STATISTICAL COMPARISON OF THE KNEE CONTACT FORCES AND KNEE JOINT MOMENTS TO EVALUATE THE LOADING IN THE KNEE WITH FRONTAL PLANE MALALIGNMENT DURING WALKING

In children and adolescent with valgus malalignment the loading is shifted to the lateral compartment. The aim of this study was to investigate the numerical linear relationship between knee joint moments and medial and lateral knee contact forces in children and adolescents with frontal plane malalignment and typically developed controls. In the 2nd half of stance a significant medium linear relationship was found between the knee adduction moment and the medial and lateral knee contact forces. These results lead to the assumption that the loading in the knee joint in children and adolescent should be analyzed by calculating knee contact forces rather than knee joint moments

Artefaktreduktion und Verbesserung der Bildqualität mittels iterativem Bildrekonstruktionsalgorithmus in der CT-Bildgebung des Neurocraniums

Zielsetzung: Klinisch-prospektiver Vergleich der resultierenden Bildqualität des modellbasierten iterativen Rekonstruktionsalgorithmus MBIR mit derjenigen des iterativen Standard-Algorithmus ASiR bei der Bildberechnung aus CT-Rohdaten am speziellen Beispiel der sehr häufig durchgeführten und klinisch relevanten, aber oft durch Artefakte beeinträchtigten CT-Untersuchung des Neurocraniums. Material und Methoden: 100 Patienten erhielten an einem 64-Zeilen CT-Gerät (CT750HD Discovery, GE Healthcare Waukesha, WI, USA) eine klinisch indizierte native Untersuchung des Schädels nach institutsinternem Standardprotokoll (120kV Röhrenspannung, 50-260 mAs Röhrenstrommodulation, 20mm Detektorkollimation, 0,984 Pitchfaktor, 1,0 s Rotationsdauer). Die Rohdatensätze wurden sowohl mittels ASiR als auch mit MBIR zu Dünnschicht-Bildserien rekonstruiert, anonymisiert und daraus zur Betrachtung geeignete Bildserien mit jeweils 2,5 mm Schichtdicke multiplanar reformatiert. Signal-to-noise ratio (SNR) und Contrast-to-noise ratio (CNR) wurden aus Dichtewerten an jeweils identischer Position standardisiert supra- und infratentoriell in grauer und weißer Substanz sowie in Liquor errechnet. Unabhängig voneinander und bezüglich des verwendeten Rekonstruktionsalgorithmus verblindet beurteilten zwei Radiologen qualitativ anhand einer 5-Punkte-Skala (0: inakzeptabel, 1: unterdurchschnittlich, 2: durchschnittlich, 3: überdurchschnittlich, 4: exzellent) die Darstellung anatomischer Strukturen und den Einfluss von Artefakten auf die allgemeine Bildqualität. Die Signifikanz wurde mittels ANOVA und Mann-Whitney-U-Test geprüft und die statistische Übereinstimmung mit ICC korreliert. Ergebnisse: Im Vergleich zu ASiR resultierte MBIR in einer besseren allgemeinen Bildqualität (Median: MBIR = 2, ASiR = 1, p<0.01). Zudem reduzierte MBIR die Artefakte bei der Darstellung anatomischer Strukturen (Median: MBIR= 3, ASiR = 2, p<0,01). Für MBIR war SNR jeweils durchschnittlich um 28,9% und CNR um 37,29% höher als für ASiR (p<0,01). Schlussfolgerung: MBIR zeigte gegenüber ASiR jeweils signifikant sowohl eine Verbesserung der Bildqualität als auch eine Reduktion der Artefakte. Somit könnte der Einsatz von MBIR im klinischen Alltag bei gleicher diagnostischer Bildqualität eine deutliche Senkung der Strahlenexposition durch medizinische Untersuchungen bewirken. Dieses Potenzial wird derzeit noch durch die deutlich längere Rekonstruktionszeit mit MBIR limitiert (ASIR ca. 49 s, MBIR ca. 1921 s pro Bildserie)

Identification of Patients with Similar Gait Compensating Strategies Due to Unilateral Hip Osteoarthritis and the Effect of Total Hip Replacement: A Secondary Analysis

Despite good clinical functional outcome, deficits in gait biomechanics exist 2 years after total hip replacement surgery. The aims of this research were (1) to group patients showing similar gait adaptations to hip osteoarthritis and (2) to investigate the effect of the surgical treatment on gait kinematics and external joint moments. In a secondary analysis, gait data of 51 patients with unilateral hip osteoarthritis were analyzed. A k-means cluster analysis was performed on scores derived via a principal component analysis of the gait kinematics. Preoperative and postoperative datasets were statistically tested between clusters and 46 healthy controls. The first three principal components incorporated hip flexion/extension, pelvic tilt, foot progression angle and thorax tilt. Two clusters were discriminated best by the peak hip extension during terminal stance. Both clusters deviated from healthy controls in spatio-temporal, kinematic and kinetic parameters. The cluster with less hip extension deviated significantly more. The clusters improved postoperatively but differences to healthy controls were still present one year after surgery. A poor preoperative gait pattern in patients with unilateral hip osteoarthritis is associated with worse gait kinematics after total hip replacement. Further research should focus on the identification of patients who can benefit from an adapted or individualized rehabilitation program

Improving Image Quality of Sparse-view Lung Cancer CT Images with a Convolutional Neural Network

Purpose: To improve the image quality of sparse-view computed tomography (CT) images with a U-Net for lung cancer detection and to determine the best trade-off between number of views, image quality, and diagnostic confidence. Methods: CT images from 41 subjects (34 with lung cancer, seven healthy) were retrospectively selected (01.2016-12.2018) and forward projected onto 2048-view sinograms. Six corresponding sparse-view CT data subsets at varying levels of undersampling were reconstructed from sinograms using filtered backprojection with 16, 32, 64, 128, 256, and 512 views, respectively. A dual-frame U-Net was trained and evaluated for each subsampling level on 8,658 images from 22 diseased subjects. A representative image per scan was selected from 19 subjects (12 diseased, seven healthy) for a single-blinded reader study. The selected slices, for all levels of subsampling, with and without post-processing by the U-Net model, were presented to three readers. Image quality and diagnostic confidence were ranked using pre-defined scales. Subjective nodule segmentation was evaluated utilizing sensitivity (Se) and Dice Similarity Coefficient (DSC) with 95% confidence intervals (CI). Results: The 64-projection sparse-view images resulted in Se = 0.89 and DSC = 0.81 [0.75,0.86] while their counterparts, post-processed with the U-Net, had improved metrics (Se = 0.94, DSC = 0.85 [0.82,0.87]). Fewer views lead to insufficient quality for diagnostic purposes. For increased views, no substantial discrepancies were noted between the sparse-view and post-processed images. Conclusion: Projection views can be reduced from 2048 to 64 while maintaining image quality and the confidence of the radiologists on a satisfactory level

Submillisievert Computed Tomography of the Chest Using Model-Based Iterative Algorithm: Optimization of Tube Voltage With Regard to Patient Size

Objective: The aim of this study was to define optimal tube potential for soft tissue and vessel visualization in dose-reduced chest CT protocols using model-based iterative algorithm in average and overweight patients. Methods: Thirty-six patients receiving chest CTaccording to 3 protocols (120 kVp/noise index [NI], 60;100 kVp/NI, 65;80 kVp/NI, 70) were included in this prospective study, approved by the ethics committee. Patients' physical parameters and dose descriptors were recorded. Images were reconstructed with model-based algorithm. Two radiologists evaluated image quality and lesion conspicuity;the protocols were intraindividually compared with preceding control CT reconstructed with statistical algorithm (120 kVp/NI, 20). Mean and standard deviation of attenuation of the muscle and fat tissues and signal-to-noise ratio of the aorta were measured. Results: Diagnostic images (lesion conspicuity, 95%-100%) were acquired in average and overweight patients at 1.34, 1.02, and 1.08 mGy and at 3.41, 3.20, and 2.88 mGy at 120, 100, and 80 kVp, respectively. Data are given as CT dose index volume values. Conclusions: Model-based algorithm allows for submillisievert chest CT in average patients;the use of 100 kVp is recommended

The first annual meeting of the Nippon Hoken-Gakkai (Insurance Institute of Japan)

The effects of manipulated dental occlusion on body posture has been investigated quite often and discussed controversially in the literature. Far less attention has been paid to the influence of dental occlusion position on human movement. If human movement was analysed, it was mostly while walking and not while running. This study was therefore designed to identify the effect of lower jaw positions on running behaviour according to different dental occlusion positions.Twenty healthy young recreational runners (mean age = 33.9±5.8 years) participated in this study. Kinematic data were collected using an eight-camera Vicon motion capture system (VICON Motion Systems, Oxford, UK). Subjects were consecutively prepared with four different dental occlusion conditions in random order and performed five running trials per test condition on a level walkway with their preferred running shoes. Vector based pattern recognition methods, in particular cluster analysis and support vector machines (SVM) were used for movement pattern identification.Subjects exhibited unique movement patterns leading to 18 clusters for the 20 subjects. No overall classification of the splint condition could be observed. Within individual subjects different running patterns could be identified for the four splint conditions. The splint conditions lead to a more symmetrical running pattern than the control condition.The influence of an occlusal splint on running pattern can be confirmed in this study. Wearing a splint increases the symmetry of the running pattern. A more symmetrical running pattern might help to reduce the risk of injuries or help in performance. The change of the movement pattern between the neutral condition and any of the three splint conditions was significant within subjects but not across subjects. Therefore the dental splint has a measureable influence on the running pattern of subjects, however subjects individuality has to be considered when choosing the optimal splint condition for a specific subject

Optimization of tube voltage in X-ray dark-field chest radiography

Grating-based X-ray dark-field imaging is a novel imaging modality which has been refined during the last decade. It exploits the wave-like behaviour of X-radiation and can nowadays be implemented with existing X-ray tubes used in clinical applications. The method is based on the detection of small-angle X-ray scattering, which occurs e.g. at air-tissue-interfaces in the lung or bone-fat interfaces in spongy bone. In contrast to attenuation-based chest X-ray imaging, the optimal tube voltage for dark-field imaging of the thorax has not yet been examined. In this work, dark-field scans with tube voltages ranging from 60 to 120 kVp were performed on a deceased human body. We analyzed the resulting images with respect to subjective and objective image quality, and found that the optimum tube voltage for dark-field thorax imaging at the used setup is at rather low energies of around 60 to 70 kVp. Furthermore, we found that at these tube voltages, the transmission radiographs still exhibit sufficient image quality to correlate dark-field information. Therefore, this study may serve as an important guideline for the development of clinical dark-field chest X-ray imaging devices for future routine use

ITIH5 mediates epigenetic reprogramming of breast cancer cells

Extracellular matrix (ECM) is known to maintain epithelial integrity. In carcinogenesis ECM degradation triggers metastasis by controlling migration and differentiation including cancer stem cell (CSC) characteristics. The ECM-modulator inter- α-trypsin inhibitor heavy chain family member five (ITIH5) was recently identified as tumor suppressor potentially involved in impairing breast cancer progression but molecular mechanisms underlying its function are still elusive

Acclimation in plants – the Green Hub consortium

Acclimation is the capacity to adapt to environmental changes within the lifetime of an individual. This ability allows plants to cope with the continuous variation in ambient conditions to which they are exposed as sessile organisms. Because environmental changes and extremes are becoming even more pronounced due to the current period of climate change, enhancing the efficacy of plant acclimation is a promising strategy for mitigating the consequences of global warming on crop yields. At the cellular level, the chloroplast plays a central role in many acclimation responses, acting both as a sensor of environmental change and as a target of cellular acclimation responses. In this Perspective article, we outline the activities of the Green Hub consortium funded by the German Science Foundation. The main aim of this research collaboration is to understand and strategically modify the cellular networks that mediate plant acclimation to adverse environments, employing Arabidopsis, tobacco (Nicotiana tabacum) and Chlamydomonas as model organisms. These efforts will contribute to ‘smart breeding’ methods designed to create crop plants with improved acclimation properties. To this end, the model oilseed crop Camelina sativa is being used to test modulators of acclimation for their potential to enhance crop yield under adverse environmental conditions. Here we highlight the current state of research on the role of gene expression, metabolism and signalling in acclimation, with a focus on chloroplast‐related processes. In addition, further approaches to uncovering acclimation mechanisms derived from systems and computational biology, as well as adaptive laboratory evolution with photosynthetic microbes, are highlighted.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Peer Reviewe