Overview of positron emission tomography in functional imaging of the lungs for diffuse lung diseases

Positron emission tomography (PET) is a quantitative molecular imaging modality increasingly used to study pulmonary disease processes and drug effects on those processes. The wide range of drugs and other entities that can be radiolabeled to study molecularly targeted processes is a major strength of PET, thus providing a noninvasive approach for obtaining molecular phenotyping information. The use of PET to monitor disease progression and treatment outcomes in DLD has been limited in clinical practice, with most of such applications occurring in the context of research investigations under clinical trials. Given the high costs and failure rates for lung drug development efforts, molecular imaging lung biomarkers are needed not only to aid these efforts but also to improve clinical characterization of these diseases beyond canonical anatomic classifications based on computed tomography. The purpose of this review article is to provide an overview of PET applications in characterizing lung disease, focusing on novel tracers that are in clinical development for DLD molecular phenotyping, and briefly address considerations for accurately quantifying lung PET signals.

Anticoagulant Use as an Independent Risk Factor and Higher In-Hospital Mortality in Patients Showing Alveolar Hemorrhage in Diffuse Lung Disease

Background and objectives: Bronchoalveolar lavage (BAL) is commonly performed to evaluate diffuse lung disease and occasionally to identify alveolar hemorrhage. However, the clinical impact of alveolar hemorrhage and its risk factors in patients with diffuse lung disease have not been clarified. Materials and Methods: We retrospectively analyzed the medical records of all patients who underwent BAL to evaluate diffuse lung disease from January 2017 to December 2020. Alveolar hemorrhage was defined as progressive hemorrhagic BAL fluid or the presence of ≥20% hemosiderin-laden macrophages in the BAL fluid. Logistic regression analysis was performed to assess the association between alveolar hemorrhage and other factors. Results: Sixty subjects were enrolled in this study. Alveolar hemorrhage was observed in 19 subjects (31.7%) with idiopathic interstitial pneumonia, acute respiratory distress syndrome, interstitial pneumonia with autoimmune features, drug-induced lung injury, eosinophilic pneumonia, adenocarcinoma, and systemic lupus erythematosus. The use of anticoagulants was a significant risk factor for alveolar hemorrhage (odds ratio 7.57, p = 0.049). Patients with alveolar hemorrhage required intubated mechanical ventilation more frequently (63.2% vs. 24.4%, p = 0.005) and had higher in-hospital mortality rates (26.3% vs. 4.9%, p = 0.028) than those without alveolar hemorrhage. Conclusions: Alveolar hemorrhage was observed in various etiologies. The use of anticoagulants was a significant risk factor for alveolar hemorrhage. Patients with alveolar hemorrhage showed more severe respiratory failure and had higher in-hospital mortality than those without alveolar hemorrhage.

Novel acute hypersensitivity pneumonitis model induced by airway mycosis and high dose lipopolysaccharide

Background Inhalation of fungal spores is a strong risk factor for severe asthma and experimentally leads to development of airway mycosis and asthma-like disease in mice. However, in addition to fungal spores, humans are simultaneously exposed to other inflammatory agents such as lipopolysaccharide (LPS), with uncertain relevance to disease expression. To determine how high dose inhalation of LPS influences the expression of allergic airway disease induced by the allergenic mold Aspergillus niger (A. niger). Methods C57BL/6J mice were intranasally challenged with the viable spores of A. niger with and without 1 μg of LPS over two weeks. Changes in airway hyperreactivity, airway and lung inflammatory cell recruitment, antigen-specific immunoglobulins, and histopathology were determined. Results In comparison to mice challenged only with A. niger, addition of LPS (1 μg) to A. niger abrogated airway hyperresponsiveness and strongly attenuated airway eosinophilia, PAS+ goblet cells and TH2 responses while enhancing TH1 and TH17 cell recruitment to lung. Addition of LPS resulted in more severe, diffuse lung inflammation with scattered, loosely-formed parenchymal granulomas, but failed to alter fungus-induced IgE and IgG antibodies. Conclusions In contrast to the strongly allergic lung phenotype induced by fungal spores alone, addition of a relatively high dose of LPS abrogates asthma-like features, replacing them with a phenotype more consistent with acute hypersensitivity pneumonitis (HP). These findings extend the already established link between airway mycosis and asthma to HP and describe a robust model for further dissecting the pathophysiology of HP.

Childhood Interstitial and Diffuse Lung Disease in an Immunocompetent Patient Without Exposure

Childhood interstitial and diffuse lung disease (chILD) is a heterogeneous group of rare and chronic respiratory disorders with an estimated prevalence of 1.5 cases per million children aged 0-18 years. Presented is the case of an immunocompetent young girl who presented with symptoms of recurrent cough and clubbing

Clinical Analysis of Transbronchial Cryobiopsy in Diagnosis of Diffuse Lung Disease

Background: Rapid advances in TBCB in recent years have allowed its gradual acceptance as a diagnostic method for DLD, and an alternative to surgical lung biopsy . However, the various guidelines have yet to provide clear recommendations for TBCB. This study investigated the diagnostic value of transbronchial cryobiopsy (TBCB) for identifying diffuse lung disease (DLD) .Methods: The clinical data was reviewed of 34 patients who showed initial signs of diffuse lung lesions, interstitial pneumonia, bronchial asthma, lung cancer/infection, or pulmonary alveolar proteinosis; and underwent TBCB from December 2018 to March 2021. The safety and effectiveness of TBCB in identifying the etiology of DLD was analyzed.Results: Clear pathomorphological diagnoses were obtained for 27 (79.4%) patients, based on clinical characteristics and pathology: pulmonary fibrosis, adenocarcinoma, alveolar proteinosis, extrinsic allergic alveolitis, tuberculous granulomatous inflammation, and interstitial pneumonia. Four (11.8%) patients required multi-disciplinary discussion for diagnostic confirmation (of diffuse lesions, interstitial pneumonia, and lung infection). The etiology of 3 cases remained unknown. The rate of DLD diagnosis via TBCB was 91.2% (31/34). Associated with the TBCB procedure, 9 (26.5%) patients developed pneumothorax (6 mild, 3 moderate), and 29 (85.3%) post-biopsy bleeding (all grade 1, requiring suction and compression, but no other intervention or surgery). The average hospitalization cost and length of stay were 7988 RMB (1233 USD) and 5.48 days, respectively.Conclusion: TBCB is safe, cost-effective, requires a short hospitalization, and the diagnostic confirmation rate for DLD is high.

Application of Multi-Slice Spiral CT in the Evaluation of Diffuse Lung Diseases

This article analyzes the manifestations, characteristics, and significance of multi-slice spiral CT for diffuse lung disease, and evaluates the diagnostic value of multi-slice CT multi-directional reconstruction for diffuse lung disease. After performing multi-slice spiral CT examination on the patient and collecting relevant data, the characteristic multi-slice CT imaging findings of diffuse lung disease were determined by statistical analysis. Diffuse lung disease is representative in multi-slice spiral CT image imaging manifestations of the disease include multiple disseminated small nodules, multiple voids, ground glass shadows, and lung consolidation. And analyze the correlation of image performance, and then use statistical methods to analyze and evaluate the value of multi-slice spiral CT characteristic images in the diagnosis of diffuse lung disease, and analyze the characteristics of these characteristic multi-slice CT image appearances. The use of high-resolution CT to screen the characteristic CT imaging findings of the same research object, and then to perform a statistical analysis of the diagnostic differences with multi-slice spiral CT, further confirmed the importance of multi-slice CT for diffuse lung disease Diagnostic value. Studies have shown that multi-slice CT imaging technology is of great significance in the evaluation of diffuse lung diseases.