https://www.readbyqxmd.com/read/28303474/respiratory-motion-reduction-with-a-dual-gating-approach-in-myocardial-perfusion-spect-effect-on-left-ventricular-functional-parameters
#14
Matti J Kortelainen, Tuomas M Koivumäki, Marko J Vauhkonen, Marja K Hedman, Satu T J Kärkkäinen, Juanita Niño Quintero, Mikko A Hakulinen
BACKGROUND: Respiratory motion (RM) complicates the analysis of myocardial perfusion (MP) single-photon emission computed tomography (SPECT) images. The effects of RM on left ventricular (LV) functional variables have not been thoroughly investigated. METHODS AND RESULTS: Thoracic electrical bioimpedance and electrocardiographic signals were recorded from eighteen patients undergoing the rest phase of a 1-day stress/rest cardiac-gated MP-SPECT examination. The signals and list-mode emission data were retrospectively processed to yield standard cardiac- and dual-gated (respiratory and cardiac gating) image sets applying a novel algorithm...
March 16, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28297296/development-of-a-universal-medical-x-ray-imaging-phantom-prototype
#15
Annemari Groenewald, Willem A Groenewald
Diagnostic X-ray imaging depends on the maintenance of image quality that allows for proper diagnosis of medical conditions. Maintenance of image quality requires quality assurance programs on the various X-ray modalities, which consist of projection radiography (including mobile X-ray units), fluoroscopy, mammography, and computed tomography (CT) scanning. Currently a variety of modality-specific phantoms are used to perform quality assurance (QA) tests. These phantoms are not only expensive, but suitably trained personnel are needed to successfully use them and interpret the results...
November 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28294462/disruption-of-white-matter-structural-integrity-and-connectivity-in-posttraumatic-stress-disorder-a-tbss-and-tractography-study
#16
Elizabeth A Olson, Jiaolong Cui, Rena Fukunaga, Lisa D Nickerson, Scott L Rauch, Isabelle M Rosso
BACKGROUND: Most studies of brain white matter (WM) in posttraumatic stress disorder (PTSD) have focused on combat trauma, and often were confounded by neurological and substance dependence comorbidity. This study used tract-based spatial statistics (TBSS) and probabilistic tractography to characterize WM microstructure in a mixed-sex community sample of PTSD patients exposed to diverse and multiple traumas, and in trauma-exposed normal comparison (TENC) subjects. METHODS: TBSS compared diffusion measures between 20 adults with DSM-IV PTSD and 17 TENC, using a whole-brain voxel-wise approach...
March 15, 2017: Depression and Anxiety
https://www.readbyqxmd.com/read/28293752/acoustic-emission-signatures-during-failure-of-vertebra-and-long-bone
#17
Brian D Goodwin, Frank A Pintar, Narayan Yoganandan
Clinical classification of an injury has traditionally involved medical imaging, patient history, and physical examination. The pathogenesis or process of injury has been viewed as a crucial component to estimating fracture stability and direct treatment. However, injury classification systems generally exclude pathogenesis and injury mechanisms because these components are often difficult to elucidate. Furthermore, the development of bone damage relative to the mechanical response is difficult to quantify, which limits the ability to define injury and develop injury criteria...
March 14, 2017: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/28293473/separating-generalized-anxiety-disorder-from-major-depression-using-clinical-hormonal-and-structural-mri-data-a-multimodal-machine-learning-study
#18
Kevin Hilbert, Ulrike Lueken, Markus Muehlhan, Katja Beesdo-Baum
BACKGROUND: Generalized anxiety disorder (GAD) is difficult to recognize and hard to separate from major depression (MD) in clinical settings. Biomarkers might support diagnostic decisions. This study used machine learning on multimodal biobehavioral data from a sample of GAD, MD and healthy subjects to differentiate subjects with a disorder from healthy subjects (case-classification) and to differentiate GAD from MD (disorder-classification). METHODS: Subjects with GAD (n = 19), MD without GAD (n = 14), and healthy comparison subjects (n = 24) were included...
March 2017: Brain and Behavior
https://www.readbyqxmd.com/read/28293255/sparse-codebook-model-of-local-structures-for-retrieval-of-focal-liver-lesions-using-multiphase-medical-images
#19
Jian Wang, Xian-Hua Han, Yingying Xu, Lanfen Lin, Hongjie Hu, Chongwu Jin, Yen-Wei Chen
Characterization and individual trait analysis of the focal liver lesions (FLL) is a challenging task in medical image processing and clinical site. The character analysis of a unconfirmed FLL case would be expected to benefit greatly from the accumulated FLL cases with experts' analysis, which can be achieved by content-based medical image retrieval (CBMIR). CBMIR mainly includes discriminated feature extraction and similarity calculation procedures. Bag-of-Visual-Words (BoVW) (codebook-based model) has been proven to be effective for different classification and retrieval tasks...
2017: International Journal of Biomedical Imaging
https://www.readbyqxmd.com/read/28290736/accuracy-and-reliability-of-marker-based-approaches-to-scale-the-pelvis-thigh-and-shank-segments-in-musculoskeletal-models
#20
Hans Kainz, Hoa Hoang, Chris Stockton, Roslyn R Boyd, David G Lloyd, Christopher P Carty
Gait analysis together with musculoskeletal modelling is widely used for research. In the absence of medical images, surface marker locations are used to scale a generic model to the individual's anthropometry. Studies evaluating the accuracy and reliability of different scaling approaches in a paediatric and/or clinical population have not yet been conducted and, therefore, formed the aim of this study. Magnetic resonance images (MRI) and motion capture data were collected from twelve participants with cerebral palsy and six typically developed participants...
March 14, 2017: Journal of Applied Biomechanics
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