J Korean Med Sci. 2022 Jun 06;37(22):e78. English.
Published online May 20, 2022.
© 2022 The Korean Academy of Medical Sciences.
Original Article

Impact of Mediastinal Lymphadenopathy on the Severity of COVID-19 Pneumonia: A Nationwide Multicenter Cohort Study

Jong Eun Lee,1 Won Gi Jeong,2 Bo Da Nam,3 Soon Ho Yoon,4 Yeon Joo Jeong,5 Yun-Hyeon Kim,1 Sung Jin Kim,6 and Jin Young Yoo6
    • 1Department of Radiology, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea.
    • 2Department of Radiology, Chonnam National University Medical School, Chonnam National University Hwasun Hospital, Hwasun, Korea.
    • 3Department of Radiology, Soonchunhyang University Seoul Hospital, Seoul, Korea.
    • 4Department of Radiology, Seoul National University Hospital, Seoul National College of Medicine, Seoul, Korea.
    • 5Department of Radiology and Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.
    • 6Department of Radiology, Chungbuk National University College of Medicine, Chungbuk National University Hospital, Cheongju, Korea.
Received August 05, 2021; Accepted January 06, 2022.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

We analyzed the differences between clinical characteristics and computed tomography (CT) findings in patients with coronavirus disease 2019 (COVID-19) to establish potential relationships with mediastinal lymphadenopathy and clinical outcomes.

Methods

We compared the clinical characteristics and CT findings of COVID-19 patients from a nationwide multicenter cohort who were grouped based on the presence or absence of mediastinal lymphadenopathy. Differences between clinical characteristics and CT findings in these groups were analyzed. Univariate and multivariate analyses were performed to determine the impact of mediastinal lymphadenopathy on clinical outcomes.

Results

Of the 344 patients included in this study, 53 (15.4%) presented with mediastinal lymphadenopathy. The rate of diffuse alveolar damage pattern pneumonia and the visual CT scores were significantly higher in patients with mediastinal lymphadenopathy than in those without (P < 0.05). A positive correlation between the number of enlarged mediastinal lymph nodes and visual CT scores was noted in patients with mediastinal lymphadenopathy (Spearman’s ρ = 0.334, P < 0.001). Multivariate analysis showed that mediastinal lymphadenopathy was independently associated with a higher risk of intensive care unit (ICU) admission (odds ratio, 95% confidence interval; 3.25, 1.06-9.95) but was not significantly associated with an increased risk of in-hospital death in patients with COVID-19.

Conclusion

COVID-19 patients with mediastinal lymphadenopathy had a larger extent of pneumonia than those without. Multivariate analysis adjusted for clinical characteristics and CT findings revealed that the presence of mediastinal lymphadenopathy was significantly associated with ICU admission.

Graphical Abstract

Keywords
Computed Tomography; COVID-19; Mediastinal Lymphadenopathy; Pneumonia; Intensive Care Unit

INTRODUCTION

Computed tomography (CT) plays a leading role in the identification and categorization of pneumonia in patients with coronavirus disease 2019 (COVID19). Typical and atypical CT features of COVID-19 pneumonia, including peripheral, bilateral, lower lobe, and posterior dominant distribution of ground-glass opacities (GGOs) with or without consolidations in lung regions, have been recently described.1, 2, 3, 4 Interlobular septal thickening, crazy-paving pattern, reversed halo sign, or other findings of organizing pneumonia have been reported depending on the time course of disease.4, 5 In addition to the quantitative extent of pneumonia, CT features, including consolidation, linear opacities, and crazy-paving pattern, have been reported as factors that reflect the severity of COVID-19 and may have a potential role in prognostication.6, 7

Among the CT features of COVID-19 pneumonia, mediastinal lymphadenopathy is rare and has a prevalence of 3-5% according to systematic meta-analyses.8, 9 However, in one study conducted in France, mediastinal lymphadenopathy was observed in 66% of COVID-19 patients admitted to the intensive care unit (ICU).10 Similarly, other studies have reported that mediastinal lymphadenopathy was significantly more frequent in critically ill patients and those who died during hospitalization.7, 11, 12 These studies suggest that there may be a potential link between the presence of mediastinal lymphadenopathy and COVID-19 severity; however, the association of mediastinal lymphadenopathy with disease severity and prognosis has not been clearly established.

This study aimed to determine whether the presence of mediastinal lymphadenopathy and specific clinical or CT characteristics are associated with COVID-19 disease severity and prognosis.

METHODS

Patients

The participants of this study included 522 patients enrolled in the Korean Imaging Cohort for COVID-19 (KICC-19), which was established by the Korean Society of Thoracic Radiology (KSTR) in July 202013 and 90 patients enrolled in two tertiary center cohorts (Chungbuk National University Hospital and Chonnam National University Hospital). From February 2020 to May 2020, 612 adult patients aged ≥ 18 years who were diagnosed with COVID-19 by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) using nasal and oropharyngeal swabs were enrolled. Other respiratory pathogens capable of causing similar symptoms were excluded by RT-PCR and sputum cultures. Of these patients (n = 612), 344 underwent chest CT within 10 days of COVID-19 diagnosis and were included in the analysis. Patients with other causes of mediastinal lymphadenopathy, such as active cancer, sarcoidosis, or heart failure, were excluded.

Clinical data collection and definitions of clinical outcomes

Demographics, clinical symptoms, comorbidities, initial laboratory findings, and clinical outcomes of the 344 patients were evaluated. Laboratory analyses included neutrophil, lymphocyte, and thrombocyte counts and measurements of serum C-reactive protein (CRP) and blood urea nitrogen (BUN) levels. Clinical outcomes included the requirement for supplemental oxygen, ICU admission, acute respiratory distress syndrome (ARDS), and in-hospital death. ARDS was diagnosed based on the Berlin 2012 ARDS diagnostic criteria.14 In-hospital death was defined as deaths resulting from clinically compatible illnesses in patients with COVID-19 during hospitalization.15

CT imaging protocol and reconstruction profiles

All CT examinations were performed using multi-detector CT scanners with > 16 channels. Scans were obtained from the base to apex of each lung. Intravenous contrast medium was injected in 15 patients (4%). Of the 344 scans, 188 (55%) and 144 (42%) were obtained using slice thicknesses of ≤ 1.5 mm and 1.5-3 mm, respectively; only 12 CT scans (3%) were performed using a slice thickness of 5 mm. After anonymization, all images were transferred to the Asan Image Metrics Clinical Trial Center, a cloud-based data storage platform for research supported by the KSTR and the Korean Society of Radiology. In this system, a dedicated web viewer was provided for CT image analysis.

CT image analysis

Two thoracic radiologists (J.E.L. and Y.J.Y. with 7 and 13 years of chest CT experience, respectively) reviewed the CT images by consensus. If consensus was not achieved, the senior reader’s interpretation was accepted. The radiologists were blinded to patient clinical outcomes. Only the initial CT scan was analyzed if a patient underwent multiple CT examinations within 10 days of COVID-19 diagnosis. The time between symptom onset and CT scan was recorded for each patient.

Mediastinal lymphadenopathy was defined as one or more enlarged lymph nodes with a short-axis diameter of > 10 mm. Calcified enlarged mediastinal lymph nodes or anthracotic pigmented lymph nodes resulting from prior inflammation were excluded. Anthracotic pigmented lymph nodes were defined as those with > 70 HU according to the region-of-interest–based measurement, which indicates histopathologically internal fibrotic micronodule formation.16 The numbers and distribution of enlarged mediastinal lymph nodes were assessed according to the lymph node map of the International Association for the Study of Lung Cancer.17 Representative CT images of a COVID-19 patient with and without mediastinal lymphadenopathy are shown in Figs. 1 and 2.

Fig. 1
Representative case of a coronavirus disease 2019 patient with mediastinal lymphadenopathy in a 71-year-old man. (A) Axial mediastinal-widow CT image shows an enlarged mediastinal lymph node in station 4R (white arrow). (B) Axial lung-window CT image obtained at the same level shows multifocal areas of ground-glass opacity with diffuse alveolar damage pattern in bilateral lungs.
CT = computed tomography.

Fig. 2
Representative case of a coronavirus disease 2019 patient without mediastinal lymphadenopathy in a 75-year-old woman. (A) Axial mediastinal-widow CT image shows a small lymph node measuring less than 1 cm in short axis diameter at station 4R (white arrow). (B) Axial lung-window CT image shows small areas of ground-glass opacity in bilateral lower lobes (white arrows).
CT = computed tomography.

CT findings of parenchymal abnormalities, including GGO, consolidation, reversed halo sign, reticulation, subpleural lines, crazy-paving patterns, traction bronchiectasis, and centrilobular nodules, were recorded. A reversed halo sign was defined as a focally rounded area of GGO surrounded by a complete or nearly complete ring of consolidation. A crazy-paving pattern was defined as a thickened interlobular septum and intralobular lines superimposed on a background of GGO.18 The presence of pleural effusion was also recorded. Distributions of parenchymal abnormalities in the axial (peripheral, peribronchovascular, and diffuse) and craniocaudal (upper to mid zone, lower zone, and random) planes were evaluated.

Bilateral involvement and diffuse alveolar damage (DAD) patterns were also recorded. A DAD pattern was defined as patchy or extensive air-space consolidation or GGO without zonal predominance. CT patterns of COVID-19 pneumonia were classified into typical, indeterminate, and atypical according to the Radiological Society of North America expert consensus document.4 The extent of each parenchymal lesion was assessed using a visual CT scoring system. Each lung lobe was visually scored from 0 to 5 as follows: 0, no involvement; 1, < 5%; 2, 5–24%; 3, 25–49%; 4, 50–74%; and 5, ≥ 75% involvement.19 Visual CT scores were the sum of the individual lobar scores and ranged from 0–25.

Statistical analysis

All statistical analyses were performed using SPSS software, version 25.0 (IBM, Armonk, NY, USA). The Pearson’s chi-square test for categorical variables and the independent t-test for continuous variables were used to determine the differences between clinical characteristics and CT findings in patients with and without mediastinal lymphadenopathy.

Inter-reader agreement for the presence or absence of mediastinal lymphadenopathy was calculated as κ of agreement. κ < 0.40 was interpreted as poor agreement, 0.41–0.60 as moderate, 0.61-0.80 as substantial, and 0.81–1 as almost perfect agreement according to Cohen’s kappa coefficient.20

To evaluate the correlation between the number of enlarged lymph nodes and the extent of pneumonia, Spearman’s correlation analysis was performed. Factors associated with ICU admission were identified by univariate and multivariate logistic regression analysis. Those associated with in-hospital death was identified by univariate and multivariate Cox proportional-hazard model. Differences were considered statistically significant at P < 0.05.

Ethics statement

This retrospective study was approved by the Institutional Review Board of our institutions (approval numbers CBNUH 2020-04-003 and CNUH-2020-123), and the requirement for informed consent was waived owing to the retrospective nature of the study.

RESULTS

Baseline characteristics of COVID-19 patients

The mean time between symptom onset and chest CT examination was 5.8 ± 4.6 days (range: 0-10). The baseline clinical characteristics of the 344 patients, all of whom underwent a chest CT scan, are presented in Table 1. A total of 127 (39.0%) patients had at least one comorbidity, such as hypertension, diabetes, cardiovascular disease, history of cancer, chronic obstructive pulmonary disease (COPD), chronic kidney disease, dyslipidemia, chronic liver disease, asthma, and dementia, and 275 (79.9%) patients had at least one COVID-19 symptom. Of the 344 patients included in this study, 82 (23.8%) required supplemental oxygen, 34 (9.9%) were admitted to the ICU, 16 (4.7%) developed ARDS, and 10 (2.9%) died during their hospital stay. The mean length of hospitalization was 27.99 ± 14.7 days.

Table 1
Baseline clinical characteristics of patients with COVID-19 at hospital admission (N = 344)

Clinical characteristics of patients with and without mediastinal lymphadenopathy

The clinical characteristics of the patients with and without mediastinal lymphadenopathy are summarized in Table 2. Of the 344 patients included in this study, 53 (15.4%) had mediastinal lymphadenopathy, with a higher mean age than patients without mediastinal lymphadenopathy. Having at least one comorbidity and COVID-19 symptoms were significantly more common in patients with mediastinal lymphadenopathy than in those without (P < 0.001, P < 0.001, and P = 0.004, respectively). The CRP level was significantly higher in patients with mediastinal lymphadenopathy than in those without (P < 0.001); however, no significant differences between the two groups were observed in terms of neutrophil, lymphocyte, and thrombocyte counts and BUN levels. The number of patients with mediastinal lymphadenopathy requiring oxygen supply, ICU admission, and ARDS were significantly higher than those without (P < 0.001).

Table 2
Clinical characteristic of patients with and without mediastinal lymphadenopathy

CT findings in patients with and without mediastinal lymphadenopathy

The number and distribution of enlarged mediastinal lymph nodes in patients with mediastinal lymphadenopathy are summarized in Fig. 3. The most common regions for mediastinal lymphadenopathy were stations 4R, 7, and 2R in this order. The degree of agreement in identifying the presence or absence of mediastinal lymphadenopathy between the two readers was almost perfect (κ = 0.890).

Fig. 3
The number and distribution of enlarged mediastinal lymph nodes in patients with coronavirus disease 2019. The most common regions for mediastinal lymphadenopathy were stations 4R, 7, and 2R in that order.

Visual CT scores were significantly higher in patients with mediastinal lymphadenopathy than in those without (P < 0.05) (Fig. 4). The number of enlarged mediastinal lymph nodes was positively correlated with visual CT scores (Spearman’s ρ = 0.334, P < 0.001) (Fig. 5A) and CRP level (ρ = 0.307, P = 0.025) (Fig. 5B).

Fig. 4
Mean visual CT score of coronavirus disease 2019 patients with or without mediastinal lymphadenopathy. The mean visual CT score was significantly higher in those with mediastinal lymphadenopathy than those without (P < 0.001).
CT = computed tomography.

Fig. 5
Correlation of the number of enlarged lymph nodes with visual CT scores and CRP level. (A) Scatter plot of the number of enlarged lymph nodes with visual CT scores and the CRP level. There was a positive correlation between the number of enlarged lymph nodes and the visual CT scores (Spearman’s ρ = 0.334, P < 0.001). (B) There was a positive correlation between the number of enlarged lymph nodes and the CRP levels (Spearman’s ρ = 0.307, P = 0.025).
CT = computed tomography, CRP = C-reactive protein.

The CT findings of COVID-19 pneumonia patients with and without mediastinal lymphadenopathy are summarized in Table 3. Of the 344 patients, 58 (16.8%) had normal chest CT findings. The rate of any parenchymal abnormalities detected on chest CT scan was significantly higher in patients with mediastinal lymphadenopathy than those without. Parenchymal abnormalities, including consolidation, crazy-paving pattern, reversed halo, reticulation, subpleural line, and traction bronchiectasis, and pleural effusion were more common in patients with than without mediastinal lymphadenopathy (Table 3). The frequencies of diffuse axial distribution and random craniocaudal distribution were higher in patients with mediastinal lymphadenopathy than in those without. Similarly, patterns of bilateral involvement and DAD pattern were significantly more common patients with mediastinal lymphadenopathy. The frequency of CT pattern was not significantly different between the two groups.

Table 3
CT findings of COVID-19 pneumonia in patients with and without mediastinal lymphadenopathy

Risk factors related to ICU admission of COVID-19 patients

Univariate and multivariate logistic regression analyses for risk factors related to ICU admission of patients with COVID-19 are summarized in Table 4. Univariate analysis revealed the following as significant factors related to ICU admission of patients with COVID-19 pneumonia: older age; male sex; hypertension, diabetes, and cardiovascular disease; higher neutrophil count; higher CRP level; presence of mediastinal lymphadenopathy; presence of DAD pattern pneumonia; and higher visual CT scores. Multivariate logistic regression analysis adjusted for clinical characteristics and CT findings revealed that male sex (odds ratio [OR], 3.76; 95% confidence interval (CI), 1.25–11.31), higher level of CRP (OR, 1.11; 95% CI, 1.03–1.21), presence of mediastinal lymphadenopathy (OR, 3.25; 95% CI, 1.06–9.95), and higher visual CT scores (OR, 1.25; 95% CI, 1.10–1.44) were independent significant factors related to ICU admission of COVID-19 patients.

Table 4
Odds ratiosa for ICU admission among COVID-19 patients

Risk factors related to in-hospital death of patients with COVID-19

Univariate and multivariate Cox proportional-hazards models for risk factors related to in-hospital death of patients with COVID-19 are summarized in Table 5. Univariate analysis revealed that older age, male sex, hypertension, diabetes, cardiovascular disease, and COPD, higher neutrophil count, higher CRP level, presence of DAD pattern pneumonia, and higher visual CT scores were significant factors related to in-hospital death of COVID-19 patients. Multivariate analysis adjusted for clinical characteristics and CT findings revealed that diabetes (hazard ratio [HR], 26.58; 95% CI, 3.08–229.58), COPD (HR, 32.00; 95% CI, 2.13–482.01), chronic kidney disease (HR, 27.08; 95% CI, 1.53–479.94), and higher level of CRP (HR, 1.19; 95% CI, 1.04–1.37) were independent significant factors related to in-hospital death of COVID-19 patients.

Table 5
Hazard ratiosa for in-hospital death among COVID-19 patients

DISCUSSION

This study evaluated the clinical implication and prognostic role of mediastinal lymphadenopathy in patients with COVID-19 pneumonia. Mediastinal lymphadenopathy was observed in 15.4% of the study cohort. Our results suggest that the frequency of any parenchymal abnormalities on chest CT scans and visual CT scores were significantly higher in patients with mediastinal lymphadenopathy than in those without. Among the patient with presence of pneumonia on chest CT scans, the rate of DAD pattern was significantly higher in patients with mediastinal lymphadenopathy than in those without. Adjusted multivariate logistic regression analysis showed male gender, higher level of CRP, higher visual CT score, and presence of mediastinal lymphadenopathy were independently associated with a higher risk of ICU admission in patients with COVID-19 pneumonia. Adjusted multivariate Cox proportional-hazards model showed diabetes, COPD, and higher level of CRP were independently associated with a higher risk of in-hospital death in our study.

Parenchymal abnormalities, including consolidation, crazy-paving patterns, reversed halo sign, reticulation, subpleural line, traction bronchiectasis, and pleural effusion, were more frequently observed in patients with mediastinal lymphadenopathy. We found that all patients with mediastinal lymphadenopathy had at least one parenchymal abnormality. These parenchymal abnormalities indicate disease progression and severity in patients with COVID-19 as reported by previous studies.7, 21 Moreover, the visual CT score, which reflects the overall burden of parenchymal abnormalities in our study, was significantly higher in patients with mediastinal lymphadenopathy than those without. This quantitative burden of pneumonia has been previously demonstrated as a significant predictive factor for adverse outcomes, such as ICU admission, mechanical ventilation, vasopressor therapy, or death, of COVID-19 pneumonia patients.22 Additionally, the presence of mediastinal lymphadenopathy and the more extensive parenchymal involvement of pneumonia have been more commonly observed in COVID-19 pneumonia than other types of viral pneumonia,23 indicating that COVID-19 pneumonia induces a stronger immune response than other viral pneumonias. Furthermore, we found that not only the visual CT score but also the CRP level was significantly higher in patients with mediastinal lymphadenopathy than in those without, and that the number of enlarged lymph nodes was significantly correlated with both visual CT scores and CRP level. Therefore, the presence of mediastinal LAP may reflect active inflammation and host immune response of the lung in patients with COVID-19 and may have a significant association with severe COVID-19 pneumonia.

We found that DAD pattern, as well as bilateral and diffuse involvement, of COVID-19 pneumonia was more frequently observed in patients with mediastinal lymphadenopathy than in those without. DAD is a histologic hallmark of ARDS in patients with COVID-19.24 Jeong et al.25 identified extensive parenchymal abnormalities and DAD patterns of COVID-19 pneumonia as independent factors associated with clinical severity and poor clinical outcome, regardless of clinical risk factors. Jin et al.26 found that the DAD pattern of COVID-19 pneumonia was significantly correlated with adverse outcomes, including ICU admission, use of mechanical ventilation, or death, as well as pulmonary residual sequelae. The higher frequency of DAD pattern pneumonia we noted in patients with mediastinal lymphadenopathy may be associated with worse clinical outcomes in these patients.

In our study, mediastinal lymphadenopathy was significantly associated with ICU admission in patients with COVID-19 but not with in-hospital deaths. These findings are inconsistent with a previous study on the relationship between mediastinal lymphadenopathy and 30-day mortality in patients with COVID-19.12 The mortality rate reported in this previous study was 8.4%, whereas that in our study was 2.9%. Moreover, in the previous study, the mean age of the patients was 56.9 years, and the rate of comorbidity was 53.5%. In our study, the mean age was 54.1 years, and the comorbidity rate was 37.2%. Differences in the prevalence rates of COVID-19 may have influenced the distribution of hospitalized patients, which may have resulted in differences in comorbidity and in-hospital death rates between these two studies.

Our study showed associations between the risk of poor clinical outcomes, such as ICU admission and in-hospital death, and clinical characteristics. Among the clinical characteristics, we found that male sex and higher level of CRP were significantly associated with increased risk of ICU admission and that older age, diabetes, COPD, chronic kidney disease, and higher CRP level were significantly associated with increased risk of in-hospital death in patients with COVID-19. According to data adopted by the Centers for Disease Control and Prevention, older age, diabetes, COPD, and chronic kidney disease are risk factors for severe COVID-19.27 In a previous study analyzing the risk factors for poor clinical outcome of COVID-19 patients in Korea, older age, male sex, and higher number of comorbidities (including diabetes, COPD, and chronic kidney disease) were similarly identified as risk factors associated with in-hospital death and severe cases requiring oxygen therapy.28 Elevated CRP level, indicative of an inflammatory condition, was also reported as a risk factor for severe disease course and in-hospital death in patients with COVID-19.29, 30 These findings are consistent with our results.

This study had some limitations that warrant consideration. First, there may have been a selection bias owing to the retrospective study design and the inclusion of COVID-19 patients who underwent chest CT. Second, the timing between symptom onset and CT scan varied, which may have affected CT results. However, to address this limitation, we included patients who underwent chest CT within 10 days of RT-PCR-based diagnosis. Third, as most CT images were non-enhanced CT, there was a limitation in the evaluation of lymph nodes; therefore, evaluation of hilar lymph node was not performed. Fourth, serial CT scans over time were not evaluated in our study; thus, it was difficult to evaluate the association between long-term prognosis and the presence of mediastinal lymphadenopathy. Further studies that include long-term follow-up CT scans are required.

In conclusion, COVID-19 patients with mediastinal lymphadenopathy had a larger extent of pneumonia than those without. Multivariate analysis adjusted for clinical characteristics and CT findings revealed that the presence of mediastinal lymphadenopathy was independently associated with ICU admission. Thus, mediastinal lymphadenopathy should not be overlooked and may be considered as reflective of COVID-19 pneumonia severity.

Notes

Disclosure:The authors have no potential conflicts of interest to disclose.

Author Contributions:

  • Conceptualization: Lee JE, Yoo JY, Yoon SH.

  • Data curation: Lee JE, Yoo JY, Jeong WG, Nam BD.

  • Formal analysis: Lee JE, Yoo JY.

  • Investigation: Lee JE, Yoo JY.

  • Methodology: Lee JE, Yoo JY.

  • Software: Yoon SH, Yoo JY, Nam BD.

  • Validation: Yoo JY.

  • Visualization: Lee JE, Yoo JY, Yoon SH.

  • Writing - original draft: Lee JE, Yoo JY.

  • Writing - review & editing: Yoon SH, Jeong YJ, Kim YH, Kim SJ.

References

    1. Ye Z, Zhang Y, Wang Y, Huang Z, Song B. Chest CT manifestations of new coronavirus disease 2019 (COVID-19): a pictorial review. Eur Radiol 2020;30(8):4381–4389.
    1. Pan F, Ye T, Sun P, Gui S, Liang B, Li L, et al. Time course of lung changes at chest CT during recovery from 2019 coronavirus disease 2019 (COVID-19). Radiology 2020;295(3):715–721.
    1. Wei J, Xu H, Xiong J, Shen Q, Fan B, Ye C, et al. 2019 novel coronavirus (COVID-19) pneumonia: serial computed tomography findings. Korean J Radiol 2020;21(4):501–504.
    1. Simpson S, Kay FU, Abbara S, Bhalla S, Chung JH, Chung M, et al. Radiological Society of North America expert consensus document on reporting chest CT findings related to COVID-19: endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA. Radiol Cardiothorac Imaging 2020;2(2):e200152
    1. Kwee TC, Kwee RM. Chest CT in COVID-19: what the radiologist needs to know. Radiographics 2020;40(7):1848–1865.
    1. Li Y, Yang Z, Ai T, Wu S, Xia L. Association of “initial CT” findings with mortality in older patients with coronavirus disease 2019 (COVID-19). Eur Radiol 2020;30(11):6186–6193.
    1. Li K, Wu J, Wu F, Guo D, Chen L, Fang Z, et al. The clinical and chest CT features associated with severe and critical COVID-19 pneumonia. Invest Radiol 2020;55(6):327–331.
    1. Bao C, Liu X, Zhang H, Li Y, Liu J. Coronavirus disease 2019 (COVID-19) CT findings: a systematic review and meta-analysis. J Am Coll Radiol 2020;17(6):701–709.
    1. Zhu J, Zhong Z, Li H, Ji P, Pang J, Li B, et al. CT imaging features of 4121 patients with COVID-19: A meta-analysis. J Med Virol 2020;92(7):891–902.
    1. Valette X, du Cheyron D, Goursaud S. Mediastinal lymphadenopathy in patients with severe COVID-19. Lancet Infect Dis 2020;20(11):1230.
    1. Sardanelli F, Cozzi A, Monfardini L, Bnà C, Foà RA, Spinazzola A, et al. Association of mediastinal lymphadenopathy with COVID-19 prognosis. Lancet Infect Dis 2020;20(11):1230–1231.
    1. Satici C, Cengel F, Gurkan O, Demirkol MA, Altunok ES, Esatoglu SN. Mediastinal lymphadenopathy may predict 30-day mortality in patients with COVID-19. Clin Imaging 2021;75:119–124.
    1. Yoon SH, Ham SY, Nam BD, Chae KJ, Lee D, Yoo JY, et al. Establishment of a nationwide Korean imaging cohort of coronavirus disease 2019. J Korean Med Sci 2020;35(46):e413
    1. Ranieri VM, Rubenfeld GD, Thompson BT, Ferguson ND, Caldwell E, Fan E, et al. Acute respiratory distress syndrome: the Berlin Definition. JAMA 2012;307(23):2526–2533.
    1. World Health Organization. Medical certification, ICD mortality coding, and reporting mortality associated with COVID-19: technical note, 7 June 2020. [Updated 2020]. [Accessed April 15, 2017].
    1. Shim SS, Lee KS, Kim BT, Chung MJ, Lee EJ, Han J, et al. Non-small cell lung cancer: prospective comparison of integrated FDG PET/CT and CT alone for preoperative staging. Radiology 2005;236(3):1011–1019.
    1. Rusch VW, Asamura H, Watanabe H, Giroux DJ, Rami-Porta R, Goldstraw P, et al. The IASLC lung cancer staging project: a proposal for a new international lymph node map in the forthcoming seventh edition of the TNM classification for lung cancer. J Thorac Oncol 2009;4(5):568, 77.
    1. Hansell DM, Bankier AA, MacMahon H, McLoud TC, Müller NL, Remy J. Fleischner Society: glossary of terms for thoracic imaging. Radiology 2008;246(3):697–722.
    1. Francone M, Iafrate F, Masci GM, Coco S, Cilia F, Manganaro L, et al. Chest CT score in COVID-19 patients: correlation with disease severity and short-term prognosis. Eur Radiol 2020;30(12):6808–6817.
    1. Kundel HL, Polansky M. Measurement of observer agreement. Radiology 2003;228(2):303–308.
    1. Chon Y, Kim JY, Suh YJ, Lee JY, Park JS, Moon SM, et al. Adverse initial CT findings associated with poor prognosis of coronavirus disease. J Korean Med Sci 2020;35(34):e316
    1. Grodecki K, Lin A, Cadet S, McElhinney PA, Razipour A, Chan C, et al. Quantitative burden of COVID-19 pneumonia on chest CT predicts adverse outcomes: a post-hoc analysis of a prospective international registry. Radiol Cardiothorac Imaging 2020;2(5):e200389
    1. Li X, Fang X, Bian Y, Lu J. Comparison of chest CT findings between COVID-19 pneumonia and other types of viral pneumonia: a two-center retrospective study. Eur Radiol 2020;30(10):5470–5478.
    1. Li Y, Wu J, Wang S, Li X, Zhou J, Huang B, et al. Progression to fibrosing diffuse alveolar damage in a series of 30 minimally invasive autopsies with COVID-19 pneumonia in Wuhan, China. Histopathology 2021;78(4):542–555.
    1. Jeong YJ, Nam BD, Yoo JY, Kim KI, Kang H, Hwang JH, et al. Prognostic implications of CT feature analysis in patients with COVID-19: a nationwide cohort study. J Korean Med Sci 2021;36(8):e51
    1. Jin C, Tian C, Wang Y, Wu CC, Zhao H, Liang T, et al. A pattern categorization of CT findings to predict outcome of COVID-19 pneumonia. Front Public Health 2020;8:567672
    1. Gandhi RT, Lynch JB, Del Rio C. Mild or moderate Covid-19. N Engl J Med 2020;383(18):1757–1766.
    1. Jang SY, Seon JY, Eun BL, Koh SB, Yoo JH, Lee WY, et al. Risk factors of outcomes of COVID-19 patients in Korea: focus on early symptoms. J Korean Med Sci 2021;36(18):e132
    1. Lee JY, Kim HA, Huh K, Hyun M, Rhee JY, Jang S, et al. Risk factors for mortality and respiratory support in elderly patients hospitalized with COVID-19 in Korea. J Korean Med Sci 2020;35(23):e223
    1. Suh HJ, Lee E, Park SW. Clinical characteristics of COVID-19: risk factors for early oxygen requirement after hospitalization. J Korean Med Sci 2021;36(19):e139

Metrics
Share
Figures

1 / 5

Tables

1 / 5

PERMALINK