Machine learning and glioma imaging biomarkers.

AIM: To review how machine learning (ML) is applied to imaging biomarkers in neuro-oncology, in particular for diagnosis, prognosis, and treatment response monitoring. MATERIALS AND METHODS: The PubMed and MEDLINE databases were searched for articles published before September 2018 using relevant search terms. The search strategy focused on articles applying ML to high-grade glioma biomarkers for treatment response monitoring, prognosis, and prediction. RESULTS: Magnetic resonance imaging (MRI) is typically used throughout the patient pathway because routine structural imaging provides detailed anatomical and pathological information and advanced techniques provide additional physiological detail. Using carefully chosen image features, ML is frequently used to allow accurate classification in a variety of scenarios. Rather than being chosen by human selection, ML also enables image features to be identified by an algorithm. Much research is applied to determining molecular profiles, histological tumour grade, and prognosis using MRI images acquired at the time that patients first present with a brain tumour. Differentiating a treatment response from a post-treatment-related effect using imaging is clinically important and also an area of active study (described here in one of two Special Issue publications dedicated to the application of ML in glioma imaging). CONCLUSION: Although pioneering, most of the evidence is of a low level, having been obtained retrospectively and in single centres. Studies applying ML to build neuro-oncology monitoring biomarker models have yet to show an overall advantage over those using traditional statistical methods. Development and validation of ML models applied to neuro-oncology require large, well-annotated datasets, and therefore multidisciplinary and multi-centre collaborations are necessary.

The Fellowship of the Royal College of Radiologists (FRCR) examination: a review of the evidence.

The Fellowship of the Royal College of Radiologists (FRCR) examination is the professional qualification that is essential for career progression in clinical radiology within the UK. It is also important for career progression in many countries internationally. The FRCR has evolved and changed over the last decade. In this systematic review we appraise and summarise the available data relating to the FRCR emphasising the published evidence regarding the validity, reliability, and acceptability of this examination. Comparison is made to other equivalent medical examinations, as well as a more recently published commissioned external review of the FRCR examinations. The Clinical Radiology Part 2B (CR2B) examination in its pre-existing format is reliable, valid, and acceptable. Recommendations from the commissioned external review are based primarily on expert opinion, with a limited evidence base comprising data from a small sample acquired during a single examination sitting and without peer review. Unlike the CR2B examination, there is little evidence regarding assessment of the CR1 and CR2 examinations. Both the CR1 and CR2 examinations are currently in the process of undergoing major changes to their formats. Blueprinting items to the curriculum might improve acceptability. Other changes may improve transparency and reliability of these assessments. Our analysis and many aspects of the external review may provide pointers regarding how the upcoming data produced by the "automated" FRCR examinations can be further analysed to provide a more robust evaluation.

Performance in the FRCR (UK) Part 2B examination: analysis of factors associated with success.

AIM: To assess factors that influence pass rates and examination scores in the Fellowship of the Royal College of Radiologists (FRCR) 2B examination. MATERIALS AND METHODS: 2238 attempts at the FRCR 2B examination were evaluated between Spring 2006 and Spring 2010. Pass rates and examination scores were analysed by gender and ethnicity, and the influence of factors such as radiology training (UK versus non-UK), sitting (Spring versus Autumn), and the presence of an undergraduate or postgraduate degree were examined. RESULTS: 1571 candidates made 2238 examination attempts, with an overall pass rate of 59.4% (63.1% at first attempt). 66.2% entrants were male; 48.8% attempts were by candidates from a UK radiology training scheme. UK candidates were significantly more likely to pass than non-UK candidates (p < 0.0001). White candidates were more likely to pass at first or second attempt than non-white candidates (p < 0.0001), but when restricted to UK entrants ethnicity did not influence success at first attempt. Overall, females were more successful than males (p < 0.001). Presence of an undergraduate (p = 0.19) or postgraduate (p = 0.80) degree did not affect pass rate at first attempt for UK candidates. However, logistic regression demonstrated that the only significant factor influencing pass rates at first attempt was whether radiology training was undertaken in the UK (p < 0.0001). A trend towards increased pass rates in autumn sittings was seen (p = 0.06), but ethnicity (p = 0.99) and gender (p = 0.41) were not significant factors. CONCLUSION: The FRCR 2B examination is non-discriminatory for UK candidates with respect to gender and ethnicity. Poorer performance of non-UK trained candidates is a consistent outcome in the literature.

The FRCR 2B oral examination: is it reliable?

AIM: To investigate the reliability of the oral component of the Fellowship of the Royal College of Radiologists (FRCR) 2B examination. MATERIALS AND METHODS: Anonymized candidate test scores were analysed from nine consecutive sittings of the FRCR 2B oral examination covering the period from spring 2006 to spring 2010. Interobserver reliability was assessed using weighted Kappa coefficient, intraclass correlation coefficient, and a modified Bland-Altman plot. RESULTS: During the study period, 2235 candidates sat the FRCR 2B examination. Eighty-five point one percent of candidates obtained paired oral assessment scores within one mark of each other. This figure rises to 95.7% for paired scores within 1.5 marks of each other. Mean difference in scores was 0.67 (95% CI: 0.65-0.70). Agreement rises at the extremities of mean score. Reliability coefficients for the FRCR 2B oral examination were calculated as 0.27 (weighted Kappa) and 0.44 (intraclass correlation coefficient). CONCLUSION: The calculated reliability coefficients indicate fair to, at best, moderate interobserver reliability in the FRCR 2B oral examination. These findings are disappointing but are comparable with other oral assessment reliability studies. There is scope for improvement, although further work to measure the combined reliability of all the components of the FRCR 2B examination is desirable. Measures that could potentially increase reliability must be carefully considered against any negative impact on test validity, acceptability, and cost.

Training the next generation of radiology researchers. Report on a joint meeting of the Royal College of Radiologists and the Wellcome Trust and an overview of College strategies in developing radiology research.

As the use of imaging continues to increase in medical research, the Royal College of Radiologists (RCR) Research Committee and the Wellcome Trust held a joint meeting in 2010 to explore the current issues critical to training the next generation of radiology researchers. It was stated that despite an increase in consultant radiologist numbers, the number of academic posts has declined. This has resulted in radiology lagging behind some of the other specialties in terms of research activity and output. Some of the obstacles arising from the meeting have since been addressed by the RCR. These and other possible solutions that emanated from the interactive sessions include establishing a research culture in radiology departments, establishing a network of research radiologist mentors, improving trainee opportunities, and improving consultant opportunities. The meeting demonstrated the demand and need for extended support for research activity from the RCR. The RCR Academic Committee is formulating recommendations based on these and other sources of evidence. However, it is acknowledged that this comes at a time when national financial resources for research support are severely limited. Research in radiology remains an important part of the future development of the specialty. Supporting the next generation of potential researchers is essential, and this meeting was a means to understand how this might best be achieved.

Update on imaging of non-infectious musculoskeletal complications of HIV infection.

Acquired immunodeficiency syndrome (AIDS) results from infection with human immunodeficiency virus (HIV), producing an immunodeficient state and severe pathology across multiple organ systems. Musculoskeletal involvement is particularly prevalent in this population with both infectious and non-infectious complications encountered, but it is suggested that the latter will affect 72% of HIV-infected individuals. In this review we aim to provide an update on the imaging characteristics of the non-infectious manifestations. The conditions include HIV-related arthritis as well as various malignancies, myositis, anaemia, osteonecrosis, rhabdomyolysis, hypertrophic osteoarthropathy and therapy-related side effects. For the clinician, the diagnostic challenge lies in differentiating disease-related symptoms from therapy-related side effects, particularly when clinical and laboratory features can be non-specific. This is especially difficult following the widespread introduction of highly active anti-retroviral therapy (HAART). Imaging investigations and MRI in particular have proven vital for facilitating early diagnosis and enabling prompt treatment. Furthermore, wider availability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has allowed whole-body assessment for staging and treatment response of malignancy. Understanding the pathogenesis of the various conditions and recognising their imaging features is essential for the clinical radiologist.

The FRCR 2B examination: a survey of candidate perceptions and experiences.

AIM: To survey the views of recent candidates of the Fellowship of the Royal College of Radiologists (FRCR) 2B examination with reference to assessment validity, reliability, and acceptability. MATERIALS AND METHODS: One thousand, two hundred and four UK radiology trainees and consultants were invited to complete an automated internet questionnaire regarding their experiences and perceptions of the FRCR 2B examination. The questionnaire was informed by a review of the literature. Eligible participants were candidates who had taken the examination within the previous 3 years. RESULTS: Four hundred and ninety-seven out of 1204 (41%) responses were received; of which 258/497 (52% of respondents) were eligible for inclusion into the study. The rapid reporting component is perceived to be significantly fairer than the oral section (82 versus 70% agree; p<0.001). The oral component fared poorly in perceived performance-reducing anxiety levels but well in questions relating to validity and reliability. Female candidates are more likely to find the FRCR 2B unfair (p=0.01) and experience performance-reducing anxiety (p<0.001) than males. No gender differences were observed in first-time pass rates (p=0.6). Candidate first language did not affect anxiety levels (p=0.9) or first-time pass rates (p=0.06). Only 12% of candidates agreed that the oral examination should move to an objective structured clinical format. CONCLUSION: Candidates score the FRCR 2B examination well in test validity with little desire for change to the oral examination format. Efforts to help reduce anxiety levels in the oral component would improve perceived fairness.

Imaging of primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) comprises 5% of all primary brain tumours. PCNSL demonstrates a variety of well-documented imaging findings, which can vary depending on immune status and histological type. Imaging features of PCNSL may overlap with other tumours and infection making definitive diagnosis challenging. In addition, several rare variants of PCNSL have been described, each with their own imaging characteristics. Advanced imaging techniques including 2-[(18)F]-fluoro-2-deoxy-d-glucose ((18)FDG) and (11)C positron-emission tomography (PET), (201)Tl single-photon emission computed tomography (SPECT), (1)H-magnetic resonance spectroscopy (MRS), and MR perfusion, have been used to aid differentiation of PCNSL from other tumours. Ultimately, no imaging method can definitively diagnose PCNSL, and histology is required.

COVID-19 Stroke Apical Lung Examination Study: A Diagnostic and Prognostic Imaging Biomarker in Suspected Acute Stroke.

BACKGROUND AND PURPOSE: Diagnosis of coronavirus disease 2019 (COVID-19) relies on clinical features and reverse-transcriptase polymerase chain reaction testing, but the sensitivity is limited. Carotid CTA is a routine acute stroke investigation and includes the lung apices. We evaluated CTA as a potential COVID-19 diagnostic imaging biomarker. MATERIALS AND METHODS: This was a multicenter, retrospective study (n = 225) including CTAs of patients with suspected acute stroke from 3 hyperacute stroke units (March-April 2020). We evaluated the reliability and accuracy of candidate diagnostic imaging biomarkers. Demographics, clinical features, and risk factors for COVID-19 and stroke were analyzed using univariate and multivariate statistics. RESULTS: Apical ground-glass opacification was present in 22.2% (50/225) of patients. Ground-glass opacification had high interrater reliability (Fleiss κ = 0.81; 95% CI, 0.68-0.95) and, compared with reverse-transcriptase polymerase chain reaction, had good diagnostic performance (sensitivity, 75% [95% CI, 56-87]; specificity, 81% [95% CI, 71-88]; OR = 11.65 [95% CI, 4.14-32.78]; P < .001) on multivariate analysis. In contrast, all other contemporaneous demographic, clinical, and imaging features available at CTA were not diagnostic for COVID-19. The presence of apical ground-glass opacification was an independent predictor of increased 30-day mortality (18.0% versus 5.7%, P = .017; hazard ratio = 3.51; 95% CI, 1.42-8.66; P = .006). CONCLUSIONS: We identified a simple, reliable, and accurate COVID-19 diagnostic and prognostic imaging biomarker obtained from CTA lung apices: the presence or absence of ground-glass opacification. Our findings have important implications in the management of patients presenting with suspected stroke through early identification of COVID-19 and the subsequent limitation of disease transmission.

Outcome Study of the Pipeline Embolization Device with Shield Technology in Unruptured Aneurysms (PEDSU).

BACKGROUND AND PURPOSE: The recently introduced Pipeline Flex Embolization Device with Shield Technology (Pipeline Shield) is the third generation of Pipeline flow-diverter devices. It has a new stent-surface modification, which reduces thrombogenicity. We aimed to evaluate clinical and radiographic (safety and efficacy) outcomes of the Pipeline Shield. MATERIALS AND METHODS: The 30-day and 1-year mortality and morbidity rates and the 6- and 18-month radiographic aneurysm occlusion outcomes for procedures performed between March 2016 and January 2018 were analyzed. 3D-TOF-MRA was used for follow-up. RESULTS: Forty-four attempted Pipeline Shield procedures were performed for 41 patients with 44 target aneurysms (total of 52 aneurysms treated). A total of 88.5% of devices were inserted in the anterior circulation, and 11.5%, in the posterior circulation; 49/52 (94.2%) aneurysms were saccular; and 1/52 (1.9%) was fusiform. One (1.9%) aneurysm was an iatrogenic pseudoaneurysm, and 1 (1.9%) was a dissecting aneurysm. Seventy-one percent (35/49) of the saccular aneurysms were wide-neck (neck, >4 mm), 34.6% (18/52) were large (≥10 mm), and 3.8% (2/52) were giant (≥25 mm). The mean aneurysm sac maximal diameter was 9.0 mm, and the mean neck width was 5.0 mm. The cumulative mortality and morbidity rates were 2.3% and 6.8% at 1 year, respectively. The adequate occlusion rate was 78.8% at 6 months and 90.3% at 18 months. CONCLUSIONS: In this pragmatic and non-industry-sponsored study, the occlusion rates and safety outcomes were similar to those seen in previously published studies with flow-diverter devices and earlier generation Pipeline Embolization Devices.