Evaluation of interstitial lung disease: An algorithmic review using ILD-RADS.

Interstitial lung diseases (ILDs) may present a diagnostic dilemma due to their many classifications and overlapping imaging findings. In this review, we present an algorithmic approach for assessing ILDs based on identifying and understanding key imaging features to aid in narrowing a differential diagnosis or reaching a specific diagnosis. We use the recently introduced Interstitial Lung Disease Reporting And Data System (ILD-RADS) as a framework for our discussion.

COVID-19 pneumonia chest radiographic severity score: variability assessment among experienced and in-training radiologists and creation of a multireader composite score database for artificial intelligence algorithm development.

OBJECTIVE: The purpose was to evaluate reader variability between experienced and in-training radiologists of COVID-19 pneumonia severity on chest radiograph (CXR), and to create a multireader database suitable for AI development. METHODS: In this study, CXRs from polymerase chain reaction positive COVID-19 patients were reviewed. Six experienced cardiothoracic radiologists and two residents classified each CXR according to severity. One radiologist performed the classification twice to assess intraobserver variability. Severity classification was assessed using a 4-class system: normal (0), mild (1), moderate (2), and severe (3). A median severity score (Rad Med) for each CXR was determined for the six radiologists for development of a multireader database (XCOMS). Kendal Tau correlation and percentage of disagreement were calculated to assess variability. RESULTS: A total of 397 patients (1208 CXRs) were included (mean age, 60 years SD ± 1), 189 men). Interobserver variability between the radiologists ranges between 0.67 and 0.78. Compared to the Rad Med score, the radiologists show good correlation between 0.79-0.88. Residents show slightly lower interobserver agreement of 0.66 with each other and between 0.69 and 0.71 with experienced radiologists. Intraobserver agreement was high with a correlation coefficient of 0.77. In 220 (18%), 707 (59%), 259 (21%) and 22 (2%) CXRs there was a 0, 1, 2 or 3 class-difference. In 594 (50%) CXRs the median scores of the residents and the radiologists were similar, in 578 (48%) and 36 (3%) CXRs there was a 1 and 2 class-difference. CONCLUSION: Experienced and in-training radiologists demonstrate good inter- and intraobserver agreement in COVID-19 pneumonia severity classification. A higher percentage of disagreement was observed in moderate cases, which may affect training of AI algorithms. ADVANCES IN KNOWLEDGE: Most AI algorithms are trained on data labeled by a single expert. This study shows that for COVID-19 X-ray severity classification there is significant variability and disagreement between radiologist and between residents.

CT Morphologic Characteristics and Variant Patterns of Interstitial Pulmonary Fibrosis in Systemic Lupus Erythematosus.

PURPOSE: To assess CT features of pulmonary fibrosis in patients with systemic lupus erythematosus (SLE) and to assess the presence of several distinctive patterns of fibrosis associated with connective tissue disease. MATERIALS AND METHODS: A cross-sectional retrospective analysis was performed. An institutional clinical database was queried for the years of 2005-2015 to identify CT examination reports of patients with SLE and fibrotic lung disease, which yielded 50 patients (median age, 49 years; age range, 22-71 years; 46 women). CT examination reports were scored by two subspecialty thoracic radiologists using a standard multilevel semiquantitative system. Readers noted the presence or absence of several recently described CT signs of variant patterns of fibrosis in connective tissue disease (the "anterior upper lobe," "straight-edge," and "exuberant honeycombing" signs), as well as two other morphologic characteristics (an "island-like" appearance of areas of well-defined fibrosis with angular margins surrounded by normal lung and confluent regions of lucent lung destruction). RESULTS: The most common CT patterns were characterized as either fibrotic nonspecific interstitial pneumonia (38%, 19 of 50) or variant fibrosis (44%, 22 of 50). CT signs of variant fibrosis were identified by both readers in up to 62% of patients, with good κ agreement (0.44-0.64); the island-like sign (62%) and anterior upper lobe sign (52%) were most commonly observed. Pulmonary function test results showed correlations with several imaging findings but did not show correlations with CT signs of variant fibrosis. CONCLUSION: When present, pulmonary fibrosis in SLE often has a distinctive appearance and may also manifest as several variant fibrotic patterns.Keywords: CT, Lung© RSNA, 2021See also the commentary by White in this issue.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Imaging and Clinical Features of a Frequently Delayed Diagnosis.

OBJECTIVE. The purpose of this study was to assess features of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) on CT, clinical presentation, and delays in radiologic and clinical diagnosis in a series of 32 patients. MATERIALS AND METHODS. Medical records of patients with DIPNECH from the years 2000-2017 were obtained from an institutional data warehouse. Inclusion criteria were an available CT examination and either a pathologic diagnosis of DIPNECH or pathologic findings of multiple carcinoid tumorlets or carcinoid tumor with CT features suggesting DIPNECH. Two thoracic radiologists with 10 and 14 years of experience reviewed CT examinations and scored cases in consensus. RESULTS. All 32 patients were women, and most had never smoked (69%). The mean age at presentation was 61 years. Symptoms included chronic cough (59%) or dyspnea (28%), and the initial clinical diagnosis was asthma in 41%. DIPNECH was clinically suspected at presentation in only one case and was mentioned by the interpreting radiologist in only 31% of cases. CT characteristics included numerous nodules with a lower zone and peribronchiolar predominance, mosaic attenuation, and nodular bronchial wall thickening. Number of nodules at least 5 mm in diameter showed strong inverse correlations with the percentage predicted for both forced vital capacity and forced expiratory volume in 1 second and a moderate inverse correlation with total lung capacity percentage predicted. In cases with a follow-up CT interval of 3 years or longer, 85% of patients showed an increase in size of the largest nodule, and 70% had an increase in size in multiple nodules. CONCLUSION. Many cases of DIPNECH are originally missed or misdiagnosed by radiologists and clinicians. Awareness of the typical clinical and imaging features of DIPNECH may prompt earlier diagnosis of this condition.

Reducing STAT Portable Chest Radiograph Turnaround Times: A Pilot Study.

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

Mediastinal and Hilar Lymph Node Measurements. Comparison of Multidetector-Row Computed Tomography and Endobronchial Ultrasound.

RATIONALE: Multidetector-row chest computed tomography scan is a common initial imaging modality and endobronchial ultrasound is a minimally invasive diagnostic tool used to evaluate enlarged lymph nodes, but comparisons of imaging results are lacking. OBJECTIVES: To determine the size of thoracic lymph nodes and the strength of agreement between each measurement from coronal plane computed tomography and static endobronchial ultrasound images. METHODS: A retrospective review of consecutive patients who underwent endobronchial ultrasound-transbronchial needle aspiration of their lymph nodes because of clinical suspicion of benign or malignant thoracic disease. MEASUREMENTS AND MAIN RESULTS: One hundred and twenty-four lymph nodes from the mediastinal (74.2%) and hilar (25.8%) stations were measured in 59 patients (mean age, 64.5 yr; 33 males). The mean (standard deviation) short-axis diameter on computed tomography was 14.1 (6.7) mm compared with 12.6 (6.6) mm on endobronchial ultrasound. Benign lymph nodes (n = 42) were larger on computed tomography than on endobronchial ultrasound (14.1 [6.2] vs. 11.5 [6.2] mm). Malignant lymph nodes (n = 35) were larger on endobronchial ultrasound than on computed tomography (17.3 [6.4] vs. 16.2 [6.7] mm). Sixty-five percent of the lymph nodes that were initially interpreted as not enlarged on axial computed tomography images measured greater than 10 mm on each imaging modality (12.5 [5.9] mm on computed tomography and 10.5 [5.6] mm on endobronchial ultrasound) and 24% of the sampled lymph nodes from this group contained malignant cells. Random-effects maximal likelihood linear regression showed a statistically significant difference between endobronchial ultrasound and the computed tomography method for measuring short-axis diameter in all 124 lymph nodes. There was a weak agreement (intraclass correlation, rho: 0.44 [95% confidence interval, 0.31-0.59]) between short-axis diameter measurements from each imaging modality. CONCLUSIONS: Our single-center study shows that there was poor correlation between computed tomography and endobronchial ultrasound for the measurement of mediastinal and hilar lymph nodes. Malignant cells were recovered by ultrasound-guided needle aspiration from a substantial fraction of lymph nodes that were initially interpreted as normal in size. If these findings are confirmed, new criteria may be needed for lymph node measurement on computed tomography that will guide selection of lymph nodes for endobronchial ultrasound-transbronchial needle aspiration.

Pulmonary effects of synthetic marijuana: chest radiography and CT findings.

OBJECTIVE: The purpose of this article is to present the first chest radiographic and CT descriptions of organizing pneumonia in response to smoking synthetic marijuana. CONCLUSION: Chest radiographs showed a diffuse miliary-micronodular pattern. Chest CT images showed diffuse centrilobular nodules and tree-in-bud pattern and a histopathologic pattern of organizing pneumonia with or without patchy acute alveolar damage. This distinct imaging pattern should alert radiologists to include synthetic marijuana abuse in the differential diagnosis.

Lung CT: Part 2, The interstitial pneumonias--clinical, histologic, and CT manifestations.

OBJECTIVE: The interstitial pneumonias are a group of heterogeneous nonneoplastic lung diseases that may be idiopathic or associated with an underlying abnormality. Although they share some features in common, they also exhibit diverse pulmonary manifestations. Imaging plays an essential role in characterizing this group of disorders and can often suggest the diagnosis, though the final interpretation requires a coordinated effort involving the radiologist, pathologist, and clinician. The purpose of this article is to review the imaging features of the interstitial pneumonias according to their histologic patterns and to provide a brief overview of their clinical presentations. CONCLUSION: This article reviews the interstitial pneumonias according to their histologic subtypes, including both idiopathic and secondary forms. On completion, the reader should have an improved understanding of the classification of the interstitial pneumonias, associated causes, characteristic imaging features, histologic descriptions, clinical manifestations, and prognoses.

A combined pulmonary-radiology workshop for visual evaluation of COPD: study design, chest CT findings and concordance with quantitative evaluation.

UNLABELLED: The purposes of this study were: to describe chest CT findings in normal non-smoking controls and cigarette smokers with and without COPD; to compare the prevalence of CT abnormalities with severity of COPD; and to evaluate concordance between visual and quantitative chest CT (QCT) scoring. METHODS: Volumetric inspiratory and expiratory CT scans of 294 subjects, including normal non-smokers, smokers without COPD, and smokers with GOLD Stage I-IV COPD, were scored at a multi-reader workshop using a standardized worksheet. There were 58 observers (33 pulmonologists, 25 radiologists); each scan was scored by 9-11 observers. Interobserver agreement was calculated using kappa statistic. Median score of visual observations was compared with QCT measurements. RESULTS: Interobserver agreement was moderate for the presence or absence of emphysema and for the presence of panlobular emphysema; fair for the presence of centrilobular, paraseptal, and bullous emphysema subtypes and for the presence of bronchial wall thickening; and poor for gas trapping, centrilobular nodularity, mosaic attenuation, and bronchial dilation. Agreement was similar for radiologists and pulmonologists. The prevalence on CT readings of most abnormalities (e.g. emphysema, bronchial wall thickening, mosaic attenuation, expiratory gas trapping) increased significantly with greater COPD severity, while the prevalence of centrilobular nodularity decreased. Concordances between visual scoring and quantitative scoring of emphysema, gas trapping and airway wall thickening were 75%, 87% and 65%, respectively. CONCLUSIONS: Despite substantial inter-observer variation, visual assessment of chest CT scans in cigarette smokers provides information regarding lung disease severity; visual scoring may be complementary to quantitative evaluation.