Follow-Up CT Results of COVID-19 Patients with Initial Negative Chest CT.

PURPOSE: To determine whether new pulmonary lesions will develop in COVID-19 patients with negative initial chest CT findings and to investigate their CT features and outcome during treatment. PATIENTS AND METHODS: Data were collected retrospectively from 29 patients who had tested positive for COVID-19 by reverse-transcription polymerase chain reaction testing but negative by initial chest CT from January 22 to February 17, 2020. Clinical manifestations, laboratory indicators, and follow-up CT data were evaluated. RESULTS: Among 317 confirmed COVID-19 patients, 29 (9.1%) (mean ± SD, 38.5 ± 20.5 years; 12 women) with negative initial chest CT findings were evaluated. New pulmonary lesions developed in 10 (34.5%) patients on follow-up CT. Mean time from onset of new lesions to initial CT was 5.8 ± 3.0 days (range: 2-12 days). New lesions (mean involved lobes and segments: 2.5 ± 1.6 [range: 1-5] and 4.5 ± 4.5 [range: 1-13]) were mainly spherical/patchy ground-glass opacities frequently located in the left lower lobe (9, 90.0%). Among the 10 patients, lesions in 6 (60.0%) indicated progression after occurrence, and those in 10 (100.0%) indicated significant absorption on latest CT. When new lesions developed, 6 (60.0%) patients developed new symptoms or had aggravated symptoms and 3 (30.0%) had decreased lymphocyte count. Patients with worsening symptoms had higher involvement of lung segments (mean: 6.5 ± 5.0, range: 1-13) than asymptomatic patients (mean: 1.5 ± 0.6, range: 1-2) (P = 0.057). CONCLUSION: In COVID-19 patients with negative initial chest CT findings, new pulmonary lesions may develop during treatment. Repeat CT is necessary for monitoring the disease, especially when patients have worsening symptoms or laboratory indicators.

Completed absorption of coronavirus disease 2019 (COVID-19) pneumonia lesions: a preliminary study.

Background: Complete absorption of coronavirus disease 2019 (COVID-19) pneumonia in a short term was not detailedly reported. We aimed to investigate the clinical and imaging characteristics of COVID-19 patients with complete absorption of pulmonary lesions. Methods: Retrospectively collected the clinical and chest CT data of 224 patients with COVID-19 in one regional medical center. Currently, pulmonary lesions in 37 patients were completely absorbed. The clinical manifestations, laboratory examinations, and CT findings of lesions for these patients were summarized. Results: Among the 37 patients (age, 39.0 ± 12.4 [14-63] years, 20 males), disease in 36 (97.3%) was mild and in 1 (2.7%) was from severe to mild. The most common symptoms were cough (24/37, 64.9%) and fever (23/37, 62.2%). Their laboratory indicators at admission were usually normal, while the white blood cell and neutrophil count significantly increased at discharge (p = 0.004, p = 0.006). On initial CT images, all patients had various pulmonary lesions (mean involved lobes: 2.8 ± 1.5, range: 1-5; mean involved segments: 6.6 ± 4.3, range: 1-16), which mainly manifested as multiple patchy and or spherical ground glass opacities (GGOs) (30/37, 81.1%) with fibrous strips (19/30, 63.3%) or consolidation (11/30, 36.7%). After treatment, lesions in most (33/37, 89.2%) patients were continuously absorbed. At discharge, previous lesions were mostly absorbed in 11 patients (11/37, 29.7%), the main residues were GGOs (24/37, 64.9%), followed by fibrous strips (13/37, 35.1%). On the latest CT, all the pulmonary lesions were completely absorbed, the duration of lesions was 31.6 ± 11.4 days (range: 5-50 days). Conclusion: The pulmonary lesions in some mild COVID-19 patients (generally with normal laboratory indicators at admission, GGOs as the main manifestation on initial CT, and representation of continuous absorption after treatment) could be completely absorbed with a mean duration of 31.6 days.

CT features and outcomes of newly developed pulmonary lesions in patients with Coronavirus Disease 2019 (COVID-19).

Background: In patients with coronavirus disease 2019 (COVID-19) pneumonia, whether new pulmonary lesions will continue to develop after treatment was unknown. This study aimed to determine whether new pulmonary lesions will develop after treatment in patients with COVID-19 pneumonia, and investigate their CT features and outcomes. Methods: This retrospective study included 56 consecutive patients with confirmed COVID-19 pneumonia from January 20 to March 5, 2020. Their initial and follow-up CT images and clinical data were reviewed. The CT manifestations of primary and newly developed pulmonary lesions and their changes after treatment were mainly evaluated. Results: Among the 56 patients (mean age: 48±15 years, 35 men) with COVID-19 pneumonia, 42 (75.0%) patients developed new pulmonary lesions during treatment. All new lesions developed before the nucleic acid test turned negative. Patients with new lesions were more likely to have lymphopenia (P=0.041) or increased C-reactive protein (CRP) levels (P<0.001) than those without new lesions. Of the 42 patients, 30 (71.4%) patients developed new lesions once, and 12 (28.6%) twice or thrice, which usually appeared when primary lesions were progressing (37, 88.1%) and 1-15 days after treatment. The newly developed lesions were usually multiple (38, 90.5%), distributed in the previously involved (39, 92.9%) or uninvolved (27, 64.3%) lobes, and manifested as ground-glass opacities (GGOs) with consolidation (23, 54.8%) or pure GGOs (19, 45.2%). After their occurrence, the new lesions in most patients (32, 76.2%) showed direct absorption, whereas those in some patients (10, 23.8%) progressed before absorption. Conclusion: During treatment, most patients with COVID-19 pneumonia will develop new pulmonary lesions, which usually manifest as multiple GGOs distributed around the primary lesions or in previously uninvolved lobes, and are subsequently absorbed directly.