DIPNECH: when to suggest this diagnosis on CT.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is an under-recognized disease characterized by proliferation of neuroendocrine cells in the bronchial wall. It is considered a pre-invasive lesion for lung carcinoid tumours and is found in 5.4% of patients undergoing surgical resection for lung carcinoid tumours. Other manifestations of DIPNECH include bronchial obstruction and formation of tumorlets. DIPNECH preferentially affects middle-aged women. Patients are either asymptomatic or present with long-standing dyspnoea due to obstructive syndrome that can be mistaken for asthma. At CT, mosaic attenuation with multiple small nodules is very suggestive of DIPNECH. The aim of this review is to describe DIPNECH-related CT features and correlate them with histology, in order to help radiologists suggest this diagnosis and distinguish DIPNECH from other causes of mosaic perfusion.

Radiological assessment after stereotactic body radiation of lung tumours.

The increasing use of stereotactic body radiation therapy for lung tumours comes along with new post-therapeutic imaging findings that should be known by physicians involved in patient follow-up. Radiation-induced lung injury is much more frequent than after conventional radiation therapy, it can also be delayed and has a different radiological presentation. Radiation-induced lung injury after stereotactic body radiation therapy involves the lung parenchyma surrounding the target tumour and appears as a dynamic process continuing for years after completion of the treatment. Thus, the radiological pattern and the severity of radiation-induced lung injury are prone to changes during follow-up, which can make it difficult to differentiate from local recurrence. Contrary to radiation-induced lung injury, local recurrence after stereotactic body radiation therapy is rare. Other complications mainly depend on tumour location and include airway complications, rib fractures and organizing pneumonia. The aim of this article is to provide a wide overview of radiological changes occurring after SBRT for lung tumours. Awareness of changes following stereotactic body radiation therapy should help avoiding unnecessary interventions for pseudo tumoral presentations.

Optimization of acquisition parameters for reduced-dose thoracic CT: A phantom study.

PURPOSE: The purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine. MATERIALS AND METHODS: Using an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDIvol]=0.15, 0.20, 0.30 and 0.40mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDIvol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale. RESULTS: Best visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30mGy was not associated with a significant decrease in visual scores (P<0.05), however decreasing radiation dose from 0.30mGy to 0.15mGy was associated with a lower visibility of most of the evaluated structures (P<0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly. CONCLUSION: Favoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.

COVID-19 pneumonia: A review of typical CT findings and differential diagnosis.

The standard of reference for confirming COVID-19 relies on microbiological tests such as real-time polymerase chain reaction (RT-PCR) or sequencing. However, these tests might not be available in an emergency setting. Computed tomography (CT) can be used as an important complement for the diagnosis of COVID-19 pneumonia in the current epidemic context. In this review, we present the typical CT features of COVID-19 pneumonia and discuss the main differential diagnosis.

Nodular reverse halo sign in active pulmonary tuberculosis: A rare CT feature?

PURPOSE: The purpose of this study was to investigate the prevalence of the nodular reverse halo sign (NRHS) in chest computed tomography (CT) in patients with active pulmonary tuberculosis. MATERIALS AND METHODS: From March 2018 to March 2019, 29 consecutive patients with a culture-confirmed active pulmonary tuberculosis and who underwent chest CT examination during hospital-admission were retrospectively included in the study. There were 24 men and 5 women with a mean age of 40.9±16.7 (SD) years (range: 18-80years). Chest CT examinations of included patients were evaluated for the presence of NRHS and other tuberculosis-related CT signs. RESULTS: CT revealed the NRHS in 5 patients (5/29; 17%). The other CT signs of tuberculosis included consolidations in 18 patients (18/29; 62%), tree-in-bud pattern in 14 patients (14/29; 48%), cavitation in 12 patients (12/29; 41%), sparse nodules in 10 patients (10/29; 34%), and pleural effusion in 8 patients (8/29; 28%). CONCLUSION: CT shows NRHS in 17% of patients with active pulmonary tuberculosis, indicating that the sign is not as rare as previously thought in patients with this condition.

Incidental diagnosis of Covid-19 pneumonia on chest computed tomography.

PURPOSE: The purpose of this study was to determine the prevalence and imaging characteristics of incidentally diagnosed COVID-19 pneumonia on computed tomography (CT). MATERIALS AND METHODS: This retrospective study was conducted between March 20th and March 31st, 2020 at Cochin hospital, Paris France. Thoracic CT examinations of all patients referred for another reason than a suspicion of SARS-CoV-2 infection were reviewed. CT images were analyzed by a chest radiologist to confirm the presence of findings consistent with COVID-19 pneumonia and quantify disease extent. Clinical and biological data (C-reactive protein serum level [CRP] and white blood cell count) of patients with CT findings suggestive for COVID-19 pneumonia were retrieved from the electronic medical chart. RESULTS: During the study period, among 205 diagnostic CT examinations, six examinations (6/205, 3%) in 6 different patients (4 men, 2 women; median age, 57 years) revealed images highly suggestive of COVID-19 pneumonia. The final diagnosis was confirmed by RT-PCR. Three inpatients were suspected of extra thoracic infection whereas three outpatients were either fully asymptomatic or presented with fatigue only. All had increased CRP serum level and lymphopenia. Disease extent on CT was mild to moderate in 5/6 patients (83%) and severe in 1/6 patient (17%). CONCLUSION: Cumulative incidence of fortuitous diagnosis if COVID-19 pneumonia did not exceed 3% during the highest pandemic phase and was predominantly associated with limited lung involvement.

Artificial intelligence solution to classify pulmonary nodules on CT.

PURPOSE: The purpose of this study was to create an algorithm to detect and classify pulmonary nodules in two categories based on their volume greater than 100 mm3 or not, using machine learning and deep learning techniques. MATERIALS AND METHOD: The dataset used to train the model was provided by the organization team of the SFR (French Radiological Society) Data Challenge 2019. An asynchronous and parallel 3-stages pipeline was developed to process all the data (a data "pre-processing" stage; a "nodule detection" stage; a "classifier" stage). Lung segmentation was achieved using 3D U-NET algorithm; nodule detection was done using 3D Retina-UNET and classifier stage with a support vector machine algorithm on selected features. Performances were assessed using area under receiver operating characteristics curve (AUROC). RESULTS: The pipeline showed good performance for pathological nodule detection and patient diagnosis. With the preparation dataset, an AUROC of 0.9058 (95% confidence interval [CI]: 0.8746-0.9362) was obtained, 87% yielding accuracy (95% CI: 84.83%-91.03%) for the "nodule detection" stage, corresponding to 86% specificity (95% CI: 82%-92%) and 89% sensitivity (95% CI: 84.83%-91.03%). CONCLUSION: A fully functional pipeline using 3D U-NET, 3D Retina-UNET and classifier stage with a support vector machine algorithm was developed, resulting in high capabilities for pulmonary nodule classification.

Three artificial intelligence data challenges based on CT and MRI.

PURPOSE: The second edition of the artificial intelligence (AI) data challenge was organized by the French Society of Radiology with the aim to: (i), work on relevant public health issues; (ii), build large, multicentre, high quality databases; and (iii), include three-dimensional (3D) information and prognostic questions. MATERIALS AND METHODS: Relevant clinical questions were proposed by French subspecialty colleges of radiology. Their feasibility was assessed by experts in the field of AI. A dedicated platform was set up for inclusion centers to safely upload their anonymized examinations in compliance with general data protection regulation. The quality of the database was checked by experts weekly with annotations performed by radiologists. Multidisciplinary teams competed between September 11th and October 13th 2019. RESULTS: Three questions were selected using different imaging and evaluation modalities, including: pulmonary nodule detection and classification from 3D computed tomography (CT), prediction of expanded disability status scale in multiple sclerosis using 3D magnetic resonance imaging (MRI) and segmentation of muscular surface for sarcopenia estimation from two-dimensional CT. A total of 4347 examinations were gathered of which only 6% were excluded. Three independent databases from 24 individual centers were created. A total of 143 participants were split into 20 multidisciplinary teams. CONCLUSION: Three data challenges with over 1200 general data protection regulation compliant CT or MRI examinations each were organized. Future challenges should be made with more complex situations combining histopathological or genetic information to resemble real life situations faced by radiologists in routine practice.

Cumulative radiation dose after lung transplantation in patients with cystic fibrosis.

PURPOSE: The purpose of this study was first to evaluate the imaging-related cumulative post-transplantation radiation dose in cystic fibrosis (CF) lung transplantation (LT) recipients and second, to identify the occurrence and type of malignancies observed after LT. MATERIALS AND METHODS: A total of 52 patients with CF who underwent LT at our institution between January 2001 and December 2006 with at least 3 years of survival were retrospectively included. There were 27 men and 25 women with a mean age of 24.4±9.2 (SD) years (range: 7.6-52.9 years) at the time of LT. Calculation of cumulative effective and organ doses after LT were based on dosimetry information and acquisition parameters of each examination. Cumulative radiation doses were calculated until June 2016, but stopped at the time of de novomalignancy diagnosis, for patients developing the condition. RESULTS: Patients received a mean cumulative effective dose of 110.0±51.6 (SD) mSv (range: 13-261.3 mSv) over a mean follow-up of 8.1±3.6 (SD) years (range: 0.5-13.5 years), with more than 100mSv in 5 years in 19/52 patients (37%). Chest CT accounted for 73% of the cumulative effective dose. Mean doses to the lung, breast and thyroid were 152.8±61.1 (SD) mGy (range: 21.2-331.6 mGy), 106.5±43.2 (SD) mGy (range: 11.9-221.4 mGy) and 72.7±31.8 (SD) mGy (range: 9.5-165.0 mGy), respectively. Nine out of 52 patients (17%) developed a total of 10 de novo malignancies, all but one attributable to immunosuppression after a mean post-transplantation follow-up period of 11.1±3.5 (SD) years (range: 3.7-16.3 years). Six-month cumulative effective dose was not greater in patients with de novomalignancies than in those without de novomalignancies (28.9±14.5 (SD) mGy (range: 13.0-53.4) vs 25.6±15.3 (range: 5.0-69.7), respectively, P>0.05). CONCLUSION: The cumulative effective dose exceeded 100 mSv in 5 years in 37% of LT recipients, the reason why continuous efforts should be made to optimize chest CT acquisitions accounting for 73% of the radiation dose.

Combined pulmonary fibrosis and emphysema in systemic sclerosis: A syndrome associated with heavy morbidity and mortality.

BACKGROUND: The syndrome of combined pulmonary fibrosis and emphysema (CPFE) primarily due to tobacco smoking has been reported in connective tissue disease, but little is known about its characteristics in systemic sclerosis (SSc). METHODS: In this retrospective multi-center case-control study, we identified 36 SSc patients with CPFE, and compared them with 72 SSc controls with interstitial lung disease (ILD) without emphysema. RESULTS: Rate of CPFE in SSc patients with CT scan was 3.6%, and 7.6% among SSc patients with ILD. CPFE-SSc patients were more likely to be male (75 % vs 18%, p < 0.0001), smokers (83 % vs 33%, p < 0.0001), and to have limited cutaneous SSc (53 % vs 24% p < 0.01) than ILD-SSc controls. No specific autoantibody was significantly associated with CPFE. At diagnosis, CPFE-SSc patients had a greater decrease in carbon monoxide diffusing capacity (DLCO 39 ± 13 % vs 51 ± 12% of predicted value, p < 0.0001) when compared to SSc-ILD controls, whereas lung volumes (total lung capacity and forced vital capacity) were similar. During follow-up, CPFE-SSc patients more frequently developed precapillary pulmonary hypertension (PH) (44 % vs 11%, p < 10-4), experienced more frequent unscheduled hospitalizations (50 % vs 25%, p < 0.01), and had decreased survival (p < 0.02 by Kaplan-Meier survival analysis) as compared to ILD-SSc controls. CONCLUSIONS: The CPFE syndrome is a distinct pulmonary manifestation in SSc, with higher morbidity and mortality. Early diagnosis of CPFE by chest CT in SSc patients (especially smokers) may result in earlier smoking cessation, screening for PH, and appropriate management.

[Bronchiectasis in adults: Etiological diagnosis]. / Diagnostic étiologique d'une dilatation des bronches.

Bronchiectasis is defined by a permanent and irreversible increase in airway caliber. Computed tomography (CT) scan is required for diagnosis and allows differentiating localized (affecting only one lobe) from diffuse (affecting two or more lobes) bronchiectasis. Localized bronchiectasis is usually related to a local cause (e.g., tumor, compression by lymph nodes, foreign body) whereas there are multiple causes of diffuse bronchiectasis. Main causes of diffuse bronchiectasis can be grouped into 5 categories: (1) immune deficiencies; (2) genetic disorders responsible for abnormal mucociliairy clearance (e.g., cystic fibrosis and primary ciliary dyskinesia); (3) autoinflammatory and connective tissue diseases (e.g., rheumatoid arthritis, Sjogren syndrome); (4) chronic airway inflammatory disorders (e.g., allergic broncho-pulmonary aspergillosis) or chronic infections (e.g., by nontuberculous mycobacteria) and; (5) sequelae of pulmonary insults (e.g., infection, radiotherapy). In the absence of a specific cause, bronchiectasis are called idiopathic. Bronchoscopy is the cornerstone for etiological diagnosis in localized bronchiectasis. Investigation of diffuse bronchiectasis includes standardized biological tests, eventually completed by specialized explorations (e.g., analysis of epithelial ion transport and/or ciliary beating). After this systematic approach, an etiological diagnosis is obtained in approximately 60% of cases, often resulting in therapeutic consequences and in some cases in genetic counselling.

[Acute pulmonary and non-pulmonary complications in adults with cystic fibrosis]. / Complications aiguës respiratoires et non respiratoires chez l'adulte mucoviscidosique.

INTRODUCTION: Cystic fibrosis (CF) is a genetic disease primarily affecting the lungs, which could lead to chronic respiratory failure and premature death. CF patients are usually followed in specialized centers, but may present outside of these centers when they seek care for acute pulmonary and/or non-pulmonary complications. The aim of this paper is to provide appropriate knowledge necessary for managing respiratory and non-respiratory emergencies in CF adults. METHODS: The review is based on international guidelines, extensive search of the available literature using Pubmed, and experience of the CF reference center at Cochin hospital (Paris, France). Complications occurring after solid organ transplantation (e.g., lung and/or liver) are excluded from this review. RESULTS: Main acute respiratory complications are pulmonary exacerbations, hemoptysis, pneumothorax and allergic bronchopulmonary aspergillosis. Acute non-respiratory complications include hyponatremic dehydration, acute pancreatitis, acute complications of gallstones, distal intestinal obstruction syndrome, symptomatic nephrolithiasis, acute kidney injury, drug intolerances and catheter-related acute complications. CONCLUSION: This review summarizes acute pulmonary and non-pulmonary complications occurring in adults with CF, focusing on diagnosis and principles of treatment, with the aim of providing a reference that can be used in clinical practice.

[Ageing with cystic fibrosis: Classical and emerging comorbidities in adults with cystic fibrosis]. / Vieillir avec la mucoviscidose : comorbidités classiques et émergentes chez l'adulte mucoviscidosique.

Cystic fibrosis (CF) is a genetic disease with pulmonary involvement being predominant and often leading to respiratory failure and premature death. Non-pulmonary complications related to CF transmembrane conductance regulator (CFTR) defect are numerous and account for significant morbidity (exocrine pancreatic insufficiency, diabetes, CF-related liver disease, chronic sinusitis, osteoporosis). Improvement in patients' care led to a continuous increase in life expectancy, with a subsequent increase in the number of adult CF patients worldwide. Increased life expectancy comes with increased prevalence of CF-related comorbidities, but also with new emerging complications directly related to ageing (chronic kidney disease, cardiovascular risk factors, cancers). CFTR modulators might also contribute to modify the face of CF epidemiology and prognosis. Ageing with CF has become a challenge for CF patients and caregivers. This review summarizes classic and emerging comorbidities in the context of current growth and ageing of the CF population. It also addresses potential roles of CFTR modulators.

[Bronchiectasis imaging]. / Imagerie des dilatations des bronches.

Bronchiectasis are defined as an irreversible focal or diffuse dilatation of the bronchi and can be associated with significant morbidity. The prevalence is currently increasing, probably due to an increased use of thoracic computed tomography (CT). Indeed, the diagnosis relies on imaging and chest CT is the gold standard technique. The main diagnosis criterion is an increased bronchial diameter as compared to that of the companion artery. However, false positives are possible when the artery diameter is decreased, which is called pseudo-bronchiectasis. Other features such as the lack of bronchial tapering, and visibility of bronchi within 1cm of the pleural surface are also diagnostic criteria, and other CT features of bronchial disease are commonly seen. Thoracic imaging also allows severity assessment and long-term monitoring of structural abnormalities. The distribution pattern and the presence of associated findings on chest CT help identifying specific causes of bronchiectasis. Lung MRI and ultra-low dose CT and are promising imaging modalities that may play a role in the future. The objectives of this review are to describe imaging features for the diagnosis and severity assessment of bronchiectasis, to review findings suggesting the cause of bronchiectasis, and to present the new developments in bronchiectasis imaging.

[New TNM classification of non-small cell lung cancer]. / Nouvelle classification TNM des cancers du poumon non à petites cellules.

Initial staging is a key part of the initial evaluation of non-small cell lung cancer. It relies on the 7th edition of the TNM classification. Proposals have been recently developed for the 8th edition of the classification, which is due to be enacted in early 2017. Among these proposals, the weight of tumor size has been increased and new N descriptors have been introduced to further describe N category depending on the number station involved. Regarding M descriptors, oligometastatic disease is distinguished from multiple distant extrathoracic metastases.

Lung cancer screening: Current status and perspective.

Lung cancer screening by low-dose computed tomography (CT) has been proven to reduce lung cancer-related mortality by 20%, in the National Lung cancer Screening Trial (NLST). Low-dose CT acquisition protocols should result in effective dose not exceeding 1.5mSv, and should be read by radiologists who have an expertise in the field. A volumetry-based approach similar to that used in the NELSON study allows reducing the rate of positive screens around 2%. The major harm of screening is overdiagnosis, which correspond to the detection of indolent tumours that would not cause the subject death. Ongoing research for the development of useful biomarkers to be combined to imaging could improve the accuracy of lung cancer screening.

[Computed tomography imaging of non-small cell lung cancer]. / Imagerie par tomodensitométrie du cancer bronchique non à petites cellules.

Computed tomography (CT) plays a key role in the initial evaluation of non-small cell lung cancer. It allows initial staging and helps targeting lesions for pathological analysis. The aim of initial imaging work-up is to differentiate between localized disease, eligible to a local treatment, and advanced disease requiring medical treatment. CT is very useful for the assessment of local extension but is less accurate than positron emission tomography (PET)-CT for the assessment of lymphatic and metastatic spread. However, initial staging should include CT examination of the brain and upper abdomen, and PET-CT should be only be performed in patients eligible to a local treatment after initial CT assessment. Propositions for the 8th edition of lung cancer TNM bring several changes for T staging. In particular, the weight of lesion size is increased. Similarly, N1 and N2 stages are now divided in subgroups according the number of involved stations.

Academic productivity of French radiology residents: Where do we stand?

RATIONALE AND OBJECTIVES: Although medical research by French radiology residents is encouraged, their publication productivity remains unknown. Thus, we aimed to assess and analyze the publication rate of medical theses and the overall academic productivity of radiology residents who graduated in 2009 and 2010. MATERIALS AND METHODS: The list of radiology residents and imaging theses were obtained from the French internet database of university theses. The main characteristics of the theses were recorded and correlated with associated publications identified by scanning the PubMed database. All other publications by French radiology residents not related to the theses were also obtained, described and compared to published theses. RESULTS: Seventy-nine out of 224 (35.3%) medical theses written by French radiology residents in 2009 and 2010 were transformed into articles published in Medline-indexed journals. Residents were first authors in 69% (60/87) of these articles. The factors associated with publication of the thesis were a prospective design (P=0.01) and the publication as a first author of an original study not related to the thesis (P=0.01). Seventy-one percent of the residents had published at least one other article, including 36.6% as first authors. CONCLUSION: Academic productivity of French radiology residents is high thanks to published theses and other articles.