‘Do you see what I see?’ Medical imaging: the interpretation of visual information

Röntgen's discovery of x-rays in 1895, gave to medicine the extraordinary benefit of being able to see inside the living body without surgery. Over time, technology has added to the sophistication of imaging processes in medicine and we now have a wide range of techniques at our disposal for the investigation and early detection of disease. But radiology deals with visual information; and like any information this requires interpretation. It is a practical field and medical images are used to make inferences about the state of peoples' health. These inferences are subject to the same variability and error as any decision-making process and so the criteria for the success of medical imaging are based not entirely on the images themselves but on the performance of the decision-makers. Research in the accuracy of medical imaging must draw on techniques from a wide range of disciplines including physics, psychology, computing, neuroscience and medicine in attempting to better understand the processes involved in visual decision-making in this context and to minimise diagnostic error

New Electricity: Generation, Pricing, Wheeling & Regulation

electricity--generation and regulation--Canada, electricity--generation and regulation--United State

New Electricity: Generation, Pricing, Wheeling & Regulation

electricity--generation and regulation--Canada, electricity--generation and regulation--United State

Energy in the Afermath of the 2003 Electricity Blackout - U.S. Speaker

energy--Canada, energy--United State

Detection or decision errors? Missed lung cancer from the posteroanterior chest radiograph

A test bank of verified chest radiographs was compiled for visual search experiments to investigate radiology performance in the detection of early lung cancer. A measure of the physical characteristics of the lesions was derived to determine the conspicuity (x) of the nodules and to investigate possible causes of failed detection. Observer performance was measured by alternate free response operating characteristic (AFROC) methodology and was supplemented with visual search recording. Correlation of AFROC scores and the x values was poor but inspection of the visual search recordings showed that most nodules were fixated. Fixations on missed lesions produced average dwell times greater than three times the minimum duration thought to be associated with detection. We conclude that the majority of errors were failures of decision rather than detection and comment on the implications of this for strategies to improve diagnostic effectiveness

Coupling of Smoothened to inhibitory G proteins reduces voltage-gated K

SMO (Smoothened), the central transducer of Hedgehog signaling, is coupled to heterotrimeric Gi proteins in many cell types, including cardiomyocytes. In this study, we report that activation of SMO with SHH (Sonic Hedgehog) or a small agonist, purmorphamine, rapidly causes a prolongation of the action potential duration that is sensitive to a SMO inhibitor. In contrast, neither of the SMO agonists prolonged the action potential in cardiomyocytes from transgenic GiCT/TTA mice, in which Gi signaling is impaired, suggesting that the effect of SMO is mediated by Gi proteins. Investigation of the mechanism underlying the change in action potential kinetics revealed that activation of SMO selectively reduces outward voltage-gated K+ repolarizing (Kv) currents in isolated cardiomyocytes and that it induces a down-regulation of membrane levels of Kv4.3 in cardiomyocytes and intact hearts from WT but not from GiCT/TTA mice. Moreover, perfusion of intact hearts with Shh or purmorphamine increased the ventricular repolarization time (QT interval) and induced ventricular arrhythmias. Our data constitute the first report that acute, noncanonical Hh signaling mediated by Gi proteins regulates K+ currents density in cardiomyocytes and sensitizes the heart to the development of ventricular arrhythmias. © 2018 Cheng et al

Implication of the first decision on visual information-sampling in the spatial frequency domain in pulmonary nodule recognition

Aim: To investigate the impact on visual sampling strategy and pulmonary nodule recognition of image-based properties of background locations in dwelled regions where the first overt decision was made. Background: Recent studies in mammography show that the first overt decision (TP or FP) has an influence on further image reading including the correctness of the following decisions. Furthermore, the correlation between the spatial frequency properties of the local background following decision sites and the first decision correctness has been reported. Methods: Subjects with different radiological experience were eye tracked during detection of pulmonary nodules from PA chest radiographs. Number of outcomes and the overall quality of performance are analysed in terms of the cases where correct or incorrect decisions were made. JAFROC methodology is applied. The spatial frequency properties of selected local backgrounds related to a certain decisions were studied. ANOVA was used to compare the logarithmic values of energy carried by non redundant stationary wavelet packet coefficients. Results: A strong correlation has been found between the number of TP as a first decision and the JAFROC score (r = 0.74). The number of FP as a first decision was found negatively correlated with JAFROC (r = -0.75). Moreover, the differential spatial frequency profiles outcomes depend on the first choice correctness

A variant in LIN28B is associated with 2D:4D finger-length ratio, a putative retrospective biomarker of prenatal testosterone exposure

The ratio of the lengths of an individual's second to fourth digit (2D:4D) is commonly used as a noninvasive retrospective biomarker for prenatal androgen exposure. In order to identify the genetic determinants of 2D:4D, we applied a genome-wide association approach to 1507 11-year-old children from the Avon Longitudinal Study of Parents and Children (ALSPAC) in whom 2D:4D ratio had been measured, as well as a sample of 1382 12- to 16-year-olds from the Brisbane Adolescent Twin Study. A meta-analysis of the two scans identified a single variant in the LIN28B gene that was strongly associated with 2D:4D (rs314277: p = 4.1 108) and was subsequently independently replicated in an additional 3659 children from the ALSPAC cohort (p = 1.53 106). The minor allele of the rs314277 variant has previously been linked to increased height and delayed age at menarche, but in our study it was associated with increased 2D:4D in the direction opposite to that of previous reports on the correlation between 2D:4D and age at menarche. Our findings call into question the validity of 2D:4D as a simplistic retrospective biomarker for prenatal testosterone exposure