The purpose of this study was to identify a correlation between the screening BI-RADS 0 (recall) rates and diagnostic BI-RADS 3 (short-interval follow-up) rates of individual interpreting radiologists, with the goal of utilizing the BI-RADS 3 rate as an acceptable performance metric in the diagnostic population. A multicenter retrospective analysis of medical audit statistics was conducted on annual radiologist performance data collected over a 14-year period in a community hospital-based practice. Mixed regression models were used to estimate the association between screening BI-RADS 0 and diagnostic BI-RADS 3 examinations while adjusting for calendar year, annual radiologist screening volume, annual radiologist diagnostic volume, and diagnostic examination indication.
View Article and Find Full Text PDFWe report superconductivity and magnetism in a new family of topological semimetals, the ternary half-Heusler compound RPdBi (R: rare earth). In this series, tuning of the rare earth f-electron component allows for simultaneous control of both lattice density via lanthanide contraction and the strength of magnetic interaction via de Gennes scaling, allowing for a unique tuning of the normal-state band inversion strength, superconducting pairing, and magnetically ordered ground states. Antiferromagnetism with ordering vector (½,½,½) occurs below a Néel temperature that scales with de Gennes factor dG, whereas a superconducting transition is simultaneously supressed with increasing dG.
View Article and Find Full Text PDFWhen electroactive nanomaterials are fully incorporated into an electrode structure, characterization of the crystallite sizes, agglomerate sizes, and dispersion of the electroactive materials can lend insight into the complex electrochemistry associated with composite electrodes. In this study, composite magnetite electrodes were sectioned using ultramicrotome techniques, which facilitated the direct observation of crystallites and agglomerates of magnetite (Fe3O4) as well as their dispersal patterns in large representative sections of electrode, via 2D cross sectional analysis by Transmission Electron Microscopy (TEM). Further, the electrochemistry of these electrodes were recorded, and Transmission X-ray Microscopy (TXM) was used to determine the distribution of oxidation states of the reduced magnetite.
View Article and Find Full Text PDFPreviously, we reported that electrodes containing silver vanadium phosphate (Ag2VO2PO4) powder exhibit a 15,000 fold increase in conductivity after discharge, concurrent with the formation of silver metal. In this study, in order to disentangle the complex nature of electrodes composed of electroactive powders, an electrochemical reduction of individual particles of Ag2VO2PO4 was conducted, to more directly probe the intrinsic materials properties of Ag2VO2PO4. Specifically, individual particle conductivity data from a nanoprobe system combined with SEM and optical imaging results revealed that the depth of discharge within an Ag2VO2PO4 particle is closely linked to the conductivity increase.
View Article and Find Full Text PDFThe functional capacity of a battery is observed to decrease, often quite dramatically, as discharge rate demands increase. These capacity losses have been attributed to limited ion access and low electrical conductivity, resulting in incomplete electrode use. A strategy to improve electronic conductivity is the design of bimetallic materials that generate a silver matrix in situ during cathode reduction.
View Article and Find Full Text PDFIn situ, in operando characterization of electrochemical cells can provide insight into the complex discharge chemistries of batteries which may not be available with destructive methods. In this study, in situ energy-dispersive X-ray spectroscopy (EDXRD) measurements are conducted for the first time on active lithium/silver vanadium diphosphate, Li/Ag2VP2O8, electrochemical cells at several depths of discharge allowing depth profiling analysis of the reduction process. This technique enables non-destructive, in operando imaging of the reduction process within a battery electrode over a millimeter scale interrogation area with micron scale resolution.
View Article and Find Full Text PDFSimultaneous low-temperature electrical resistivity and Hall effect measurements were performed on single-crystalline Bi2Se3 under applied pressures up to 50 GPa. As a function of pressure, superconductivity is observed to onset above 11 GPa with a transition temperature Tc and upper critical field Hc2 that both increase with pressure up to 30 GPa, where they reach maximum values of 7 K and 4 T, respectively. Upon further pressure increase, Tc remains anomalously constant up to the highest achieved pressure.
View Article and Find Full Text PDFTo reassess the minimum number of specimens required for an accurate diagnosis compared to the standard acquisition of five specimens. A total of 190 consecutive breast mass biopsies were performed using a 14-gauge core biopsy needle under ultrasound guidance. Two to six specimens were obtained from each mass and placed in sequential containers.
View Article and Find Full Text PDFIn the high-temperature cuprate superconductors, the pervasiveness of anomalous electronic transport properties suggests that violation of conventional Fermi liquid behavior is closely tied to superconductivity. In other classes of unconventional superconductors, atypical transport is well correlated with proximity to a quantum critical point, but the relative importance of quantum criticality in the cuprates remains uncertain. Here, we identify quantum critical scaling in the electron-doped cuprate material La(2-x)Ce(x)CuO(4) with a line of quantum critical points that surrounds the superconducting phase as a function of magnetic field and charge doping.
View Article and Find Full Text PDFWe used a scanning tunneling microscope to image the surface of SrFe(2)As(2) single crystals at 4.2 K. We found, besides the commonly reported row structures and some disordered areas, also maze-like regions.
View Article and Find Full Text PDFJ Magn Reson Imaging
November 2009
Purpose: To investigate a fast, objective, and standardized method for analyzing breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) applying principal component analysis (PCA) adjusted with a model-based method.
Materials And Methods: 3D gradient-echo DCE breast images of 31 malignant and 38 benign lesions, recorded on a 1.5T scanner, were retrospectively analyzed by PCA and by the model-based three-timepoints (3TP) method.
Objective: The goal of this study was to test the efficacy of clinical risk algorithms and a quantitative immunoturbidimetric D-dimer assay in the evaluation of patients undergoing pulmonary CT angiography for suspected acute pulmonary embolism.
Subjects And Methods: From April 1, 2007, to March 31, 2008, emergency department evaluations for clinically suspected pulmonary embolism were performed with the revised Geneva score, a quantitative D-dimer assay, and pulmonary CT angiography.
Results: Evaluations for pulmonary embolism were performed for 745 consecutively registered patients, 627 of whom were included in the study.
Introduction: Radio-frequency catheter ablation (RFCA) is an ever increasing modality for treating refractory atrial fibrillation. Radiologists should not only be able to interpret and convey anatomic variations of pulmonary veins and left atrium to referring electrophysiologists, but also should be aware of all the post-RFCA complications and their radiographic findings including this rare, but often fatal complication. This report describes a fatal atrio-esophageal fistula (AEF) involving a normal variant single left common pulmonary vein after transcatheter ablation.
View Article and Find Full Text PDFBackground: Tumor perfusion through the microvascular network can be imaged noninvasively by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). The objective of the current study was to quantify the microvascular perfusion parameters in various human breast lesions and to determine whether they varied between benign lesions and malignancy and whether they were altered with increased invasiveness.
Methods: Perfusion parameters in 22 benign fibrocystic changes, 15 ductal carcinomas in situ (DCIS), 30 infiltrating ductal carcinomas (IDC), and 22 fibroadenomas were measured using high-resolution DCE-MRI.
Objective: The purpose of this prospective study was to assess the accuracy of an add-on stereotactic unit for core needle biopsy of mammographic lesions. SUBJECTS AND METHODS. Between September 1994 and February 2001, 506 stereotactic core needle biopsies of mammographic lesions in 492 patients were performed in our center on a mammography unit with add-on stereotactic equipment.
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