Evaluating the effectiveness of different perceptual training methods in a difficult visual discrimination task with ultrasound images.

Recent work has shown that perceptual training can be used to improve the performance of novices in real-world visual classification tasks with medical images, but it is unclear which perceptual training methods are the most effective, especially for difficult medical image discrimination tasks. We investigated several different perceptual training methods with medically naïve participants in a difficult radiology task: identifying the degree of hepatic steatosis (fatty infiltration of the liver) in liver ultrasound images. In Experiment 1a (N = 90), participants completed four sessions of standard perceptual training, and participants in Experiment 1b (N = 71) completed four sessions of comparison training. There was a significant post-training improvement for both types of training, although performance was better when the trained task aligned with the task participants were tested on. In both experiments, performance initially improves rapidly, with learning becoming more gradual after the first training session. In Experiment 2 (N = 200), we explored the hypothesis that performance could be improved by combining perceptual training with explicit annotated feedback presented in a stepwise fashion. Although participants improved in all training conditions, performance was similar regardless of whether participants were given annotations, or underwent training in a stepwise fashion, both, or neither. Overall, we found that perceptual training can rapidly improve performance on a difficult radiology task, albeit not to a comparable level as expert performance, and that similar levels of performance were achieved across the perceptual training paradigms we compared.

Chest imaging findings in COVID-19-positive patients in an Australian tertiary hospital.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has infected over 215 million individuals worldwide. Chest radiographs (CXR) and computed tomography (CT) have assisted with diagnosis and assessment of COVID-19. Previous reports have described peripheral and lower zone predominant opacities on chest radiographs. Whilst the most common patterns on CT are bilateral, peripheral basal predominant ground glass opacities (Wong et al., Radiology, 296, 2020, E72; Karimian and Azami, Pol J Radiol, 86, 2021, e31). This study describes the imaging findings in an Australian tertiary hospital population. METHODS: COVID-PCR-positive patients who had chest imaging (CXR, CT and ventilation perfusion (V/Q) scans) from January 2020 to August 2020 were included. Distribution, location and pattern of involvement was recorded. Evaluation of the assessors was performed using Fleiss Kappa calculations for review of radiographic findings and qualitative analysis of CT findings. RESULTS: A total of 681 studies (616 CXRs, 59 CTs, 6 V/Q) from 181 patients were reviewed. The most common chest radiograph finding was bilateral lower lobe predominant diffuse opacification and most common CT pattern being ground glass opacities. Of the CT imaging, 33 were CT Pulmonary Angiograms of which five demonstrated acute pulmonary emboli. There was good inter-rater agreement between radiologists in assessment of imaging appearances on CXR (kappa 0.29-0.73) and CT studies. CONCLUSION: A review of imaging in an Australian tertiary hospital demonstrates similar patterns of COVID-19 infection on chest X-ray and CT imaging when compared to the international population.

USPSTF2013 versus PLCOm2012 lung cancer screening eligibility criteria (International Lung Screening Trial): interim analysis of a prospective cohort study.

BACKGROUND: Lung cancer is a major health problem. CT lung screening can reduce lung cancer mortality through early diagnosis by at least 20%. Screening high-risk individuals is most effective. Retrospective analyses suggest that identifying individuals for screening by accurate prediction models is more efficient than using categorical age-smoking criteria, such as the US Preventive Services Task Force (USPSTF) criteria. This study prospectively compared the effectiveness of the USPSTF2013 and PLCOm2012 model eligibility criteria. METHODS: In this prospective cohort study, participants from the International Lung Screening Trial (ILST), aged 55-80 years, who were current or former smokers (ie, had ≥30 pack-years smoking history or ≤15 quit-years since last permanently quitting), and who met USPSTF2013 criteria or a PLCOm2012 risk threshold of at least 1·51% within 6 years of screening, were recruited from nine screening sites in Canada, Australia, Hong Kong, and the UK. After enrolment, patients were assessed with the USPSTF2013 criteria and the PLCOm2012 risk model with a threshold of at least 1·70% at 6 years. Data were collected locally and centralised. Main outcomes were the comparison of lung cancer detection rates and cumulative life expectancies in patients with lung cancer between USPSTF2013 criteria and the PLCOm2012 model. In this Article, we present data from an interim analysis. To estimate the incidence of lung cancers in individuals who were USPSTF2013-negative and had PLCOm2012 of less than 1·51% at 6 years, ever-smokers in the Prostate Lung Colorectal and Ovarian Cancer Screening Trial (PLCO) who met these criteria and their lung cancer incidence were applied to the ILST sample size for the mean follow-up occurring in the ILST. This trial is registered at ClinicalTrials.gov, NCT02871856. Study enrolment is almost complete. FINDINGS: Between June 17, 2015, and Dec 29, 2020, 5819 participants from the International Lung Screening Trial (ILST) were enrolled on the basis of meeting USPSTF2013 criteria or the PLCOm2012 risk threshold of at least 1·51% at 6 years. The same number of individuals was selected for the PLCOm2012 model as for the USPSTF2013 criteria (4540 [78%] of 5819). After a mean follow-up of 2·3 years (SD 1·0), 135 lung cancers occurred in 4540 USPSTF2013-positive participants and 162 in 4540 participants included in the PLCOm2012 of at least 1·70% at 6 years group (cancer sensitivity difference 15·8%, 95% CI 10·7-22·1%; absolute odds ratio 4·00, 95% CI 1·89-9·44; p<0·0001). Compared to USPSTF2013-positive individuals, PLCOm2012-selected participants were older (mean age 65·7 years [SD 5·9] vs 63·3 years [5·7]; p<0·0001), had more comorbidities (median 2 [IQR 1-3] vs 1 [1-2]; p<0·0001), and shorter life expectancy (13·9 years [95% CI 12·8-14·9] vs 14·8 [13·6-16·0] years). Model-based difference in cumulative life expectancies for those diagnosed with lung cancer were higher in those who had PLCOm2012 risk of at least 1·70% at 6 years than individuals who were USPSTF2013-positive (2248·6 years [95% CI 2089·6-2425·9] vs 2000·7 years [1841·2-2160·3]; difference 247·9 years, p=0·015). INTERPRETATION: PLCOm2012 appears to be more efficient than the USPSTF2013 criteria for selecting individuals to enrol into lung cancer screening programmes and should be used for identifying high-risk individuals who benefit from the inclusion in these programmes. FUNDING: Terry Fox Research Institute, The UBC-VGH Hospital Foundation and the BC Cancer Foundation, the Alberta Cancer Foundation, the Australian National Health and Medical Research Council, Cancer Research UK and a consortium of funders, and the Roy Castle Lung Cancer Foundation for the UK Lung Screen Uptake Trial.

A randomized trial comparing the effects of sternal band and plate fixation of the sternum with that of figure-of-8 wires on sternal edge motion and quality of recovery after cardiac surgery.

OBJECTIVES: We sought to compare the effects of conventional wire cerclage with that of the band and plate fixation of the sternum. METHODS: A parallel randomized open-label trial with 1:1 allocation ratio compared healing after adult cardiac surgery using 'figure-of-8' stainless steel wire cerclage or a band and plate system (plates). The primary end point was maximal sternal edge displacement during active coughing of ≥2 mm in ≥2 of 4 sites measured with ultrasound by 2 assessors blinded to the other at 6 weeks postoperatively. Secondary end points at 12 weeks included ultrasound assessment, computed tomography (CT) scan and multidimensional assessment of quality of recovery using the Postoperative Quality of Recovery Scale. RESULTS: Of 50 patients, 26 received plates and 24 wires. Two patients died and 1 withdrew consent leaving 25 plates and 22 wires for primary end point analysis. Operations included 37 coronary, 5 valve and 8 combined coronary and valve procedures. At 6 weeks, less sternal movement was observed in patients with plates than those with wires, 4% (1/25) vs 32% (7/22), P = 0.018. Agreement between observers was high, kappa = 0.850. At 12 weeks, less ultrasound motion was seen in patients with plates, 0% (0/23) than those with wires, 25% (5/20), P = 0.014. Recovery from pain was higher for patients with plates 92% (22/24) than those with wires 67% (14/21), P = 0.004. CT bone edge separation was less for plates 38% (9/24) than wires 71% (15/21), P = 0.036. CT mild bone synthesis or greater was similar between patients with plates 21% (5/24) and wires 14% (3/21), P = 0.71. CONCLUSIONS: Patients receiving the band and plate system had significantly less sternal edge motion than those receiving wires, 6 and 12 weeks after cardiac surgery and experienced less pain. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov NCT03282578.

Turbulent flow artefact mimicking central pulmonary emboli in pulmonary hypertension: A report of two cases.

Many artefacts can mimic pulmonary emboli (PE) on CT pulmonary angiography (CTPA), most commonly in the peripheral pulmonary arteries (PA's). We describe flow-related artefact mimicking PE in the central PA's of two patients, both with pulmonary arterial hypertension (PAH). To our knowledge, this is the first report of this PE mimic in the central PA's.

Rare manifestation of Neurofibromatosis type 1: A plexiform neurofibroma involving the mediastinum and lungs with endobronchial neurofibromata.

Neurofibromatosis type 1 (NF1) is a multisystem phakomatosis. The intrathoracic manifestations of NF1 are protean. We describe a rare case of a plexiform neurofibroma infiltrating the mediastinum and lungs with multiple endobronchial neurofibromata. To our knowledge, a mediastinal plexiform neurofibroma extending into the lungs on CT has not been reported.

Computer vs human: Deep learning versus perceptual training for the detection of neck of femur fractures.

INTRODUCTION: To evaluate the accuracy of deep convolutional neural networks (DCNNs) for detecting neck of femur (NoF) fractures on radiographs, in comparison with perceptual training in medically-naïve individuals. METHODS: This study extends a previous study that conducted perceptual training in medically-naïve individuals for the detection of NoF fractures on a variety of dataset sizes. The same anteroposterior hip radiograph dataset was used to train two DCNNs (AlexNet and GoogLeNet) to detect NoF fractures. For direct comparison with perceptual training results, deep learning was completed across a variety of dataset sizes (200, 320 and 640 images) with images split into training (80%) and validation (20%). An additional 160 images were used as the final test set. Multiple pre-processing and augmentation techniques were utilised. RESULTS: AlexNet and GoogLeNet DCNNs NoF fracture detection accuracy increased with larger training dataset sizes and mildly with augmentation. Accuracy increased from 81.9% and 88.1% to 89.4% and 94.4% for AlexNet and GoogLeNet respectively. Similarly, the test accuracy for the perceptual training in top-performing medically-naïve individuals increased from 87.6% to 90.5% when trained on 640 images compared with 200 images. CONCLUSIONS: Single detection tasks in radiology are commonly used in DCNN research with their results often used to make broader claims about machine learning being able to perform as well as subspecialty radiologists. This study suggests that as impressive as recognising fractures is for a DCNN, similar learning can be achieved by top-performing medically-naïve humans with less than 1 hour of perceptual training.

Perceptual training to improve hip fracture identification in conventional radiographs.

Diagnosing certain fractures in conventional radiographs can be a difficult task, usually taking years to master. Typically, students are trained ad-hoc, in a primarily-rule based fashion. Our study investigated whether students can more rapidly learn to diagnose proximal neck of femur fractures via perceptual training, without having to learn an explicit set of rules. One hundred and thirty-nine students with no prior medical or radiology training were shown a sequence of plain film X-ray images of the right hip and for each image were asked to indicate whether a fracture was present. Students were told if they were correct and the location of any fracture, if present. No other feedback was given. The more able students achieved the same level of accuracy as board certified radiologists at identifying hip fractures in less than an hour of training. Surprisingly, perceptual learning was reduced when the training set was constructed to over-represent the types of images participants found more difficult to categorise. Conversely, repeating training images did not reduce post-training performance relative to showing an equivalent number of unique images. Perceptual training is an effective way of helping novices learn to identify hip fractures in X-ray images and should supplement the current education programme for students.

Accessible or inaccessible? Diagnostic efficacy of CT-guided core biopsies of head and neck masses.

PURPOSE: Tissue sampling of lesions in the head and neck is challenging due to complex regional anatomy and sometimes necessitates open surgical biopsy. However, many patients are poor surgical candidates due to comorbidity. Thus, we evaluated the use of CT guidance for establishing histopathological diagnosis of head and neck masses. METHODS: All consecutive patients (n = 22) who underwent CT-guided core biopsy of head or neck masses between April 2009 and August 2012 were retrospectively reviewed using the departmental CT interventional procedures database. The indication for each biopsy performed was to establish or exclude a diagnosis of neoplasia in patients with suspicious head or neck lesions found on clinical examination or imaging studies. Patients received conscious sedation and 18 G, semiautomated core needle biopsies were performed by experienced neuroradiologists using 16-slice multidetector row CT imaging guidance (Somatom Definition Siemens Medical Solutions, Germany). Histopathology results of each biopsy were analysed. RESULTS: Sixteen of 22 biopsies that were performed (73 %) yielded a pathological diagnosis. Anatomic locations biopsied included: masticator (n = 7), parapharyngeal (n = 3), parotid (n = 3), carotid (n = 3), perivertebral (n = 3), pharyngeal (n = 2), and retropharyngeal (n = 1) spaces. Six biopsies (27 %) were nondiagnostic due to inadequate tissue sampling, particularly small biopsy sample size and failure to biopsy the true sampling site due to extensive necrosis. No major complications were encountered. CONCLUSIONS: The use of CT guidance to perform core biopsies of head and neck masses is an effective means of establishing histopathological diagnosis and reduces the need for diagnostic open surgical biopsy and general anaesthesia.

Stage of change behavioral assessment tool fails to predict the prevalence of chlamydia in an urban adolescent health clinic.

STUDY OBJECTIVE: Strategies to reduce STI among adolescents and young adults have failed to consistently demonstrate effectiveness. A universal approach may not be appropriate because individuals are at different stages with respect to self-management behaviors. Thus, the Stage of Change Transtheoretical Model has been advocated. This study was conducted to determine whether staging could be accomplished in an urban adolescent clinic and whether it provides a tool to predict STI risk. DESIGN: Participants were interviewed and staged according to a standardized instrument with respect to sexual risk behaviors and contraceptive use. SETTING: Urban adolescent health clinic. PARTICIPANTS: 103 females (ages 18-24). INTERVENTIONS: A physical examination and diagnostic tests for syphilis, HSV, HCV, chlamydia, gonorrhea and HPV were performed. MAIN OUTCOME MEASURES: Stages for behaviors to reduce STI risk and to utilize contraception and STI prevalence. RESULTS: 78% of the participants were in the three earliest stages of behavior (precontemplative, contemplative, and ready for action) with respect to condom use for STI prevention; conversely only 47% were in early stages with respect to birth control practices. Of the participants tested, 12/81 (15%) had chlamydial infection detected by molecular techniques, whereas no participants had gonorrhoeae. Among the subset tested for HPV DNA, 18/45 (40%) were positive. The diagnostic behavior stage for STI prevention did not correlate with the presence of chlamydia. CONCLUSIONS: A staging instrument can be implemented into adolescent health clinic practice, but cannot be used as a risk assessment tool for the presence of chlamydia. Additionally females are more likely to protect themselves against pregnancy than against an STI.