Autoadaptive motion modelling for MR-based respiratory motion estimation

This repository contains four T1-weighted 2D MR slice datasets from multiple slice positions covering the entire thorax during free breathing and breath holds. The data was used to evaluate our novel autoadaptive respiratory motion model which we proposed in [1]. In particular, the datasets contain the following: Acquisition of all sagittal slice positions covering the thorax and one coronal slice position acquired during a breath hold. Results of registration between adjacent sagittal slice positions [control point displacements (cpp) and displacement fields (dfs)] 40 dynamic acquisitions of each slice position also present in the breath-hold acquired during free breathing. Results of registration of the dynamic acquisitions to the respective breath-holds slices (cpp's and dfs's). The data is divided into 4 zip files, each containing the data of one volunteer. The folder structure for each is as follows: |-- bhs (breath hold data) | |-- images (images) | | |-- cor | | `-- sag | `-- mfs_slpos2slpos (registration results) | `-- sag `-- dyn (dynamic free-breathing data) |-- images (images) | |-- cor | `-- sag `-- mfs_tpos2tpos (registration results) |-- cor `-- sag Please, see our publication [1] for details on the acquisition sequence and registration used. -- [1]: CF Baumgartner, C Kolbitsch, JR McClelland, D Rueckert, AP King, Autoadaptive motion modelling for MR-based respiratory motion estimation, Medical Image Analysis (2016), http://dx.doi.org/10.1016/j.media.2016.06.00

Respiratory motion correction for enhanced quantification of hepatic lesions in simultaneous PET and DCE-MR imaging

Simultaneous positron-emission tomography (PET)-magnetic resonance (MR) imaging is a hybrid technique in oncological hepatic imaging combining soft-tissue and functional contrast of dynamic contrast enhanced MR (DCE-MR) with metabolic information from PET. In this context, respiratory motion represents a major challenge by introducing blurring, artifacts and misregistration in the liver. In this work, we propose a free-breathing 3D non-rigid respiratory motion correction framework for simultaneously acquired DCE-MR and PET data, which makes use of higher spatial resolution MR data to derive motion information used directly during image reconstruction to minimize image blurring and motion artifacts. The main aim was to increase contrast of hepatic metastases to improve their detection and characterization. DCE-MR data were acquired at 3T through a golden radial phase encoding scheme, enabling derivation of motion fields. These were used in the motion compensated image reconstruction of DCE-MR time-series (48 time-points, 6 s temporal resolution, 1.5 mm isotropic spatial resolution) and 3D PET activity map, which was subsequently interpolated to the DCE-MR resolution. The extended Tofts model was fitted to DCE-MR data, obtaining functional parametric maps related to perfusion such as the endothelial permeability ( Kt ). Fifty-seven hepatic metastases were identified and analyzed. Quantitative evaluations of motion correction in PET images demonstrated average percentage increases of 16% ± 5% (mean ± SD) in Contrast (C), 18% ± 6% in SUVmean and 14% ± 2% in SUVmax, while DCE-MR and Kt scored contrast-to-noise-ratio increases of 64% ± 3% and 90% ± 6%, respectively. Motion-corrected data visually showed improved image contrast of hepatic metastases and effectively reduced blurring and motion artefacts. Scatter plots of SUVmean versus Kt suggested that the proposed framework improved differentiation of Kt measurements. The presented motion correction framework for simultaneously acquired PET-DCE-MR data provides accurately aligned images with increased contrast of hepatic lesions allowing for improved detection and characterization.DFG, 289347353, GRK 2260: BIOQIC - BIOphysical Quantitative Imaging Towards Clinical DiagnosisDFG, 372486779, SFB 1340: In vivo Visualisierung der pathologisch veränderten Extrazellulärmatrix „Matrix in Vision

Hypertrophic cardiomyopathy is characterized by alterations of the mitochondrial calcium uniporter complex proteins: insights from patients with aortic valve stenosis versus hypertrophic obstructive cardiomyopathy

Introduction: Hypertrophies of the cardiac septum are caused either by aortic valve stenosis (AVS) or by congenital hypertrophic obstructive cardiomyopathy (HOCM). As they induce cardiac remodeling, these cardiac pathologies may promote an arrhythmogenic substrate with associated malignant ventricular arrhythmias and may lead to heart failure. While altered calcium (Ca2+) handling seems to be a key player in the pathogenesis, the role of mitochondrial calcium handling was not investigated in these patients to date.Methods: To investigate this issue, cardiac septal samples were collected from patients undergoing myectomy during cardiac surgery for excessive septal hypertrophy and/or aortic valve replacement, caused by AVS and HOCM. Septal specimens were matched with cardiac tissue obtained from post-mortem controls without cardiac diseases (Ctrl).Results and discussion: Patient characteristics and most of the echocardiographic parameters did not differ between AVS and HOCM. Most notably, the interventricular septum thickness, diastolic (IVSd), was the greatest in HOCM patients. Histological and molecular analyses showed a trend towards higher fibrotic burden in both pathologies, when compared to Ctrl. Most notably, the mitochondrial Ca2+ uniporter (MCU) complex associated proteins were altered in both pathologies of left ventricular hypertrophy (LVH). On the one hand, the expression pattern of the MCU complex subunits MCU and MICU1 were shown to be markedly increased, especially in AVS. On the other hand, PRMT-1, UCP-2, and UCP-3 declined with hypertrophy. These conditions were associated with an increase in the expression patterns of the Ca2+ uptaking ion channel SERCA2a in AVS (p = 0.0013), though not in HOCM, compared to healthy tissue. Our data obtained from human specimen from AVS or HOCM indicates major alterations in the expression of the mitochondrial calcium uniporter complex and associated proteins. Thus, in cardiac septal hypertrophies, besides modifications of cytosolic calcium handling, impaired mitochondrial uptake might be a key player in disease progression

Dynamic Adaptation of Content and Structure in Electronic Encyclopaedias

Adaptive functionality has been applied successfully in many areas ranging from user interfaces to hypermedia systems. Digital libraries and electronic encyclopaedias, however, have rarely made use of the power of adaptation. In this paper, an approach to include adaptation into encyclopaedic environments is presented. The proposal covers a set of adaptation techniques. They enable the system to explain technical terms and replace domain specific expressions with "plain" words automatically. Moreover, specific terms can be linked to further articles automatedly. Blacklisting, whitelisting and general link alteration are employed in order to assure quality standards and to provide users with more appropriate hyperlinks. With navigation support based on the automatic insertion of trails and suggestions of potentially interesting articles, the users' navigation in encyclopaedias can be facilitated. A first version has been implemented in project "Alexander" and has been made available to a limited public. The system is based on a traditional client-server architecture, where the server-side components perform the actual adaptation. Details of this pilot project are provided

Rozzle: De-Cloaking Internet Malware

Abstract—JavaScript-based malware attacks have increased in recent years and currently represent a significant threat to the use of desktop computers, smartphones, and tablets. While static and runtime methods for malware detection have been proposed in the literature, both on the client side, for just-intime in-browser detection, as well as offline, crawlerbased malware discovery, these approaches encounter the same fundamental limitation. Web-based malware tends to be environment-specific, targeting a particular browser, often attacking specific versions of installed plugins. This targeting occurs because the malware exploits vulnerabilities in specific plugins and fails otherwise. As a result, a fundamental limitation for detecting a piece of malware is that malware is triggered infrequently, only showing itself when the right environment is present. We observe that, using fingerprinting techniques that capture and exploit unique properties of browser configurations, almost all existing malware can be made virtually impossible for malware scanners to detect. This paper proposes Rozzle, a JavaScript multiexecution virtual machine, as a way to explore multiple execution paths within a single execution so that environment-specific malware will reveal itself. Using large-scale experiments, we show that Rozzle increases the detection rate for offline runtime detection by almost seven times. In addition, Rozzle triples the effectiveness of online runtime detection. We show that Rozzle incurs virtually no runtime overhead and allows us to replace multiple VMs running different browser configurations with a single Rozzle-enabled browser, reducing the hardware requirements, network bandwidth, and power consumption. Index Terms—malware; cloaking; JavaScript I