Chronic Obstructive Pulmonary Disease (COPD) is a complex heterogeneous condition with various clinical and pathologic features. In recent years, technical advances in quantitative CT imaging have generated considerable interest because they can provide a more precise and objective assessment of COPD. Emphysema and small-airway disease, the two major components of COPD, and other comorbidities, including pulmonary vessel alterations, atherosclerosis, cachexia, and osteoporosis, can all be assessed by means of quantitative imaging parameters. Increasing numbers of studies provide promising reports indicating that such parameters are associated with clinical measures of disease severity, respiratory symptoms, COPD exacerbations, and mortality. Despite such optimistic results, there are still many obstacles to using this quantitative technology in everyday practice to manage COPD patients. In this article, we review the current technical status of quantitative CT assessment, emphasizing its clinical implications and limitations. We also discuss present challenges and the potential future role of quantitative CT imaging in assessing COPD.

Background: The Korean Society of Thoracic Radiology (KSTR) recently constructed a nation-wide coronavirus disease 2019 (COVID-19) database and imaging repository, referred to the Korean imaging cohort of COVID-19 (KICC-19) based on the collaborative efforts of its members. The purpose of this study was to provide a summary of the clinico-epidemiological data and imaging data of the KICC-19. Methods: The KSTR members at 17 COVID-19 referral centers retrospectively collected imaging data and clinical information of consecutive patients with reverse transcription polymerase chain reaction-proven COVID-19 in respiratory specimens from February 2020 through May 2020 who underwent diagnostic chest computed tomography (CT) or radiograph in each participating hospital. Results: The cohort consisted of 239 men and 283 women (mean age, 52.3 years; age range, 11–97 years). Of the 522 subjects, 201 (38.5%) had an underlying disease. The most common symptoms were fever (n = 292) and cough (n = 245). The 151 patients (28.9%) had lymphocytopenia, 86 had (16.5%) thrombocytopenia, and 227 patients (43.5%) had an elevated CRP at admission. The 121 (23.4%) needed nasal oxygen therapy or mechanical ventilation (n = 38; 7.3%), and 49 patients (9.4%) were admitted to an intensive care unit.Although most patients had cured, 21 patients (4.0%) died. The 465 (89.1%) subjects underwent a low to standard-dose chest CT scan at least once during hospitalization, resulting in a total of 658 CT scans. The 497 subjects (95.2%) underwent chest radiography at least once during hospitalization, which resulted in a total of 1,475 chest radiographs. Conclusion The KICC-19 was successfully established and comprised of 658 CT scans and 1,475 chest radiographs of 522 hospitalized Korean COVID-19 patients. The KICC-19 will provide a more comprehensive understanding of the clinical, epidemiological, and radiologic characteristics of patients with COVID-19.