Search

Pleural effusions are categorized as transudative or exudative, with transudative effusions usually reflecting the sequala of a systemic etiology and exudative effusions usually resulting from a process localized to the pleura. Common causes of transudative pleural effusions include congestive heart failure, cirrhosis, and renal failure, whereas exudative effusions are typically due to infection, malignancy, or autoimmune disorders. This document summarizes appropriateness guidelines for imaging in four common clinical scenarios in patients with known or suspected pleural effusion or pleural disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation., (Copyright © 2024 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Self-monitoring is essential for effectively regulating learning, but difficult in visual diagnostic tasks such as radiograph interpretation. Eye-tracking technology can visualize viewing behavior in gaze displays, thereby providing information about visual search and decision-making. We hypothesized that individually adaptive gaze-display feedback improves posttest performance and self-monitoring of medical students who learn to detect nodules in radiographs. We investigated the effects of: (1) Search displays, showing which part of the image was searched by the participant; and (2) Decision displays, showing which parts of the image received prolonged attention in 78 medical students. After a pretest and instruction, participants practiced identifying nodules in 16 cases under search-display, decision-display, or no feedback conditions (n = 26 per condition). A 10-case posttest, without feedback, was administered to assess learning outcomes. After each case, participants provided self-monitoring and confidence judgments. Afterward, participants reported on self-efficacy, perceived competence, feedback use, and perceived usefulness of the feedback. Bayesian analyses showed no benefits of gaze displays for post-test performance, monitoring accuracy (absolute difference between participants' estimated and their actual test performance), completeness of viewing behavior, self-efficacy, and perceived competence. Participants receiving search-displays reported greater feedback utilization than participants receiving decision-displays, and also found the feedback more useful when the gaze data displayed was precise and accurate. As the completeness of search was not related to posttest performance, search displays might not have been sufficiently informative to improve self-monitoring. Information from decision displays was rarely used to inform self-monitoring. Further research should address if and when gaze displays can support learning., (© 2024. The Author(s).)

While radiological imaging is presented as two-dimensional images either on radiography or cross-sectional imaging, it is important for interpreters to understand three-dimensional anatomy and pathology. We hypothesized that virtual reality (VR) may serve as an engaging and effective way for trainees to learn to extrapolate from two-dimensional images to an understanding of these three-dimensional structures. We created a Google Cardboard Virtual Reality application that depicts intracranial vasculature and aneurysms. We then recruited 12 medical students to voluntarily participate in our study. The performance of the students in identifying intracranial aneurysms before and after the virtual reality training was evaluated and compared to a control group. While the experimental group's performance in correctly identifying aneurysms after virtual reality educational intervention was better than the control's (experimental increased by 5.3%, control decreased by 2.1%), the difference was not statistically significant (p-value of 0.06). Significantly, survey data from the medical students was very positive with students noting they preferred the immersive virtual reality training over conventional education and believed that VR would be a helpful educational tool for them in the future. We believe virtual reality can serve as an important tool to help radiology trainees better understand three-dimensional anatomy and pathology., (© 2023. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

Purpose: Diagnostic errors are common in radiology. The gestalt impression of an image refers to the rapid holistic understanding one formulates about an image and may facilitate improved diagnostic accuracy. The ability to generate a gestalt impression is typically acquired over time and is generally not explicitly taught. Our study aims to assess whether perceptual training using second look and minification technique (SLMT) can help image interpreters formulate a holistic understanding of an image and become more accurate at evaluating medical images., Approach: Fourteen healthcare trainees voluntarily participated in a perceptual training module, comparing the differences in detection of nodules and other actionable finding (OAF) on chest radiographs before and after perceptual training intervention. The experimental group received SLMT training, and the control group did not., Results: Survey results were positive for all items, with the p -values < 0.01 . There was improvement in the performance in detection of nodules and OAF in both groups. However, this change was statistically significant only for OAFs in the control group ( p -value < 0.05 ) but not the experimental group., Conclusions: SLMT training was viewed by participants as an extremely helpful educational tool. Survey results indicated that participants felt the SLMT was a beneficial educational intervention. The experimental group's detection of nodules and OAF improved after SLMT, though not statistically significantly so, which may be related to the small sample size or lack of training effect. Perceptual training using SLMT may help as a useful educational technique, help radiologists identify abnormalities, and improve workflow., (© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE).)

Purpose: Perceptual errors account for a significant percent of errors in radiology. Reasons for failure to identify significant lesions are partially due to suboptimal differences in image contrast. The goal of this study is to determine if teaching trainees how to adjust image contrast, window, and level helps trainees identify pulmonary nodules on chest radiographs (CXRs)., Approach: Fourteen medical students voluntarily participated. Subjects were asked to identify pulmonary nodules on CXRs before and after being taught how to adjust image contrast, window, and level. At the end of the study, subjects were given a survey assessing their perceptions about their training., Results: The experimental group was more confident in their ability to localize nodules relative to the control group ( P -value = 0.003). Subjects demonstrated statistically significant improvement in their ability to identify and localize nodules, with the experimental group performing better than the control group, though there was no statistically significant difference between groups. Participant survey indicated that they felt this training was beneficial, P -values for all survey responses were significant ( P -values all < 0.02 )., Conclusions: Teaching subjects how to window and level medical images may be a useful adjunct to current training for medical image interpretation., (© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE).)

We describe the curation, annotation methodology, and characteristics of the dataset used in an artificial intelligence challenge for detection and localization of COVID-19 on chest radiographs. The chest radiographs were annotated by an international group of radiologists into four mutually exclusive categories, including "typical," "indeterminate," and "atypical appearance" for COVID-19, or "negative for pneumonia," adapted from previously published guidelines, and bounding boxes were placed on airspace opacities. This dataset and respective annotations are available to researchers for academic and noncommercial use., (© 2022. The Author(s) under exclusive licence to Society for Imaging Informatics in Medicine.)

Purpose: Gamification is used in several fields as an adjunct to standard educational methods but has found limited application in radiology to date. Gamification may be useful for teaching radiology skills typically acquired through experience, such as perceptual skills. The goal of our study is to use a gamified radiology workstation to teach skills related to identification of pulmonary nodules and evaluate for changes in trainee performance., Approach: We constructed a game called RADHunters to teach perceptual skills related to identification of pulmonary nodules on chest radiographs. Control and experimental groups were tasked with identifying nodules on chest radiographs on two sets of cases. The experimental group received gamified training for nodule identification using RADHunters between case sets, while the control group did not. Performance at nodule identification, localization, and confidence were compared. A poststudy survey was administered to assess for participants' thoughts about the gamified nodule detection training., Results: Survey responses were very positive with p -values for all survey responses < 0.001 , indicating subjects felt this training was beneficial. Experimental and control groups had a statistically significant improvement in their ability to identify and localize nodules with p -values < 0.05 . There was no significant difference between control and experimental groups. Neither group showed a statistically significant increase in their confidence in nodule localization., Conclusions: Perceptual training using gamification may be a useful adjunct to conventional methods of radiology education., (© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE).)

Diffuse lung diseases are a heterogeneous group of disorders that can be difficult to differentiate by imaging using traditional methods of evaluation. The overlap between various disorders results in difficulty when medical professionals attempt to interpret images. Artificial intelligence offers new tools for the evaluation and quantification of imaging of patients with diffuse lung disease., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: This retrospective review examines the incidence of pulmonary embolism (PE) during computed tomography pulmonary angiography (CTPA) exams performed in the emergency room setting of a tertiary care center over dominant periods of the ancestral, Delta, and Omicron variants of COVID-19., Materials/methods: Demographic information, patient comorbidities and risk factors, vaccination status, and COVID-19 infection status were collected from patient's charts. Incidence of PE in COVID positive patients was compared between variant waves. Subgroup analysis of vaccination effect was performed., Results: CTPA was ordered in 18.3% of COVID-19 positive patients during the ancestral variant period, 18.3% during the Delta period and 17.3% during the Omicron wave. PE was seen in 15.0% of the ancestral COVID-19 variant cohort, 10.6% in the Delta COVID cohort and 9.23% of the Omicron cohort, reflecting a 41% and 60% increased risk of PE with ancestral variants compared to Delta and Omicron periods respectively. The study however was underpowered and the difference in rate of PE did not reach statistically significance (p = 0.43 and p = 0.22). Unvaccinated patients had an 2.75-fold increased risk of COVID-associated PE during the Delta and Omicron periods (p = .02) compared to vaccinated or recovered patients., Conclusion: Vaccination reduces the risk of COVID-19 associated PE. Patients infected with the Delta and Omicron COVID-19 variants may have a lower incidence of pulmonary embolism, though a larger or multi-institution study is needed to prove definitively., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Deep learning has shown recent success in classifying anomalies in chest x-rays, but datasets are still small compared to natural image datasets. Supervision of abnormality localization has been shown to improve trained models, partially compensating for dataset sizes. However, explicitly labeling these anomalies requires an expert and is very time-consuming. We propose a potentially scalable method for collecting implicit localization data using an eye tracker to capture gaze locations and a microphone to capture a dictation of a report, imitating the setup of a reading room. The resulting REFLACX (Reports and Eye-Tracking Data for Localization of Abnormalities in Chest X-rays) dataset was labeled across five radiologists and contains 3,032 synchronized sets of eye-tracking data and timestamped report transcriptions for 2,616 chest x-rays from the MIMIC-CXR dataset. We also provide auxiliary annotations, including bounding boxes around lungs and heart and validation labels consisting of ellipses localizing abnormalities and image-level labels. Furthermore, a small subset of the data contains readings from all radiologists, allowing for the calculation of inter-rater scores., (© 2022. The Author(s).)

Artificial intelligence (AI) systems play an increasingly important role in all parts of the imaging chain, from image creation to image interpretation to report generation. In order to responsibly manage radiology AI systems and make informed purchase decisions about them, radiologists must understand the underlying principles of AI. Our task force was formed by the Radiology Research Alliance (RRA) of the Association of University Radiologists to identify and summarize a curated list of current educational materials available for radiologists., (Copyright © 2021. Published by Elsevier Inc.)

Recent studies have demonstrated the effectiveness of simulation in radiology perceptual education. While current software exists for perceptual research, these software packages are not optimized for inclusion of educational materials and do not have full integration for presentation of educational materials. To address this need, we created a user-friendly software application, RadSimPE. RadSimPE simulates a radiology workstation, displays radiology cases for quantitative assessment, and incorporates educational materials in one seamless software package. RadSimPE provides simple customizability for a variety of educational scenarios and saves results to quantitatively document changes in performance. We performed two perceptual education studies involving evaluation of central venous catheters: one using RadSimPE and the second using conventional software. Subjects in each study were divided into control and experimental groups. Performance before and after perceptual education was compared. Improved ability to classify a catheter as adequately positioned was demonstrated only in the RadSimPE experimental group. Additional quantitative performance metrics were similar for both the group using conventional software and the group using RadSimPE. The study proctors felt that it was qualitatively easier to run the RadSimPE session due to integration of educational material into the simulation software. In summary, we created a user-friendly and customizable simulated radiology workstation software package for perceptual education. Our pilot test using the software for central venous catheter assessment was a success and demonstrated effectiveness of our software in improving trainee performance., (© 2021. Society for Imaging Informatics in Medicine.)

Purpose: Experienced radiologists have enhanced global processing ability relative to novices, allowing experts to rapidly detect medical abnormalities without performing an exhaustive search. However, evidence for global processing models is primarily limited to two-dimensional image interpretation, and it is unclear whether these findings generalize to volumetric images, which are widely used in clinical practice. We examined whether radiologists searching volumetric images use methods consistent with global processing models of expertise. In addition, we investigated whether search strategy (scanning/drilling) differs with experience level. Approach: Fifty radiologists with a wide range of experience evaluated chest computed-tomography scans for lung nodules while their eye movements and scrolling behaviors were tracked. Multiple linear regressions were used to determine: (1) how search behaviors differed with years of experience and the number of chest CTs evaluated per week and (2) which search behaviors predicted better performance. Results: Contrary to global processing models based on 2D images, experience was unrelated to measures of global processing (saccadic amplitude, coverage, time to first fixation, search time, and depth passes) in this task. Drilling behavior was associated with better accuracy than scanning behavior when controlling for observer experience. Greater image coverage was a strong predictor of task accuracy. Conclusions: Global processing ability may play a relatively small role in volumetric image interpretation, where global scene statistics are not available to radiologists in a single glance. Rather, in volumetric images, it may be more important to engage in search strategies that support a more thorough search of the image., (© 2021 Society of Photo-Optical Instrumentation Engineers (SPIE).)

A substantial number of medical errors in radiology are attributed to failures of perception or decision making, although it is believed that experience (or expertise) might buffer diagnosticians from some types of perceptual-cognitive bias. We examined how the quality of contextual information influences decision making and how underlying perceptual-cognitive processes change as a function of experience and diagnostic accuracy. Twenty-one radiologists dictated their findings on 16 deidentified musculoskeletal radiographic cases while wearing a mobile-eye tracking system. Patient histories were mismatched on a subset of cases to be miscued relative to the correct diagnosis. Experienced radiologists outperformed less-experienced participants, but no systematic differences in gaze behaviors emerged between groups. Miscued case notes increased perceptual-cognitive bias in both groups, resulting in an approximate 40% decrease in diagnostic accuracy. Most errors were judgment errors, meaning participants visually fixated on the abnormality for longer than a second yet still failed to make the correct diagnosis. Findings suggest a physician's confidence in their diagnosis might be misplaced after spending insufficient time extracting relevant information from key areas of the visual display, or when decisions are based primarily on a priori expectations derived from patient histories. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Prior research has demonstrated that perceptual training can improve the ability of healthcare trainees in identifying abnormalities on medical images, but it is unclear if the improved performance is due to learning or attentional shift-the diversion of perceptional resources away from other activities to a specified task. Our objective is to determine if research subject performance in perceiving the central venous catheter position on radiographs is improved after perceptional training and if improved performance is due to learning or an attentional shift. Forty-one physician assistant students were educated on the appropriate radiographic position of central venous catheters and then asked to evaluate the catheter position in two sets of radiographic cases. The experimental group was provided perceptional training between case sets one and two. The control group was not. Participants were asked to characterize central venous catheters for appropriate positioning (task of interest) and to assess radiographs for cardiomegaly (our marker for attentional shift). Our results demonstrated increased confidence in localization in the experimental group ( p -value < 0.001 ) but not in the control group ( p - value = 0.882 ). The ability of subjects to locate the catheter tip significantly improved in both control and experimental groups. Both the experimental ( p - value = 0.007 ) and control groups ( p - value = 0.001 ) demonstrated equivalent decreased performance in assessing cardiomegaly; the difference between groups was not significant ( p - value = 0.234 ). This suggests the performance improvement was secondary to learning not due to an attentional shift., (© 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).)

Guest editors provide an introduction to the Special Section on Medical Image Perception and Observer Performance., (© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE).)

Interpretation of increasingly complex imaging studies involves multiple intricate tasks requiring visual evaluation, cognitive processing, and decision-making. At each stage of this process, there are opportunities for error due to human factors including perceptual and ergonomic conditions. Investigation into the root causes of interpretive error in radiology first began over a century ago. In more recent work, there has been increasing recognition of the limits of human image perception and other human factors and greater acknowledgement of the role of the radiologist's environment in increasing the risk of error. This article reviews the state of research on perceptual and interpretive error in radiology. This article focuses on avenues for further error examination, and strategies for mitigating these errors are discussed. The relationship between artificial intelligence and interpretive error is also considered., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE. The goal of this article is to examine some of the current cardiothoracic radiology applications of artificial intelligence in general and deep learning in particular. CONCLUSION. Artificial intelligence has been used for the analysis of medical images for decades. Recent advances in computer algorithms and hardware, coupled with the availability of larger labeled datasets, have brought about rapid advances in this field. Many of the more notable recent advances have been in the artificial intelligence subfield of deep learning.

As radiology is inherently a data-driven specialty, it is especially conducive to utilizing data processing techniques. One such technique, deep learning (DL), has become a remarkably powerful tool for image processing in recent years. In this work, the Association of University Radiologists Radiology Research Alliance Task Force on Deep Learning provides an overview of DL for the radiologist. This article aims to present an overview of DL in a manner that is understandable to radiologists; to examine past, present, and future applications; as well as to evaluate how radiologists may benefit from this remarkable new tool. We describe several areas within radiology in which DL techniques are having the most significant impact: lesion or disease detection, classification, quantification, and segmentation. The legal and ethical hurdles to implementation are also discussed. By taking advantage of this powerful tool, radiologists can become increasingly more accurate in their interpretations with fewer errors and spend more time to focus on patient care., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

To more accurately trigger data acquisition and reduce radiation exposure of coronary computed tomography angiography (CCTA), a multimodal framework utilizing both electrocardiography (ECG) and seismocardiography (SCG) for CCTA prospective gating is presented. Relying upon a three-layer artificial neural network that adaptively fuses individual ECG- and SCG-based quiescence predictions on a beat-by-beat basis, this framework yields a personalized quiescence prediction for each cardiac cycle. This framework was tested on seven healthy subjects (age: 22-48; m/f: 4/3) and eleven cardiac patients (age: 31-78; m/f: 6/5). Seventeen out of 18 benefited from the fusion-based prediction as compared to the ECG-only-based prediction, the traditional prospective gating method. Only one patient whose SCG was compromised by noise was more suitable for ECG-only-based prediction. On average, our fused ECG-SCG-based method improves cardiac quiescence prediction by 47% over ECG-only-based method; with both compared against the gold standard, B-mode echocardiography. Fusion-based prediction is also more resistant to heart rate variability than ECG-only- or SCG-only-based prediction. To assess the clinical value, the diagnostic quality of the CCTA reconstructed volumes from the quiescence derived from ECG-, SCG- and fusion-based predictions were graded by a board-certified radiologist using a Likert response format. Grading results indicated the fusion-based prediction improved diagnostic quality. ECG may be a sub-optimal modality for quiescence prediction and can be enhanced by the multimodal framework. The combination of ECG and SCG signals for quiescence prediction bears promise for a more personalized and reliable approach than ECG-only-based method to predict cardiac quiescence for prospective CCTA gating.

The goal of this research was to examine whether search pattern training for central line positioning on chest radiographs (CXRs) improves the ability of healthcare trainees and practitioners to identify malpositioned central venous catheters. Two sets of CXRs with central catheters were shown; half of the images contained catheters that were appropriately positioned, half that were malpositioned. Subjects were asked to: mark the tip of the catheter using the simulated radiology workstations, indicate their confidence in tip localization, and state whether the catheter was appropriately positioned or malpositioned. Subjects were also given a survey assessing their thoughts about the usefulness of search pattern training and the simulated radiology workstation. There was a significant improvement in subjects' ability to classify a catheter as malpositioned after training, [Formula: see text]-value = 0.03. There was no significant difference in localization of the catheter tips or in the confidence for tip localization. Subjects' responses to the questionnaire were significantly positive for all statements, indicating that they felt search pattern training using a simulated radiology workstation had a positive impact on their education. These results suggest that our knowledge of medical image perception may be useful for developing rational educational tools for image interpretation, and that simulated radiology workstations may be a helpful means of deploying these tools.

Background: Our health system orders a high number of STAT priority portable chest radiographs (62%) compared to Routine (35%) and Today (3%). Retrospective chart review of 1000 chest radiographs ordered with the STAT priority revealed that 38% of studies did not indicate clinical urgency. Given the high number or STAT priority portable chest radiographs ordered, prioritizing acquisition and interpretation of true STATs has become challenging for technologists and radiologists, leading to process inefficiencies, long turnaround times (TATs), communication failures, and patient-safety errors., Methods: A multidisciplinary team analyzed the current pathway for exam order to finalized report, identified failure modes of imaging order to completion process, and developed guidelines for what constitutes a true STAT examination. A new "urgent" order category meeting the definition of true STAT was designed, tested, and implemented over a 9-month period in participating intensive care units RESULTS: Since study implementation, 108 "urgent" examinations were ordered. Median TAT for a STAT examination from order entry to image acquisition dropped from 70 minutes preimplementation to 16 minutes for "urgent" examinations. Median TAT for exam completion to radiologist image interpretation dropped from 520 minutes preimplementation to 14 minutes for "urgent" examinations. Since implementation, "urgent" examinations were found to be more concordant (70%) with the status of a critically ill patient than STAT examinations (62%)., Conclusions: The complexity of large multispecialty medical centers and lack of direct interaction of the radiologist with clinicians has led to underappreciation of the needs of ordering providers by radiology, and elucidated system limitations of radiology by ordering providers. By involving a team of frontline clinicians, our team standardized the process of identifying, ordering, procuring, interpreting, and communicating results of true STAT examinations. The process created by our team now serves as a template for implementation in other locations and service lines of our hospital., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Cardiac computed tomography (CT) angiography using prospective gating requires that data be acquired during intervals of minimal cardiac motion to obtain diagnostic images of the coronary vessels free of motion artifacts. This work is intended to assess B-mode echocardiography as a continuous-time indication of these quiescent periods to determine if echocardiography can be used as a cost-efficient, non-ionizing modality to develop new prospective gating techniques for cardiac CT. These new prospective gating approaches will not be based on echocardiography itself but on CT-compatible modalities derived from the mechanics of the heart (e.g. seismocardiography and impedance cardiography), unlike the current standard electrocardiogram. To this end, echocardiography and retrospectively-gated CT data were obtained from ten patients with varied cardiac conditions. CT reconstructions were made throughout the cardiac cycle. Motion of the interventricular septum (IVS) was calculated from both echocardiography and CT reconstructions using correlation-based, deviation techniques. The IVS was chosen because it (1) is visible in echocardiography images, whereas the coronary vessels generally are not, and (2) has been shown to be a suitable indicator of cardiac quiescence. Quiescent phases were calculated as the minima of IVS motion and CT volumes were reconstructed for these phases. The diagnostic quality of the CT reconstructions from phases calculated from echocardiography and CT data was graded on a four-point Likert scale by a board-certified radiologist fellowship-trained in cardiothoracic radiology. Using a Wilcoxon signed-rank test, no significant difference in the diagnostic quality of the coronary vessels was found between CT volumes reconstructed from echocardiography- and CT-selected phases. Additionally, there was a correlation of 0.956 between the echocardiography- and CT-selected phases. This initial work suggests that B-mode echocardiography can be used as a tool to develop CT-compatible gating techniques based on modalities derived from cardiac mechanics rather than relying on the ECG alone.

The goal of this research is to demonstrate that teaching healthcare trainees a formal search or scan pattern for evaluation of the lungs improves their ability to identify pulmonary nodules on chest radiographs (CXRs). A group of physician assistant trainees were randomly assigned to control and experimental groups. Each group was shown two sets of CXRs, each set with a nodule prevalence of approximately 50%. The experimental group received search pattern training between case sets, whereas the control group did not. Both groups were asked to mark nodules when present and indicate their diagnostic confidence. Subject performance at nodule detection was quantified using changes in area under the localization receiver operating characteristic curve ([Formula: see text]). There was no significant improvement in performance between case sets for the control group. There was a significant improvement in subject performance after training for the experimental group, [Formula: see text], [Formula: see text]. These results demonstrate that teaching a search pattern to trainees improves their ability to identify nodules and decreases the number of perceptual errors in nodule identification, and suggest that our knowledge of medical image perception may be used to develop rational tools for the education of healthcare trainees.

A 68-year-old man was referred to the pulmonary clinic for evaluation of cough and a 5-cm right upper lobe mass. He was in his usual state of health until 1 year prior when he developed intermittent cough, wheezing, and sinus congestion. He denied any sputum production or hemoptysis. He also denied any fevers, chills, or weight loss. He had received various treatments within the prior 6 months, including short courses of oral prednisone, levofloxacin, and bronchodilators, without any relief of his symptoms.

Purpose: Simulation has been used as an educational and assessment tool in several fields, generally involving training of physical skills. To date, simulation has found limited application in teaching and assessment of skills related to image perception and interpretation. The goal of this pilot study was to evaluate the feasibility of simulation as a tool for teaching and assessment of skills related to perception of nodules on chest radiography., Methods: This study received an exemption from the institutional review board. Subjects consisted of nonradiology health care trainees. Subjects underwent training and assessment of pulmonary nodule identification skills on chest radiographs at simulated radiology workstations. Subject performance was quantified by changes in area under the localization receiver operating characteristic curve. At the conclusion of the study, all subjects were given a questionnaire with five questions comparing learning at a simulated workstation with training using conventional materials. Statistical significance for questionnaire responses was tested using the Wilcoxon signed rank test., Results: Subjects demonstrated statistically significant improvement in nodule identification after training at a simulated radiology workstation (change in area under the curve, 0.1079; P = .015). Subjects indicated that training on simulated radiology workstations was preferable to conventional training methods for all questions; P values for all questions were less than .01., Conclusions: Simulation may be a useful tool for teaching and assessment of skills related to medical image perception and interpretation. Further study is needed to determine which skills and trainee populations may be most amenable to training and assessment using simulation., (Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.)

Simulation is a promising method for improving clinician performance, enhancing team training, increasing patient safety, and preventing errors. Training scenarios to enrich medical student and resident education, and apply toward competency assessment, recertification, and credentialing are important applications of simulation in radiology. This review will describe simulation training for procedural skills, interpretive and noninterpretive skills, team-based training and crisis management, professionalism and communication skills, as well as hybrid and in situ applications of simulation training. A brief overview of current simulation equipment and software and the barriers and strategies for implementation are described. Finally, methods of measuring competency and assessment are described, so that the interested reader can successfully implement simulation training into their practice., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: The altered PI3K/mTOR pathway is implicated in lung cancer, but mTOR inhibitors have failed to demonstrate efficacy in advanced lung cancer. We studied the pharmacodynamic effects of everolimus in resectable non-small cell lung cancer (NSCLC) to inform further development of these agents in lung cancer., Experimental Design: We enrolled 33 patients and obtained baseline tumor biopsy and 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) imaging followed by everolimus treatment (5 or 10 mg daily, up to 28 days), or without intervening treatment for controls. Target modulation by everolimus was quantified in vivo and ex vivo by comparing metabolic activity on paired PET scans and expression of active phosphorylated forms of mTOR, Akt, S6, eIF4e, p70S6K, 4EBP1, and total Bim protein between pretreatment and posttreatment tissue samples., Results: There were 23 patients on the treatment arm and 10 controls; median age 64 years; 22 tumors (67%) were adenocarcinomas. There was a dose-dependent reduction in metabolic activity (SUVmax: 29.0%, -21%, -24%; P = 0.014), tumor size (10.1%, 5.8%, -11.6%; P = 0.047), and modulation of S6 (-36.1, -13.7, -77.0; P = 0.071) and pS6 (-41.25, -61.57, -47.21; P = 0.063) in patients treated in the control, 5-mg, and 10-mg cohorts, respectively. Targeted DNA sequencing in all patients along with exome and whole transcriptome RNA-seq in an index patient with hypersensitive tumor was employed to further elucidate the mechanism of everolimus activity., Conclusions: This "window-of-opportunity" study demonstrated measurable, dose-dependent, biologic, metabolic, and antitumor activity of everolimus in early-stage NSCLC., (©2015 American Association for Cancer Research.)

Purpose: Accurate knowledge of cardiac quiescence is crucial to the performance of many cardiac imaging modalities, including computed tomography coronary angiography (CTCA). To accurately quantify quiescence, a method for detecting the quiescent periods of the heart from retrospective cardiac computed tomography (CT) using a correlation-based, phase-to-phase deviation measure was developed., Methods: Retrospective cardiac CT data were obtained from 20 patients (11 male, 9 female, 33-74 yr) and the left main, left anterior descending, left circumflex, right coronary artery (RCA), and interventricular septum (IVS) were segmented for each phase using a semiautomated technique. Cardiac motion of individual coronary vessels as well as the IVS was calculated using phase-to-phase deviation. As an easily identifiable feature, the IVS was analyzed to assess how well it predicts vessel quiescence. Finally, the diagnostic quality of the reconstructed volumes from the quiescent phases determined using the deviation measure from the vessels in aggregate and the IVS was compared to that from quiescent phases calculated by the CT scanner. Three board-certified radiologists, fellowship-trained in cardiothoracic imaging, graded the diagnostic quality of the reconstructions using a Likert response format: 1 = excellent, 2 = good, 3 = adequate, 4 = nondiagnostic., Results: Systolic and diastolic quiescent periods were identified for each subject from the vessel motion calculated using the phase-to-phase deviation measure. The motion of the IVS was found to be similar to the aggregate vessel (AGG) motion. The diagnostic quality of the coronary vessels for the quiescent phases calculated from the aggregate vessel (PAGG) and IVS (PIV S) deviation signal using the proposed methods was comparable to the quiescent phases calculated by the CT scanner (PCT). The one exception was the RCA, which improved for PAGG for 18 of the 20 subjects when compared to PCT (PCT = 2.48; PAGG = 2.07, p = 0.001)., Conclusions: A method for quantifying the motion of specific coronary vessels using a correlation-based, phase-to-phase deviation measure was developed and tested on 20 patients receiving cardiac CT exams. The IVS was found to be a suitable predictor of vessel quiescence. The diagnostic quality of the quiescent phases detected by the proposed methods was comparable to those calculated by the CT scanner. The ability to quantify coronary vessel quiescence from the motion of the IVS can be used to develop new CTCA gating techniques and quantify the resulting potential improvement in CTCA image quality.

Online social networking services have changed the way we interact as a society and offer many opportunities to improve the way we practice radiology and medicine in general. This article begins with an introduction to social networking. Next, the latest advances in online social networking are reviewed, and areas where radiologists and clinicians may benefit from these new tools are discussed. This article concludes with several steps that the interested reader can take to become more involved in online social networking., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Objective: Contagious infectious diseases add a new dimension to radiology and pose many unanswered questions. In particular, what is the safest way to image patients with contagious and potentially lethal infectious diseases? Here, we describe protocols used by Emory University to successfully acquire chest radiographs of patients with Ebola virus disease., Conclusion: Radiology departments need to develop new protocols for various modalities used in imaging patients with contagious and potentially lethal infectious diseases.

The rapid advances in mobile computing technology have the potential to change the way radiology and medicine as a whole are practiced. Several mobile computing advances have not yet found application to the practice of radiology, while others have already been applied to radiology but are not in widespread clinical use. This review addresses several areas where radiology and medicine in general may benefit from adoption of the latest mobile computing technologies and speculates on potential future applications., (Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: Anti-1-amino-3-[(18)F]fluorocyclobutane-1-carboxylic acid (anti-3-[(18)F]FACBC) is a synthetic amino acid positron emission tomography (PET) radiotracer with utility in detection of prostate carcinoma and brain tumors and has also been shown to have uptake in lung tumor cell lines. The purpose of this study is to determine the uptake characteristics of anti-3-[(18)F]FACBC in lung carcinoma and if this radiotracer may help characterize pulmonary lesions., Procedures: Ten patients with pulmonary lesions scheduled for surgical resection or biopsy underwent 45-min dynamic PET-CT imaging of the thorax after IV injection of 214.6-384.8MBq of anti-3-[(18)F]FACBC. Anti-3-[(18)F]FACBC uptake was compared with that of routine 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) PET-CT scans of the same patient and validated with a combination of pathology, imaging and clinical follow-up. Immunohistochemistry for Ki-67 was performed on tissue samples., Results: There were nine malignant (seven lung nodules and two mediastinal nodes), two inflammatory, and one carcinoid lesion ranging from 1 to 3.75 cm. Mean(±SD) SUVmax of malignant lesions was 6.2(±2.6), 5.9(±2.7), 5.9(±3.4), and 5.7(±3.3), at 8, 16, 28, and 40 min, respectively; while for inflammatory lesions at the same time points, 4.1(±0.6), 3.3(±0.9), 2.2(±0.03), and 2.3(±0.03), respectively. The carcinoid tumor had SUVmax of 2.8, 2.6, 1.5, and 0.9 at similar time points. Mean SUVmax of all malignant lesions was higher than that of inflammatory lesions for anti-3-[(18)F]FACBC, and was statistically significant at greater than 28 min post-radiotracer infusion (p < 0.05). There was no significant correlation of anti-3-[(18)F]FACBC activity with Ki67, though there was a positive trend. There was a strong correlation between anti-3-[(18)F]FACBC and [(18)F]FDG uptake., Conclusions: Anti-3-[(18)F]FACBC uptake in malignant lesions is greater than in inflammatory lesions with a higher degree of separation of uptake on delayed imaging. More comprehensive study is required to determine the diagnostic performance of anti-3-[(18)F]FACBC in the characterization of pulmonary lesions.

Many of the statistical methods currently employed to analyze fMRI data depend on a response template. However, the true form of the hemodynamic response, and thereby the response template, is often unknown. Consequently, cluster analysis provides a complementary, template-free method for exploratory analysis of multidimensional fMRI data sets. Clustering algorithms currently being applied to fMRI data separate the data into a predefined number of clusters (k). A poor choice of k will result in erroneously partitioning well-defined clusters. Although several clustering algorithms have been successfully applied to fMRI data, techniques for statistically testing cluster separation are still lacking. To address this problem we suggest a method based on Fisher's linear discriminant and the bootstrap. Also introduced in this paper is a measure based on the projection of multidimensional data from two clusters onto the vector, maximizing the ratio of the between- to the within-cluster sums of squares. The resulting one-dimensional distribution may be readily visualized and used as a heuristic for estimating cluster homogeneity. These methods are demonstrated for the self-organizing maps clustering algorithm when applied to event-related fMRI data.

In this paper, Kohonen's self-organizing mapping (SOM) is used as a data-driven technique for analyzing functional magnetic resonance imaging (fMRI) data. Upon the completion of an SOM analysis, a cluster merging technique, based on examining the reproducibility of the fMRI data across epochs, is utilized to merge SOM nodes whose feature vectors are sufficiently similar to one another. The resulting 'super nodes' give time course templates of potential interest. These templates can be subsequently used in traditional template-based analysis methods, such as cross-correlation analysis, yielding statistical maps and activation patterns. This technique has been demonstrated on two fMRI datasets obtained from a visually-guided motor paradigm and a visual paradigm, respectively, showing satisfactory results.

Template-based activation detection methods, such as cross-correlation, could be difficult to apply in event-related functional MRI data because accurate a priori knowledge about the activation signal patterns is often not available. As a result, several categories of template-free data analysis techniques have been introduced in the fMRI literature. One previously described template-free activation detection technique is based on the feature that activated voxels yield reproducible time course patterns as the subject undergoes the same simulation in repeated epochs. In this paper, spatial information is incorporated as a second feature and a combined univariate measure is formed. The resulting method is shown to offer measurable improvement in detecting activation regions in simulated data in a highly computationally efficient manner. Its practical utility is demonstrated with an experimental data set obtained with a visually guided motor paradigm.

A significant recent development in functional magnetic resonance imaging (fMRI) is the introduction of event-related fMRI, also known as time-resolved fMRI. Because the exact shape of the MR response in an event-related fMRI experiment is often not known, traditional methods developed for block design experiments, such as t test and correlation analysis, are not well-suited for extracting activated pixels from the event-related data. In this work, a statistical technique based on nonadditive two-way analysis of variance is developed for use in event-related studies. Theoretical and experimental work were carried out for establishing a statistical threshold to determine pixel activation. Experimental studies were performed to demonstrate the utility of this approach., (Copyright 2001 Academic Press.)

The relative intensities of glare spots in the image of an electrodynamically trapped aerosol droplet are measured experimentally with an aerosol particle microscope and calculated theoretically. The theoretical calculations are in good agreement with these experiments and indicate that the intensities of these spots are extremely sensitive to the imaginary part of the refractive index. Experimentally, we obtain the molecular absorption spectrum of an impurity within a droplet by recording the spectrum of an individual glare spot produced by broadband illumination.