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Competence by Design (CBD) is a medical education initiative instituted by the Royal College of Physicians and Surgeons of Canada to improve the training of resident physicians in specialty disciplines. CBD integrates Competency Based Medical Education with traditional specialty discipline post-graduate medical education (PGME) training through the application of an organizational framework of competencies. Various specialty disciplines in Canada have transitioned to CBD since 2017 in a staggered approach. Diagnostic radiology PGME programs in Canada are expected to transition to CBD in 2022 for the incoming resident physician cohort. This article reviews potential challenges to the implementation of CBD in diagnostic radiology PGME programs and proposes evidence-informed targeted strategies and solutions to address these challenges. It is important for diagnostic radiology PGME programs to understand the challenges pertaining to the implementation of CBD so that they may be able to successfully implement this or similar medical education initiatives in their programs. Moreover, as radiology subspecialty PGME programs, such as nuclear medicine, interventional radiology, neuroradiology, and pediatric radiology, likewise transition to CBD and diagnostic radiology PGME programs internationally increasingly implement other Competency Based Medical Education models, the implications of the challenges pertaining to the implementation of CBD will further become of increasing importance.

Purpose Total kidney volume (TKV) measurement is integral in clinical management of autosomal dominant polycystic kidney disease (ADPKD) but the gold standard of measurement via stereology/manual planimetry is time-consuming and not readily available to clinicians. This study assessed whether standardized measurement instructions based on an ellipsoid equation enhanced TKV assessment on computed tomographic (CT) images of the kidneys as determined by accuracy, reproducibility, efficiency and/or user acceptability. Methods Participating radiologists were randomized to perform TKV measurements with or without standardized instructions. All participants measured the same 3 non-contrast, low-dose CT scans. Accuracy was assessed as variation from TKV measurements obtained by planimetry. Intraclass correlation coefficients and time to complete the measurements were assessed. Surveys assessed prior experience with TKV measurement and user acceptability of the instructions. Results 49 radiologists participated. There was no difference in accuracy or measurement time between instructed and non-instructed participants. There was a trend towards greater reproducibility with standardized instructions (ICC .8 vs .6). 92% of respondents indicated the instructions were easy to use, 86% agreed the instructions would enhance their comfort with TKV measurement and 75% agreed they would recommend these instructions to colleagues. Conclusions Instructed and non-instructed participants demonstrated similar accuracy and time required for TKV measurement, but instructed participants had a trend towards greater reproducibility. There was high acceptability including enhanced user confidence with the instructions. Standardized instructions may be of value for radiologists seeking to improve their confidence in providing clinicians with TKV measurements necessary to appropriately manage this patient population.

Background Existing CT emphysema measurements quantify the extent or clustering of emphysema voxels in chronic obstructive pulmonary disease (COPD); however, these measurements do not quantify how those voxels are clustered. Purpose To develop a CT measurement to quantify the "compactness" of emphysema voxels, called the normalized join count (NJC), and to determine whether the NJC measurement differentiates COPD disease severity and correlates with lung function and visual emphysema scores. Materials and Methods In this secondary analysis of a prospective study, lung function and CT images were obtained from the Canadian Cohort Obstructive Lung Disease study visit 1 from 2009 to 2013. Participants were categorized as never-smokers, at risk, mild COPD, or moderate-severe COPD. Diffusion capacity for carbon monoxide/alveolar volume was measured. CT emphysema was scored visually by radiologists. CT measurements included the percentage low-attenuation area with attenuation less than -950 HU (%LAA-950insp), low-attenuation cluster (LAC), and lowest 15th percentile point of the CT lung density histogram. NJC was developed to measure compactness of CT emphysema voxels. An analysis of variance determined differences between groups. Multivariable ridge regression determined association between CT measurements with lung function and radiologist scores. Results A total of 1294 participants (750 men; mean age, 67 years ± 10) were analyzed (277 never-smokers, 306 at risk, 427 mild COPD, and 284 moderate-severe COPD). NJC, %LAA-950insp, and LAC measurements were higher in moderate-severe COPD than in never-smokers and at-risk participants (P < .05 for all comparisons), but only NJC was different between mild and ;moderate-severe COPD (mean, 1.98% ± 3.61 vs 1.44% ± 2.14; P < .05). In multivariable regression analysis, among all CT measurements NJC had the greatest relative contribution to diffusion capacity for carbon monoxide/alveolar volume (P = .002) and visual emphysema score (P < .001). Conclusion The relationship of normalized join count with severity of chronic obstructive pulmonary disease may indicate that the assessment of this disease is dependent on the number of low attenuating voxels or the size of clusters and the spatial arrangement of such voxels. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Grenier in this issue.

Introduction: We evaluated knowledge and perceptions of an established Competency-Based Medical Education (CBME) model developed by the Royal College of Physicians and Surgeons of Canada, Competence by Design (CBD), and identified evidence-informed priorities for professional development activities (PDAs). Materials and Methods: Teaching faculty and residents at a single, large diagnostic radiology post-graduate medical education (PGME) program were eligible to participate in this cross-sectional, survey-based study. Knowledge of CBD was evaluated through multiple choice questions (MCQs), which assessed participants’ understanding of major principles and terms associated with CBD. Participants’ perceptions of the anticipated impact of CBD on resident education and patient care were evaluated and priorities for PDAs were identified, which informed a framework for CBD PDAs. Results: Fifty faculty and residents participated. The faculty and resident response rates were 11.6% (n = 29/249) and 55.3% (n = 21/38), respectively. The mean ± standard deviation overall score on MCQs was 39.0% ± 20.4%. The majority of participants perceived the impact of CBD on resident education to be equivocal and to not impact patient care. Knowledge of CBD was not statistically significantly associated with participants’ perceptions of the impact of CBD on either resident education or patient care ( P > .05). Delivery of high-quality feedback was the greatest priority identified for PDAs. Discussion: Our results and proposed CBD PDAs framework may help to guide diagnostic radiology PGME programs in designing evidence-informed PDAs, which may meaningfully contribute to the successful implementation of CBD in diagnostic radiology PGME. As diagnostic radiology PGME programs throughout the world increasingly implement CBME models, evidence-informed PDAs will become of increasing importance.

The investigation of acute pulmonary embolism is a common task for radiologists in Canada. Technical image quality and reporting quality must be excellent; pulmonary embolism is a life-threatening disease that should not be missed but overdiagnosis and unnecessary treatment should be avoided. The most frequently performed imaging investigation, computed tomography pulmonary angiogram (CTPA), can be limited by poor pulmonary arterial opacification, technical artifacts and interpretative errors. Image quality can be affected by patient factors (such as body habitus, motion artifact and cardiac output), intravenous (IV) contrast protocols (including the timing, rate and volume of IV contrast administration) and common physics artifacts (including beam hardening). Mimics of acute pulmonary embolism can be seen in normal anatomic structures, disease in non-vascular structures and pulmonary artery filling defects not related to acute pulmonary emboli. Understanding these pitfalls can help mitigate error, improve diagnostic quality and optimize patient outcomes. Dual energy computed tomography holds promise to improve imaging diagnosis, particularly in clinical scenarios where routine CTPA may be problematic, including patients with impaired renal function and patients with altered cardiac anatomy.

Background: Patients with significant (≥50%) left main disease (LMD) have a high risk of cardiovascular events, and guidelines recommend revascularization to improve survival. However, the impact of intermediate LMD (stenosis, 25%–49%) on outcomes is unclear. Methods: Randomized ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) participants who underwent coronary computed tomography angiography at baseline were categorized into those with (25%–49%) and without ( Results: Among the 3699 participants who satisfied the inclusion criteria, 962 (26%) had intermediate LMD. Among invasive strategy participants with intermediate LMD on coronary computed tomography angiography, 49 (7.0%) had significant (≥50% stenosis) left main stenosis on invasive angiography. Patients with intermediate LMD had a higher risk of cardiovascular events in the unadjusted but not in the fully adjusted model compared with those without intermediate LMD. An invasive strategy increased procedural MI and decreased nonprocedural MI with no significant difference for other outcomes including the primary end point. There was no meaningful heterogeneity of treatment effect based on intermediate LMD status except for nonprocedural MI for which there was a greater absolute reduction with invasive management in the intermediate LMD group (−6.4% versus −2.0%; P interaction =0.049). The invasive strategy improved angina-related quality of life and the benefit was durable throughout follow-up without significant heterogeneity based on intermediate LMD status. Conclusions: In the ISCHEMIA trial, there was no meaningful heterogeneity of treatment benefit from an invasive strategy regardless of intermediate LMD status except for a greater absolute risk reduction in nonprocedural MI with invasive management in those with intermediate LMD. An invasive strategy increased procedural MI, reduced nonprocedural MI, and improved angina-related quality of life. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01471522.

The Coronavirus disease 2019 (COVID-19) pandemic has altered how medical education is delivered, worldwide. Didactic sessions have transitioned to electronic/online platforms and clinical teaching opportunities are limited. These changes will affect how radiology is taught to medical students at both the pre-clerkship (ie, year 1 and 2) and clinical (ie, year 3 and 4) levels. In the pre-clerkship learning environment, medical students are typically exposed to radiology through didactic lectures, integrated anatomy laboratories, case-based learning, and ultrasound clinical skills sessions. In the clinical learning environment, medical students primarily shadow radiologists and radiology residents and attend radiology resident teaching sessions. These formats of radiology education, which have been the tenets of the specialty, pose significant challenges during the pandemic. This article reviews how undergraduate radiology education is affected by COVID-19 and explores solutions for teaching and learning based on e-learning and blended learning theory.

Rationale: Measuring disease extent and progression of systemic sclerosis-associated interstitial lung disease (SSc-ILD) is challenging, with recent studies suggesting potential utility of quantitative measurements from computed tomography (CT) scans.Objectives: To determine the associations of quantitative computed tomography (qCT) density-based measures with physiological parameters, visual CT scores, and survival in patients with SSc-ILD.Methods: Patients with SSc-ILD and volumetric high-resolution CT images with ≤1.25-mm slice thickness were retrospectively identified. Cardiothoracic radiologists produced visual CT scores of ground glass, reticulation, and honeycombing, with visual fibrosis score equaling the sum of reticulation and honeycombing. qCT measurements included high-attenuation areas (HAA), skewness, kurtosis, and mean lung attenuation (MLA). Associations of qCT measures with pulmonary physiology, visual CT scores, and mortality were analyzed using Spearman's rank correlation and Cox regression.Results: A total of 503 CT scans from 170 patients with SSc-ILD were included. qCT HAA, skewness, kurtosis, and MLA were associated with lung function and visual fibrosis scores, independent of age, sex, and pack-years, using both baseline and change data. Baseline and changes in qCT measures (except ∆skewness) were associated with mortality on unadjusted analysis. Changes in all qCT variables remained associated with survival after adjustment for baseline age, sex, pack-years, and lung function, but not when adjusting for changes in lung function. ∆HAA and ∆MLA were associated with survival after adjustment for age, sex, pack-years, and change in visual CT scores.Conclusions: CT density measurements correlate with physiologic impairment and visual CT scores in patients with SSc-ILD; however, they were not associated with survival independent of changes in pulmonary physiology. The clinical utility of more sophisticated qCT measures should be explored.

On March 11, 2020, the World Health Organization declared infection related to a novel coronavirus (SARS-CoV-2) a pandemic. The role and impact of imaging predates this declaration and continues to change rapidly. This article is a consensus statement provided by the Canadian Society of Thoracic Radiology and the Canadian Association of Radiologists outlining the role of imaging in COVID-19 patients. The objectives are to answer key questions related to COVID-19 imaging of the chest and provide guidance for radiologists who are interpreting such studies during this pandemic. The role of chest radiography (CXR), computed tomography (CT), and lung ultrasound is discussed. This document attempts to answer key questions for the imager when dealing with this crisis, such as “When is CXR appropriate in patients with suspected or confirmed COVID-19 infection?” or “How should a radiologist deal with incidental findings of COVID-19 on CT of the chest done for other indications?” This article also provides recommended reporting structure for CXR and CT, breaking diagnostic possibilities for both CXR and CT into 3 categories: typical, nonspecific, and negative based on imaging findings with representative images provided. Proposed reporting language is also outlined based on this structure. As our understanding of this pandemic evolves, our appreciation for how imaging fits into the workup of patients during this unprecedented time evolves as well. Although this consensus statement was written using the most recent literature, it is important to maintain an open mind as new information continues to surface.

The diagnosis of acute appendicitis (AA) in pregnancy remains challenging. We investigated which preoperative clinical factors are most predictive of AA in pregnant women.164 pregnant patients undergoing magnetic resonance imaging for suspected AA were retrospectively reviewed. Logistic regression was used to compare those with pathologically confirmed AA and those without.28 patients (17.1%) had pathologically confirmed AA. 42.9% (n = 12) were perforated at the time of operation. Factors associated with AA included history of emesis (p = 0.005), migratory abdominal pain (p = 0.006), rebound tenderness (p = 0.01), elevated white blood cell count (p = 0.003), elevated Alvarado Score (p 0.001), elevated neutrophil count (p = 0.021), and left shift (p = 0.001). As a screening test, a left shift with neutrophils70% provided a sensitivity and negative predictive value of 100.0%.Every patient in our series with AA had a left shift. Neutrophil count and percentage should be considered in the diagnostic evaluation of these patients to better guide resource utilization and treatment.

Accurate separation of idiopathic pulmonary fibrosis from fibrotic (chronic) hypersensitivity pneumonitis is crucial to patient management, but is frequently a difficult problem. Our objective was to identify pathologic variables that help make this separation. Clinical, radiological, and pathologic data were re-reviewed for 23 patients with a fibrotic interstitial lung disease and biopsy suggesting idiopathic pulmonary fibrosis or fibrotic hypersensitivity pneumonitis. Clinical features, high-resolution computed tomography, and surgical lung biopsies were each examined independently using a prespecified approach. This was followed by a multidisciplinary discussion in which the likelihood of an idiopathic pulmonary fibrosis diagnosis was assigned by the clinician alone based only on clinical data, by the clinician and radiologist based on integrated clinical and radiologic data, and by the clinician, radiologist, and pathologist based on all three domains. A higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis was associated with older age at diagnosis, male sex, higher forced vital capacity, and absence of ground glass changes. Pathologic variables associated with a higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis included increased number of fibroblast foci/cm2 and increased subpleural fibrosis. Pathologic variables associated with a higher multidisciplinary discussion-based confidence of hypersensitivity pneumonitis included an increased fraction of bronchioles with peribronchiolar metaplasia, increased foci of peribronchiolar metaplasia/cm2, and presence of giant cells/granulomas. These results provide guidance in separating idiopathic pulmonary fibrosis from hypersensitivity pneumonitis; however, a third of cases could not be confidently classified even when using these pathologic features combined with clinical and radiologic information in a multidisciplinary discussion.

Background: The development of irreversible airway obstruction (IRAO) in asthma is related to lung/airway inflammatory and structural changes whose characteristics are likely influenced by exposure to tobacco smoke. Objective: To investigate the interplay between airway and lung structural changes, airway inflammation, and smoking exposure in asthmatics with IRAO. Methods: We studied asthmatics with IRAO who were further classified according to their smoking history, those with ≥20 pack-years of tobacco exposure (asthmatics with smoking-related IRAO [AwS-IRAO]) and those with Results: Ninety patients were recruited (57 AwS-IRAO and 33 AwNS-IRAO). There were no statistically significant differences in the extent of emphysema and gas trapping between groups on quantitative chest CT analysis, although Pi10, a marker of airway wall thickness, was significantly higher in AwS-IRAO (p = 0.0242). Visual analysis showed a higher prevalence of emphysema (p = 0.0001) and higher emphysema score (p < 0.0001) in AwS-IRAO compared to AwNS-IRAO and distribution of emphysema was different between groups. Correlations between radiological features and lung function were stronger in AwS-IRAO. In a subgroup analysis, we found a correlation between airway neutrophilia and emphysematous features in AwS-IRAO and between eosinophilia and both airway wall thickness and emphysematous changes in AwNS-IRAO. Conclusions: Although bronchial structural changes were relatively similar in smoking and nonsmoking patients with asthma and IRAO, emphysematous changes were more predominant in smokers. However, neutrophils in AwS-IRAO and eosinophils in AwNS-IRAO were associated with lung and airway structural changes.

OBJECTIVE. Underrepresentation of women in the top hierarchy of academic medicine exists despite women comprising more than half of the medical school graduates and residency positions. The purpose of this study is to analyze and quantify the relationship of gender, research productivity, and career advancement in Canadian academic radiology departments. MATERIALS AND METHODS. Seventeen academic radiology departments with affiliated residency programs in Canada were searched for publicly available data on faculty to generate a database for gender and academic profiles of the radiologists. Bibliometric data were collected using Scopus archives. The associations of gender, academic ranks, and leadership positions were assessed, and a p value of ≤ 0.05 was defined as significant. Significant variables were analyzed using a multivariate linear regression model. RESULTS. Of 1266 faculty members, gender information and academic rank were available for 932 faculty members: 597 (64.05%) were men and 335 (35.95%) were women (χ2 = 21.82; p < 0.0001). Of a total of 563 assistant professors, 331 (58.79%) were men and 232 (41.21%) were women; of 258 associate professors, 177 (68.60%) were men and 81 (31.40%) were women; and of 111 professors, 89 (80.18%) were men and 22 (19.82%) were women. The gender gap widens at higher academic ranks, displaying a threefold drop in the ratio of women holding the rank of full professor (6.57%) compared with 14.91% male professors; 29.55% of women radiologists have first-in-command leadership positions compared with 70.45% of men. A comparable or higher h-index is noted for women Canadian radiologists after adjusting for number of citations, number of publications, and years of active research. CONCLUSION. Canadian academic radiology departments have fewer women radiologists in senior faculty and leadership positions. Our study results show that Canadian female radiologists at the professor level have more publications than their male counterparts.

Rationale: To improve disease outcomes in idiopathic pulmonary fibrosis (IPF), it is essential to understand its early pathophysiology so that it can be targeted therapeutically. Objectives: Perfor...

Background Etiologies of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are heterogeneous. We phenotyped severe AECOPD based on molecular pathogen detection of sputum samples collected at hospitalization of COPD patients and determined their outcomes. Methods We phenotyped 72 sputum samples of COPD patients who were hospitalized with a primary diagnosis of AECOPD using a molecular array that detected common bacterial and viral respiratory pathogens. Based on these results, the patients were classified into positive or negative pathogen groups. The pathogen-positive group was further divided into virus or bacteria subgroups. Admission day 1 blood samples were assayed for N-terminal prohormone brain natriuretic peptide, CRP, and complete blood counts. Results A total of 52 patients had a positive result on the array, while 20 patients had no pathogens detected. The most common bacterial pathogen detected was Haemophilus influenzae and the most common virus was rhinovirus. The pathogen-negative group had the worse outcomes with longer hospital stays (median 6.5 vs 5 days for bacteria-positive group, P=0.02) and a trend toward increased 1-year mortality (P=0.052). The bacteria-positive group had the best prognosis, whereas the virus-positive group had outcomes somewhere in between the bacteria-positive and pathogen-negative groups. Conclusion Molecular diagnostics on sputum can rapidly phenotype serious AECOPD into bacteria-, virus-, or pathogen-negative groups. The bacteria-positive group appears to have the best prognosis, while pathogen-negative group has the worst. These data suggest that AECOPD is a heterogeneous event and that accurate phenotyping of AECOPD may lead to novel management strategies that are personalized and more precise.

Previous studies have suggested that interstitial lung disease (ILD) progresses most rapidly early in the course of systemic sclerosis-associated (SSc)-ILD, and that SSc-ILD is often more stable or even "burned out" after the first 4 years following diagnosis.Our objectives were to determine whether an apparent plateau in pulmonary function decline is due to survival bias and to identify distinct prognostic phenotypes of ILD progression.Consecutive patients with SSc-ILD from a single center were included. Pulmonary function measurements were typically performed every 6 months. Study participants were categorized into long-term survivors (8 yr survival from diagnosis), and those with medium-term and short-term mortality (4-8 and4 yr survival, respectively). We excluded those censored with less than 8 years of follow-up. Subject-specific slopes for change in forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (DlThe cohort included 171 study participants with SSc-ILD. A plateau in the progression of FVC was apparent in the full cohort analysis but disappeared with stratification into prognostic subgroups to account for survival bias. Those with short-term mortality had a higher annual rate of decline in FVC (-4.10 [95% confidence interval (CI), -7.92 to -0.28] vs. -2.14 [95% CI, -3.31 to -0.97] and -0.94 [-1.46 to -0.42]; P = 0.003) and DlAdults with SSc-ILD have distinct patterns of physiological progression that remain relatively consistent during long-term follow-up; however, recent change in FVC cannot be used to predict future change in FVC within shorter follow-up intervals. The findings of this study provide important information on the course of disease in SSc-ILD and identify specific phenotypes of progression that may improve clinical decision-making and design of future therapeutic trials.

ObjectivesThe aim of this study was to compare respiratory and patient-reported outcome measures (PROMs) between 3 and 6 months after symptom onset and to identify features that predict these changes.MethodsThis was a consecutive prospective cohort of 73 patients who were hospitalised with coronavirus disease 2019 (COVID-19). We evaluated the changes in pulmonary function tests and PROMs between 3 and 6 months and then investigated the associations between outcomes (change in diffusing capacity of the lung for carbon monoxide (DLCO), dyspnoea and quality of life (QoL)) and clinical and radiological features.ResultsThere was improvement in forced vital capacity, total lung capacity and DLCO between 3 and 6 months by 3.25%, 3.82% and 5.69%, respectively; however, there was no difference in PROMs. Reticulation and total computed tomography (CT) scores were associated with lower DLCO % predicted at 6 months (coefficients; −8.7 and −5.3, respectively). The association between radiological scores and DLCO were modified by time, with the degree of association between ground glass and DLCO having decreased markedly over time. There was no association between other predictors and change in dyspnoea or QoL over time.ConclusionsThere is improvement in pulmonary function measurements between 3 and 6 months after COVID-19 symptom onset; however, PROMs did not improve. A higher reticulation and total CT score are negatively associated with DLCO, but this association is attenuated over time. Lastly, there is a considerable proportion of patients with unexplained dyspnoea at 6 months, motivating further research to identify the underlying mechanisms.

Acute pulmonary embolism (APE) is a well-recognized cause of circulatory system compromise and even demise which can frequently present a diagnostic challenge for the physician. The diagnostic challenge is primarily due to the frequency of indeterminate presentations as well as several other conditions which can have a similar clinical presentation. This often obliges the physician to establish a firm diagnosis due to the potentially serious outcomes related to this disease. Computed tomography pulmonary angiography (CTPA) has increasingly cemented its role as the primary investigation tool in this clinical context and is widely accepted as the standard of care due to several desired attributes which include great accuracy, accessibility, rapid turn-around time and the ability to suggest an alternate diagnosis when APE is not the culprit. In Part 1 of this guidance document, a series of up-to-date recommendations are provided to the reader pertaining to CTPA protocol optimization (including scan range, radiation and intravenous contrast dose), safety measures including the departure from breast and gonadal shielding, population-specific scenarios (pregnancy and early post-partum) and consideration of alternate diagnostic techniques when clinically deemed appropriate.

BACKGROUND The role of MRI-detected EMVI (mrEMVI) as a reliable prognostic factor in rectal cancer has been emphasized in recent years but this finding remains underreported by many institutions. OBJECTIVE This review aimed to demonstrate the importance of pre- and post-treatment MRI-detected EMVI as independent prognostic factors of adverse oncologic outcomes in patients undergoing neoadjuvant therapy followed by total mesorectal excision. METHODS This review was designed using the PRISMA guidelines. The following electronic databases were searched from January 2002 to January 2020: CENTRAL, Ovid MEDLINE, PubMed and Ovid Embase. Main outcomes included disease-free survival (DFS) and overall survival (OS). Other outcomes of interest comprised positive resection margin and synchronous metastases. RESULTS Seventeen studies involving a total of 3821 patients were included for data synthesis. For pre-neoadjuvant treatment mrEMVI, pooled hazard ratio (HR) estimate for DFS was 2.30 (95%CI 1.54-3.44) for higher recurrence in mrEMVI-positive patients. mrEMVI-positive patients were found to have a lower OS with a pooled HR of 1.68 (95%CI 1.27-2.22). Pooled risk ratio (RR) for synchronous metastasis was 4.11 (95%CI 2.80-6.02) for mrEMVI-positivity. For post-neoadjuvant treatment EMVI (ymrEMVI), positive status showed a lower DFS with a pooled HR of 2.04 (95%CI 1.55-2.69). RR of having a positive resection margin status was 2.95 (95%CI 1.75-4.98) for ymrEMVI-positive patients. CONCLUSION This review showed that oncologic outcomes are significantly worse for both pre- and post-neoadjuvant treatment mrEMVI-positive patients. MRI-detected EMVI should be consistently reported in rectal cancer staging and may provide guidance for the targeted use of additional systemic therapy.

ObjectivesThis study aimed to examine the concordance of coronary computed tomographic angiography (CCTA) assessment of coronary anatomy and invasive coronary angiography (ICA) as the reference standard in patients enrolled in the ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches).BackgroundPerformance of CCTA compared with ICA has not been assessed in patients with very high burdens of stress-induced ischemia and a high likelihood of anatomically significant coronary artery disease (CAD). A blinded CCTA was performed after enrollment to exclude patients with left main (LM) disease or no obstructive CAD before randomization to an initial conservative or invasive strategy, the latter guided by ICA and optimal revascularization.MethodsRates of concordance were calculated on a per-patient basis in patients randomized to the invasive strategy. Anatomic significance was defined as≥50% diameter stenosis (DS) for both modalities. Sensitivity analyses using a threshold of≥70% DS for CCTA or considering only CCTA images of good-to-excellent quality were performed.ResultsIn 1,728 patients identified by CCTA as having no LM disease ≥50% and at least single-vessel CAD, ICA confirmed 97.1% without LM disease≥50%, 92.2% with at least single-vessel CAD and no LM disease≥50%, and only 4.9% without anatomically significant CAD. Results using a≥70% DS threshold or only CCTA of good-to-excellent quality showed similar overall performance.ConclusionsCCTA before randomization in ISCHEMIA demonstrated high concordance with subsequent ICA for identification of patients with angiographically significant disease without LM disease.

The long-term respiratory morbidity of COVID-19 remains unclear. We describe the clinical, radiological and pulmonary function abnormalities that persist in previously hospitalised patients assessed 12 weeks after COVID-19 symptom onset, and identify clinical predictors of respiratory outcomes. At least one pulmonary function variable was abnormal in 58% of patients and 88% had abnormal imaging on chest CT. There was strong association between days on oxygen supplementation during the acute phase of COVID-19 and both DLCO-% (diffusion capacity of the lung for carbon monoxide) predicted and total CT score. These findings highlight the need to develop treatment strategies and the importance of long-term respiratory follow-up after hospitalisation for COVID-19.

At our institution, on-call radiology residents perform emergent ultrasounds (US) outside of departmental working hours. The aim of the study was to evaluate radiology resident-performed US for clinically suspected acute appendicitis in women under the age of 40.Retrospective review of 104 consecutive US scans outside of departmental working hours by radiology residents, and 104 consecutive US studies scanned during departmental working hours by sonographers, in women under the age of 40 for clinically suspected appendicitis .Appendix visualization rate was 27% for the resident group (sonographer group: 30%, p = 0.759). The sensitivity and specificity of US for appendicitis were 63% (95% confidence interval: 41%-81%) and 98% (95% CI: 91%-100%), respectively for the resident group (sonographer group: 69% [95% CI: 41%-89 %] and 98% [95% CI: 92%-100%], respectively). An alternative cause for right lower quadrant pain was offered in 17% of resident group cases (sonographer group: 21%, p = 0.598). Follow-up CT or MRI was performed in 47% of resident cases (sonographer group: 44%, p = 0.781). Residents performed more focused US (i.e. not imaging the pelvic organs), at 34% (sonographer group: 1%, p0.001). When only focused scanning was performed by residents, there was a trend toward increased downstream imaging (CT or MRI), odds ratio = 2.76 (95% CI: 0.99-7.70).Out-of-hours US scans performed by radiology residents had similar performance characteristics compared to departmental sonographers. We discovered an increased rate of downstream imaging in cases in which residents performed limited scans and did not document visualization of the pelvic organs.

Background Coronary artery calcification is a significant contributor to reduced accuracy of coronary computed tomographic angiography (CTA) in the assessment of coronary artery disease severity. The aim of the current study is to assess the impact of a prototype calcium deblooming algorithm on the diagnostic accuracy of CTA. Methods 40 patients referred for invasive catheter angiography underwent CTA and invasive catheter angiography. The CTA were reconstructed using a standard soft tissue kernel (CTASTAND) and a deblooming algorithm (CTADEBLOOM). CTA studies were read with and without the deblooming algorithm blinded to the invasive coronary angiogram findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value for the detection of stenosis ≥50% or ≥70% were evaluated using quantitative coronary angiography as the reference standard. Image quality was assessed using a 5-point scale, and the presence of image artifact recorded. Results All studies were diagnostic with 548 segments available for evaluation. Image score was 3.64 ± 0.72 with CTADEBLOOM, versus 3.56 ± 0.72 with CTASTAND (p = 0.38). CTADEBLOOM had significantly less calcium blooming artifact than CTASTAND (12.5% vs. 47.5%, p = 0.001). Based on a 50% stenosis threshold for defining significant disease, the Sensitivity/Specificity/PPV/NPV/Accuracy were 65.9/84.9/27.6/96.6/83.4 for CTADEBLOOM and 75.0/81.9/26.6/97.4/81.4 for CTASTAND using a ≥50% threshold. CTADEBLOOM specificity was significantly higher than CTASTAND (84.9% vs. 81.5%, p = 0.03), with no difference between the algorithms in sensitivity (p = 0.22), or accuracy (p = 0.15). These results remained unchanged when a stenosis threshold of ≥70% was used. Interobserver agreement was fair with both techniques (CTADEBLOOM k = 0.38, CTASTAND k = 0.37). Conclusion In this proof of concept study, coronary calcification deblooming using a prototype post-processing algorithm is feasible and reduces calcium blooming with an improvement of the specificity of the CTA exam.

Rationale and Aim As medical schools reduce the hours of anatomy teaching, residents in anatomy-intensive residency programs like radiology must independently acquire the anatomy knowledge needed to achieve competency. The purpose of this study was to develop and evaluate a 4-week competency-based self-directed anatomy rotation for junior residents. Methods Seven post-graduate year 1 (PGY-1) radiology residents completed a 4-week rotation of radiologic anatomy. The objectives were developed from standards, senior residents, and expert opinion, and the competency-based curriculum included self-directed modules. Pre-course and post-course tests were administered and test scores were compared using an unpaired t test. In addition, PGY-1 residents completed a course evaluation and survey regarding their anatomy knowledge and anatomy exposure prior to completing the course. Results Out of the 25 points available, the average pre-test score was 10.79 ± 2.78 (range 8–16.5), and the average post-test score was 21.64 ± 2.23 (range 18.5–25). This difference was statistically significant ( P < .0001). The PGY-1 residents reported receiving < 10% of dedicated radiologic anatomy teaching prior to residency and felt unprepared for the anatomy required in residency. Overall, residents felt more confident in looking at images after completing the self-directed radiologic anatomy course. Conclusion This study demonstrates the feasibility of creating a self-directed course for radiology residents that significant improves their anatomy knowledge. Given the trend in medical undergraduate education away from dedicated anatomy teaching, residency programs should consider addressing anatomy education more formally for junior residents to ensure that trainees receive the foundational knowledge required for residency.

Background The objective of this study was to evaluate the performance of dual-energy computed tomography (DECT) for preoperative parathyroid tumor (PT) localization in primary hyperparathyroid (PHP) patients. Methods A retrospective review was carried out of the medical records of all PHP patients who underwent ultrasound (US), Tc-99m sestamibi noncontrast single photon emission computed tomography (CT-MIBI), DECT and parathyroidectomy at a single center. Results The sensitivities and accuracies for preoperative PT localization in the 97 patient study population were: US 40% and 93%, CT-MIBI 64.0% and 97%, and DECT 84% and 96%, respectively. In the one third of the study population that did not localize preoperatively with CT-MIBI and US, DECT correctly localized a PT in 21 cases (66%). DE-CT and US correctly localized a PT in 86% of cases, and only 5 (8%) of the cases that were accurately localized by a combination of CT-MIBI and US were not identified by DE-CT. Conclusions DECT should be utilized as a first line preoperative PT localization study in PHP patients, and is also a sensitive salvage localization test.

Background and objective It is unknown whether oesophageal disease is associated with systemic sclerosis-associated interstitial lung disease (SSc-ILD) severity, progression or mortality. Methods High-resolution computed tomography (HRCT) scans from 145 SSc-ILD patients were scored for fibrosis score, oesophageal diameter and presence of hiatal hernia. Fibrosis asymmetry was calculated as: (most affected side - least affected side)/(most affected side + least affected side). Mixed effects models were used for repeated measures analyses. Results Mean fibrosis score was 8.6%, and most patients had mild-to-moderate physiological impairment. Every 1 cm increase in oesophageal diameter was associated with 1.8% higher fibrosis score and 5.5% lower forced vital capacity (FVC; P ≤ 0.001 for unadjusted and adjusted analyses). Patients with hiatal hernia had 3.9% higher fibrosis score, with persistent differences on adjusted analysis (P = 0.001). Oesophageal diameter predicted worsening fibrosis score over the subsequent year (P = 0.02), but not when adjusting for baseline fibrosis score (P = 0.16). Oesophageal diameter was independently associated with mortality (P = 0.001). Oesophageal diameter was not associated with asymmetric disease or radiological features of gross aspiration. Conclusion Oesophageal diameter and hiatal hernia are independently associated with SSc-ILD severity and mortality, but not with ILD progression or asymmetric disease. Oesophageal disease is unlikely to be a significant driver of ILD progression in SSc.

Studies of excised lungs show that significant airway attrition in the "quiet" zone occurs early in chronic obstructive pulmonary disease (COPD).To determine if the total number of airways quantified in vivo using computed tomography (CT) reflects early airway-related disease changes and is associated with lung function decline independent of emphysema in COPD.Participants in the multicenter, population-based, longitudinal CanCOLD (Canadian Chronic Obstructive Lung Disease) study underwent inspiratory/expiratory CT at visit 1; spirometry was performed at four visits over 6 years. Emphysema was quantified as the CT inspiratory low-attenuation areas below -950 Hounsfield units. CT total airway count (TAC) was measured as well as airway inner diameter and wall area using anatomically equivalent airways.Participants included never-smokers (n = 286), smokers with normal spirometry at risk for COPD (n = 298), Global Initiative for Chronic Obstructive Lung Disease (GOLD) I COPD (n = 361), and GOLD II COPD (n = 239). TAC was significantly reduced by 19% in both GOLD I and GOLD II compared with never-smokers (P 0.0001) and by 17% in both GOLD I and GOLD II compared with at-risk participants (P 0.0001) after adjusting for low-attenuation areas below -950 Hounsfield units. Further analysis revealed parent airways with missing daughter branches had reduced inner diameters (P 0.0001) and thinner walls (P 0.0001) compared with those without missing daughter branches. Among all CT measures, TAC had the greatest influence on FEVTAC may reflect the airway-related disease changes that accumulate in the "quiet" zone in early/mild COPD, indicating that TAC acquired with commercially available software across various CT platforms may be a biomarker to predict accelerated COPD progression.

Nawaf M Alotaibi,1,2 Virginia Chen,1,3,4 Zsuzsanna Hollander,1,3,4 Cameron J Hague,5 Darra T Murphy,5 Jonathon A Leipsic,5 Mari L DeMarco,1,6 J Mark FitzGerald,7,8 Bruce M McManus,1,3,4,6 Raymond T Ng,4,9 Don D Sin1,3,7 1Centre for Heart Lung Innovation, James Hogg Research Centre, St Paul’s Hospital, Vancouver, BC, Canada; 2Division of Pulmonary Medicine, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 3Institute for Heart Lung Health, 4PROOF Centre of Excellence, 5Department of Radiology, St Paul’s Hospital, 6Department of Pathology and Laboratory Medicine, 7Division of Respiratory Medicine, Department of Medicine, University of British Columbia, 8The Lung Centre, Vancouver General Hospital, 9Department of Computer Sciences, University of British Columbia, Vancouver, BC, Canada Rationale: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are caused by a variety of different etiologic agents. Our aim was to phenotype COPD exacerbations using imaging (chest X-ray [CXR] and computed tomography [CT]) and to determine the possible role of the blood tests (C-reactive protein [CRP], the N-terminal prohormone brain natriuretic peptide [NT-proBNP]) as diagnostic biomarkers. Materials and methods: Subjects who were hospitalized with a primary diagnosis of AECOPD and who had had CXRs, CT scans, and blood collection for CRP and NT-proBNP were assessed in this study. Radiologist blinded to the clinical and laboratory characteristics of the subjects interpreted their CXRs and CT images. ANOVA and Spearman’s correlation were performed to test for associations between these imaging parameters and the blood-based biomarkers NT-proBNP and CRP; logistic regression models were used to assess the performance of these biomarkers in predicting the radiological parameters. Results: A total of 309 subjects were examined for this study. Subjects had a mean age of 65.6±11.1 years, 66.7% of them were males, and 62.4% were current smokers, with a mean FEV1 54.4%±21.5% of predicted. Blood NT-proBNP concentrations were associated with cardiac enlargement (area under the curve [AUC] =0.72, P

Background and objective The objectives of this study were to determine the prevalence and characteristics of cough in idiopathic pulmonary fibrosis (IPF), chronic hypersensitivity pneumonitis (HP) and systemic sclerosis-associated interstitial lung disease (SSc-ILD). Methods Cough severity was measured in consecutive patients with IPF (n = 77), HP (n = 32) and SSc-ILD (n = 67) using a 10-cm visual analogue scale (VAS). Dyspnoea and quality of life were measured using established questionnaires. Cough severity was compared across ILD subtypes and predictors of cough severity were determined using multivariate analysis. Results Cough was more common in IPF and chronic HP compared to SSc-ILD (87% and 83% vs 68%, P = 0.02). The median (interquartile range) VAS score was 39 (17–65) in the IPF cohort, 29 (11–48) in HP and 18 (0–33) in SSc-ILD (P

Introduction We sought to validate whether low dose CACS CT with hybrid IR (HIR) could replace standard dose filtered back projection (FBP). Method We enrolled 100 patients to undergo low dose CACS CT with HIR, in addition to routine full dose FBP. Results No significant difference between full and low dose CT in Agatston score 138.2±360.6 vs. 137.3±356.4 (p=0.272) or calcium mass score 19±48.3 vs. 18.7±49 (p=0.8), respectively. Bland–Altman analysis showed no systematic bias. Calcium volume difference was statistically significant 57.2±134 vs. 55.1±130.2 (p=0.001). Conclusion Low dose CT for calcium scoring with HIR enables stable CACS Agatston score and calcium mass quantification as compared to full dose FBP.

ERUS and MRI are used for preoperative imaging of rectal cancer. Here, we compare ERUS and MRI for accuracy of CRM prediction at mid- and distal rectal locations. In retrospective review, 20 rectal cancer patients having TME surgery had both ERUS and MRI preoperatively: 8 mid rectum and 12 in distal rectum. Predicted CRM by ERUS and MRI were compared to TME pathology. Overall, predicted CRM was 6.5 ± 3.6 mm by ERUS, 7.7 ± 5.0 mm by MRI, and 6.0 ± 4.6 mm by pathology. Overall, correlation coefficients to pathology were 0.77 (p = 0.0004) for ERUS and 0.64 (p = 0.008) for MRI. In distal rectum, correlation coefficients were 0.71 (p = 0.02) for ERUS and −0.10 (p = 0.79) for MRI. In mid rectum, correlation coefficients were 0.92 (p = 0.01) for ERUS and 0.44 (p = 0.38) for MRI. While MRI is used routinely for preoperative rectal cancer imaging, ERUS can provide additional assessment of CRM for mid or distal rectal lesions. Further investigation is needed to support these preliminary ERUS CRM findings in mid and distal rectum.

Background: Disease accumulates in the small airways without being detected by conventional measurements. Objectives: To quantify small airway disease using a novel computed tomography (CT) inspiratory-to-expiratory approach called the disease probability measure (DPM) and to investigate the association with pulmonary function measurements. Methods: Participants from the population-based CanCOLD study were evaluated using full-inspiration/full-expiration CT and pulmonary function measurements. Full-inspiration and full-expiration CT images were registered, and each voxel was classified as emphysema, gas trapping (GasTrap) related to functional small airway disease, or normal using two classification approaches: parametric response map (PRM) and DPM (VIDA Diagnostics, Inc., Coralville, IA, USA). Results: The participants included never-smokers (n = 135), at risk (n = 97), Global Initiative for Chronic Obstructive Lung Disease I (GOLD I) (n = 140), and GOLD II chronic obstructive pulmonary disease (n = 96). PRMGasTrap and DPMGasTrap measurements were significantly elevated in GOLD II compared to never-smokers (p < 0.01) and at risk (p < 0.01), and for GOLD I compared to at risk (p < 0.05). Gas trapping measurements were significantly elevated in GOLD II compared to GOLD I (p < 0.0001) using the DPM classification only. Overall, DPM classified significantly more voxels as gas trapping than PRM (p < 0.0001); a spatial comparison revealed that the expiratory CT Hounsfield units (HU) for voxels classified as DPMGasTrap but PRMNormal (PRMNormal- DPMGasTrap = -785 ± 72 HU) were significantly reduced compared to voxels classified normal by both approaches (PRMNormal-DPMNormal = -722 ± 89 HU; p < 0.0001). DPM and PRMGasTrap measurements showed similar, significantly associations with forced expiratory volume in 1 s (FEV1) (p < 0.01), FEV1/forced vital capacity (p < 0.0001), residual volume/total lung capacity (p < 0.0001), bronchodilator response (p < 0.0001), and dyspnea (p < 0.05). Conclusion: CT inspiratory-to-expiratory gas trapping measurements are significantly associated with pulmonary function and symptoms. There are quantitative and spatial differences between PRM and DPM classification that need pathological investigation.

Hypersensitivity pneumonitis (HP) is characterized by inflammation of the lung parenchyma that is induced by exposure to an inhaled organic antigen. We present a case of recurrent, acute HP caused by repeated transient exposure to a down sleeping bag in a patient with a family history of chronic bird-associated hypersensitivity pneumonitis. The patient's recurrent symptoms, changes in physiology, and radiographic findings coincided with repeated exposure to this source. It was later confirmed that the patient's sister had also developed chronic HP from recurrent exposure to household birds. This case highlights recent studies implicating gene-exposure interactions in the development of HP. Keywords: Hypersensitivity pneumonitis, Familial hypersensitivity pneumonitis, Organic antigen, Interstitial lung disease

Accurate separation of idiopathic pulmonary fibrosis from fibrotic (chronic) hypersensitivity pneumonitis is crucial to patient management, but is frequently a difficult problem. Our objective was to identify pathologic variables that help make this separation. Clinical, radiological, and pathologic data were re-reviewed for 23 patients with a fibrotic interstitial lung disease and biopsy suggesting idiopathic pulmonary fibrosis or fibrotic hypersensitivity pneumonitis. Clinical features, high-resolution computed tomography, and surgical lung biopsies were each examined independently using a prespecified approach. This was followed by a multidisciplinary discussion in which the likelihood of an idiopathic pulmonary fibrosis diagnosis was assigned by the clinician alone based only on clinical data, by the clinician and radiologist based on integrated clinical and radiologic data, and by the clinician, radiologist, and pathologist based on all three domains. A higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis was associated with older age at diagnosis, male sex, higher forced vital capacity, and absence of ground glass changes. Pathologic variables associated with a higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis included increased number of fibroblast foci/cm

Introduction Coronary artery calcification is a significant contributor to reduced accuracy of coronary computed tomographic angiography (CTA) in the assessment of coronary artery disease severity. The aim of the current study is to assess the impact of a prototype calcium deblooming algorithm on the diagnostic accuracy of CTA. Methods 40 patients referred for invasive catheter angiography underwent CTA and invasive catheter angiography. CTA studies were read with and without the deblooming algorithm blinded to the invasive coronary angiogram findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value for the detection of stenosis ≥50% were evaluated using quantitative coronary angiography as the reference standard. Results All studies were diagnostic with 581 segments available for evaluation. Image score was 3.64±0.72 with CTADEBLOOM, versus 3.56±0.72 with CTASTAND (p=0.38). CTADEBLOOM had significantly less calcium blooming artifact than CTASTAND (12.5% vs. 47.5%, p=0.001). The Sensitivity/Specificity/PPV/NPV/Accuracy were 64.4/85.2/27.6/96.5/83.5 for CTADEBLOOM and 75.0/81.6/25.8/97.5/81.1 for CTASTAND. CTADEBLOOM specificity was significantly higher than CTASTAND (85.2% vs. 81.6%, p=0.017), with no difference between the algorithms in sensitivity (p=0.22), or accuracy (p= 0.09). Interobserver agreement was fair with both techniques (CTADEBLOOMk= 0.38, CTASTAND k= 0.37). Conclusion Coronary calcification deblooming using a prototype post-processing algorithm is feasible and significantly reduces calcium blooming with an improvement of the specificity of the CTA exam.

Background Total kidney volume (TKV) assessment is valuable in autosomal dominant polycystic kidney disease (ADPKD) but the reference standard method of MRI planimetry requires access to MRI and time-consuming interpretation. Purpose To determine whether accurate TKV measurements comparable to the resource-intensive reference standard of MRI planimetry can be obtained by using alternate methods including dose-reducing CT protocols and time-saving measurement equations. Materials and Methods In this prospective study conducted September 2016 to June 2017, adult participants with ADPKD underwent one MRI and two CT examinations. Low-dose (LD) and ultra-low-dose (ULD) CT examinations were performed with radiation doses 1.4 and 2.6 times lower, respectively, than the authors' institution's standard abdomen and pelvis CT. ULD CT examinations were reconstructed via model-based iterative reconstruction. Three TKV measurement equations were applied to all image sets, and MRI manual planimetry was the reference standard. Spearman correlation with the reference standard, simple linear regression, and root mean square error (RMSE) calculation analyzed accuracy of these methods; intraclass correlation coefficient examined reproducibility. Results Thirty participants (mean age, 41 years; age range, 24-67 years) had a mean TKV of 1368.9 mL ± 1146.13 (standard deviation). The ULD and LD CT protocols had median dose-length product of 58.8 and 115.5 mGy ∙ cm, respectively (P = .01), and CT dose index of 1.2 and 3.9 mGy, respectively (P 0.98). RMSE ranged from 80.5 to 157.3 mL (5.9%-11.5% of mean TKV). Intraclass correlation coefficients were greater than 0.98 for all methods. Mean measurement times for the ellipsoid method ranged from 4.6 to 5.2 minutes compared with a mean of 27.7 minutes (range, 14-60 minutes) for manual planimetry. Conclusion Accurate and reproducible total kidney volume measurements comparable to the reference standard of MRI planimetry can be obtained by using a dose-minimizing ultra-low-dose CT protocol and volume measurement based on discrete linear measurements. © RSNA, 2019 Online supplemental material is available for this article.

Nawaf M Alotaibi,1,2 Virginia Chen,1,3,4 Zsuzsanna Hollander,1,3,4 Jonathon A Leipsic,5 Cameron J Hague,5 Darra T Murphy,5 Mari L DeMarco,1,6 JM FitzGerald,3,7,8 Bruce M McManus,1,3,4,6 Raymond T Ng,4,9 Don D Sin1,3,7 1Centre for Heart Lung Innovation, James Hogg Research Centre, St Paul’s Hospital, Vancouver, BC, Canada; 2Department of Medicine, Division of Pulmonary Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia; 3Institute for Heart and Lung Health, Vancouver, BC, Canada; 4PROOF Centre of Excellence, Vancouver, BC, Canada; 5Department of Radiology, St Paul’s Hospital, Vancouver, BC, Canada; 6Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada; 7Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, BC, Canada; 8The Lung Centre, Vancouver General Hospital, Vancouver, BC, Canada; 9Department of Computer Sciences, University of British Columbia, Vancouver, BC, Canada Background: Etiologies of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are heterogeneous. We phenotyped severe AECOPD based on molecular pathogen detection of sputum samples collected at hospitalization of COPD patients and determined their outcomes.Methods: We phenotyped 72 sputum samples of COPD patients who were hospitalized with a primary diagnosis of AECOPD using a molecular array that detected common bacterial and viral respiratory pathogens. Based on these results, the patients were classified into positive or negative pathogen groups. The pathogen-positive group was further divided into virus or bacteria subgroups. Admission day 1 blood samples were assayed for N-terminal prohormone brain natriuretic peptide, CRP, and complete blood counts.Results: A total of 52 patients had a positive result on the array, while 20 patients had no pathogens detected. The most common bacterial pathogen detected was Haemophilus influenzae and the most common virus was rhinovirus. The pathogen-negative group had the worse outcomes with longer hospital stays (median 6.5 vs 5 days for bacteria-positive group, P=0.02) and a trend toward increased 1-year mortality (P=0.052). The bacteria-positive group had the best prognosis, whereas the virus-positive group had outcomes somewhere in between the bacteria-positive and pathogen-negative groups.Conclusion: Molecular diagnostics on sputum can rapidly phenotype serious AECOPD into bacteria-, virus-, or pathogen-negative groups. The bacteria-positive group appears to have the best prognosis, while pathogen-negative group has the worst. These data suggest that AECOPD is a heterogeneous event and that accurate phenotyping of AECOPD may lead to novel management strategies that are personalized and more precise. Keywords: COPD, molecular pathogen detection, exacerbation phenotypes