Endoscopic ultrasound (EUS) elastography represents a new imaging procedure that might characterize the differences of hardness and strain between diseased tissue and normal tissue. The aim of this ...study was to assess the efficiency of EUS elastography for the differentiation of focal masses in chronic pancreatitis and pancreatic cancer.
The study group comprised 258 patients with focal pancreatic masses included prospectively at 13 participating centers. Qualitative analysis of the diagnoses made by two expert doctors using all recorded video clips was performed in order to test the interobserver variability. A post-processing software analysis was used to examine the EUS elastography videos by calculating average-hue histograms of individual elastography images. The quantitative information was used to calculate intra-observer variability and the accuracy of the method.
Qualitative analysis of the recorded videos revealed a kappa value of 0.72. Intra-observer variability analysis revealed that the single measure intraclass correlation ranged between 0.86 and 0.94. The average-hue histogram analysis of the data indicated a sensitivity of 93.4 %, a specificity of 66.0 %, a positive predictive value of 92.5 %, a negative predictive value of 68.9 %, and an overall accuracy of 85.4 %, based on a cut-off value of 175. Area under the receiver operating characteristic curve (AUROC) was 0.854 ( P < 0.0001) with a confidence interval of 0.804 - 0.894.
The value of quantitative analysis of EUS elastography recordings was proven by good reproducibility of the videos, as well as good parameters of the AUROC analysis. (Clinical Trials.gov identifier: CT00909103).
The technical part of these Guidelines and Recommendations, produced under the auspices of EFSUMB, provides an introduction to the physical principles and technology on which all forms of current ...commercially available ultrasound elastography are based. A difference in shear modulus is the common underlying physical mechanism that provides tissue contrast in all elastograms. The relationship between the alternative technologies is considered in terms of the method used to take advantage of this. The practical advantages and disadvantages associated with each of the techniques are described, and guidance is provided on optimisation of scanning technique, image display, image interpretation and some of the known image artefacts.
Second-generation intravenous blood-pool ultrasound contrast agents are increasingly used in endoscopic ultrasound (EUS) for characterization of microvascularization, differential diagnosis of benign ...and malignant focal lesions, and improving staging and guidance of therapeutic procedures. Although initially used as Doppler signal enhancers, second-generation microbubble contrast agents are now used with specific contrast harmonic imaging techniques, which benefit from the highly nonlinear behavior of the microbubbles. Contrast-specific modes based on multi-pulse technology are used to perform contrast-enhanced harmonic EUS based on a very low mechanical index (0.08 - 0.12). Quantification techniques based on dynamic contrast-enhanced ultrasound have been recommended for perfusion imaging and monitoring of anti-angiogenic treatment, mainly based on time-intensity curve analysis. Most of the clinical applications include the differential diagnosis of focal pancreatic masses, with adenocarcinoma having a distinct hypovascular (hypo-enhanced) appearance compared with neuroendocrine tumors, which are hypervascular (with strong arterial hyper-enhancement). However, pseudotumoral chronic pancreatitis and autoimmune pancreatitis also have an iso- or hypervascular appearance, making the differential diagnosis difficult. Even more promising is the use of dynamic contrast-enhanced harmonic EUS for the longitudinal monitoring of the effects of chemotherapy and/or anti-angiogenic therapy in advanced digestive cancers, which are difficult to examine by conventional cross-sectional imaging techniques.
Purpose
Accurate staging of colonic cancer is important for patient stratification. We aimed to correlate the diagnostic accuracy of preoperative computed tomography (CT) with final histopathology as ...reference standard.
Methods
Data was collected retrospectively on 615 consecutive patients operated for colonic cancer. Evaluation was based upon T-stage. Patients were stratified into high-risk and low-risk groups, based on the extent of tumor invasion beyond the proper muscle layer of more or less than 5 mm. The Kendall tau correlation coefficient was used to calculate concordance between radiological (r)T-stage obtained at CT imaging and pathological (p)T-stage from the final pathology.
Results
In total, 501 patients were included. We found no significant differences in the Kendall tau values for diagnostic measures between the groups at the 95% confidence interval (CI) level: 49% (95% CI, 43–55) for all individuals, 48% (95% CI, 40–56) for screened individuals, and 47% (95% CI, 37-56) for non-screened individuals. The overall sensitivity and specificity for all individuals in identifying high-risk tumors on CT was 65% (95% CI, 56–73) and 89% (95% CI, 85–92). The risk of ending up in the high-risk group due to overstaging among all individuals was calculated as the number needed to harm 11.7 (95% CI, 9–16).
Conclusions
There is basis for improvement of CT-based preoperative staging of patients with colorectal cancer. Supplementary modalities may be needed for correct staging of patients preoperatively, especially in relation to stratification of patients into neoadjuvant treatments or tailored therapy in patients with early cancers.
Angiogenesis is a crucial event for tumor growth and it is regulated predominantly by several different growth factors. Vascular endothelial growth factor protein family (VEGF) and its receptors are ...probably the most important tissue factors responsible for angioblast differentiation and tube formation. VEGF protein family currently comprises several members: VEGF (or VEGF-A), VEGF-B, VEGF-C and VEGF-D, VEGF-F, placental growth factor (PlGF), and their receptors VEGFR-1, VEGFR-2 and VEGFR-3. VEGF is a key angiogenic growth factor and its level of expression is a critical marker for detection of the angiogenic diseases. The potent role of VEGF in tumor angiogenesis has been widely described in the past decade, being expressed in most types of nondigestive and digestive cancers. VEGF family members play an important role in the development of pancreatic cancer (especially VEGF-A, VEGF-C, VEGF-D, VEGFR-1 and VEGFR-2). VEGF-A is the most specific and prominent angiogenic factor among all family members and VEGFR-2 is the most important receptor in evaluating the angiogenesis in pancreatic cancer. Thus, VEGF overexpression may be considered as a diagnostic marker and as a poor prognostic factor of the disease.
LOPES, the LOFAR prototype station, was an antenna array for cosmic-ray air showers operating from 2003 to 2013 within the KASCADE-Grande experiment. Meanwhile, the analysis is finished and the data ...of air-shower events measured by LOPES are available with open access in the KASCADE Cosmic Ray Data Center (KCDC). This article intends to provide a summary of the achievements, results, and lessons learned from LOPES. By digital, interferometric beamforming the detection of air showers became possible in the radio-loud environment of the Karlsruhe Institute of Technology (KIT). As a prototype experiment, LOPES tested several antenna types, array configurations and calibration techniques, and pioneered analysis methods for the reconstruction of the most important shower parameters, i.e., the arrival direction, the energy, and mass-dependent observables such as the position of the shower maximum. In addition to a review and update of previously published results, we also present new results based on end-to-end simulations including all known instrumental properties. For this, we applied the detector response to radio signals simulated with the CoREAS extension of CORSIKA, and analyzed them in the same way as measured data. Thus, we were able to study the detector performance more accurately than before, including some previously inaccessible features such as the impact of noise on the interferometric cross-correlation beam. These results led to several improvements, which are documented in this paper and can provide useful input for the design of future cosmic-ray experiments based on the digital radio-detection technique.
The fourth part of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines on Interventional Ultrasound describes general aspects of endoscopic ...ultrasound-guided diagnostic and therapeutic interventions and assesses the evidence for endoscopic ultrasound-guided sampling. Endoscopic ultrasound combines the most advanced high-resolution ultrasound imaging of lesions within the wall and in the vicinity of the gastrointestinal tract and safe and effective fine needle based tissue acquisition from these lesions. The guideline addresses the indications, contraindications, techniques, adverse events, training and clinical impact of EUS-guided sampling. Advantages and drawbacks are weighed in comparison with image-guided percutaneous biopsy. Based on the most current evidence, clinical practice recommendations are given for crucial preconditions and steps of EUS-guided sampling as well as for safe performance. Additionally, the guideline deals with the principles and reliability of cytopathological reporting in endoscopic ultrasound-guided sampling (long version).
Emission of electromagnetic waves from high energy particle showers is a powerful tool that can be used to detect the most elusive cosmic neutrinos of astrophysical or cosmogenic origin. We present ...here simulations of showers with a primary energy in the range 1018−1021 eV initiated by νe, νμ and ντ neutrinos. A medium that is both dense and transparent in the low radio frequencies part of the electromagnetic spectrum, like rock salt, is used as active medium where the shower develops. The calculation of the radio signal was performed by approximating the shower with a current density using the longitudinal profile of the charge excess, for estimation at low frequencies, below 500 MHz.
The aim of this work is to give estimates of the amplitude of the signal induced by νe, νμ and ντ neutrinos.
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