Long-Term Follow-Up Study of COVID-19: Evaluation on Thin-Slice CT.

Purpose: To retrospectively analyse the CT imaging during the long-term follow-up of COVID-19 patients after discharge. Patients and Methods: A total of 122 patients entered the study group. All patients underwent CT examinations. The CT images, which included distribution and imaging signs, were evaluated by two chest radiologists. Laboratory examinations included routine blood work, biochemical testing, and SARS-CoV-2 antibody screening. Statistical methods include chi-square, Fisher's exact test, one-way analysis of variance, rank sum test and logistic regression by SPSS 17.0. Results: There were 22 (18.0%) patients in the mild group, 74 (60.7%) patients in the moderate group, and 26 (21.3%) patients in the severe-critical group. The median follow-up interval was 405 days (378.0 days, 462.8 days). Only monocytes, prothrombin activity, and γ-glutamyltransferase showed significant differences among the three groups. We found that the more severe the patient's condition, the more SARS-CoV-2 IgG antibodies existed. Only 11 patients (11.0%) showed residual lesions on CT. The CT manifestations included irregular linear opacities in nine cases (9.0%), reticular patterns in six cases (6.0%), and GGOs in five cases (5.0%). Conclusion: The proportion of residual lesions on CT in COVID-19 patients was significantly reduced after long-term follow-up. The patients' age and disease conditions were positively correlated with residual lesions.

Long-Term Follow-Up Study of COVID-19: Evaluation on Thin-Slice CT

Purpose To retrospectively analyse the CT imaging during the long-term follow-up of COVID-19 patients after discharge. Patients and Methods A total of 122 patients entered the study group. All patients underwent CT examinations. The CT images, which included distribution and imaging signs, were evaluated by two chest radiologists. Laboratory examinations included routine blood work, biochemical testing, and SARS-CoV-2 antibody screening. Statistical methods include chi-square, Fisher’s exact test, one-way analysis of variance, rank sum test and logistic regression by SPSS 17.0. Results There were 22 (18.0%) patients in the mild group, 74 (60.7%) patients in the moderate group, and 26 (21.3%) patients in the severe–critical group. The median follow-up interval was 405 days (378.0 days, 462.8 days). Only monocytes, prothrombin activity, and γ-glutamyltransferase showed significant differences among the three groups. We found that the more severe the patient’s condition, the more SARS-CoV-2 IgG antibodies existed. Only 11 patients (11.0%) showed residual lesions on CT. The CT manifestations included irregular linear opacities in nine cases (9.0%), reticular patterns in six cases (6.0%), and GGOs in five cases (5.0%). Conclusion The proportion of residual lesions on CT in COVID-19 patients was significantly reduced after long-term follow-up. The patients’ age and disease conditions were positively correlated with residual lesions.

CT appearances, patterns of progression, and follow-up of COVID-19: evaluation on thin-section CT.

BACKGROUND: To retrospectively analyze CT appearances and progression pattern of COVID-19 during hospitalization, and analyze imaging findings of follow-up on thin-section CT. METHODS: CT findings of 69 patients with COVID-19 were evaluated on initial CT, peak CT, and pre-discharge CT. CT pattern were divided into four types on CT progression. Lesion percentage of pulmonary lobe (lobe score) was graded. Correlation analysis was made between scores and intervals. 53 patients were followed up by CT. RESULTS: Among 69 patients, 33.3% exhibited improvement pattern, 65.2% peak pattern, 1.5% deterioration pattern, and 0% fluctuation pattern. The lobe scores were positively correlated with most of intervals. It was more common to observe consolidation, pleural thickening and pleural effusion on the peak CT, and irregular line and reticulation on pre-discharge CT. The peak-initial interval were shortened when the initial CT with consolidation and pleural thickening. The intervals were extended when the irregular lines appeared on peak CT and reticulation on pre-discharge CT. Among 53 follow-up patients, 37.7% showed normal chest CT, and 62.3% showed viral pneumonia remained that mainly included GGO (100.0%) and irregular lines (33.3%). CONCLUSIONS: COVID-19 displayed different appearances on CT as progressing. The peak pattern was the most common progression pattern. The CT appearances showed closely related to the intervals. The COVID-19 pneumonia can be remained or completely absorbed on CT with follow-up.

High prevalence of occult thrombosis in cases of mild/moderate COVID-19.

BACKGROUND AND PURPOSE: An increasing number of reports have observed thrombosis in severe cases of COVID-19. The aim of this study was to evaluate the incidence of thromboembolism in mild/moderate cases of COVID-19. All of the patients had normal coagulation tests and none had any overt thrombotic complications. Our findings indicate that it is important to screen the thrombotic status of cases with mild/moderate COVID-19. METHODS: Between 11 June and 8 July 2020, 23 patients with mild/moderate COVID-19 pneumonia consented to having computed tomography pulmonary angiography (CPTA) and computed tomography venography (CTV) scans of the lungs and extremity veins. Doppler ultrasound (DUS) was also performed in all patients for screening. The incidence, clinical manifestations, laboratory examinations, imaging features, and prognosis, of patients with venous thromboembolism (VTE) were analyzed and compared with those of patients with COVID-19 pneumonia without VTE. RESULTS: Nineteen patients (82.6%) had VTE, mainly distal limb thrombosis. Only one of the VTE patients was positive when screened by DUS; the other VTE patients were negative by DUS. All of the mild/moderate patients with VTE were screened by CTPA + CTV. Blood tests for inflammatory, coagulation, and biochemical, parameters were all within the normal range, except for WBC and LDH. CONCLUSIONS: When using CTV screening for DVT, we found that the incidence of thrombosis in patients with mild/moderate COVID-19 markedly increased to 82.6% (19/23). Screening for thrombosis is therefore important in patients with COVID-19. CTV is more sensitive than DUS for the detection of thrombosis. More research is now needed to evaluate the significance of thrombosis in COVID-19 pneumonia.

Chest CT Evaluation of 11 Persistent Asymptomatic Patients with SARS-CoV-2 Infection.

In total, 11 asymptomatic carriers who underwent nasal or oropharyngeal swab tests for SARS-CoV-2 after being in close contact with patients who developed symptomatic 2019 coronavirus disease (COVID-19) were enrolled in this study. The chest multidetector computed tomography (CT) images of the enrolled patients were qualitatively and quantitatively analyzed. The findings of the first chest CT were normal in 3 (27.3%) patients, 2 of whom were aged below 15 years. The lesions of 2 (18.2%) patients involved 1 lobe with unifocal presence. Subpleural lesions were observed in 7 (63.6%) patients. Ground glass opacity (GGO) was the most common sign observed in 7 (63.6%) patients. Crazy-paving pattern and consolidation were detected in 2 (18.2%) and 4 (36.4%) patients, respectively. Based on deep learning and quantitative analysis, the mean volume of intrapulmonary lesions in the first CT image was 85.73 ± 84.46 cm3. In patients with positive findings on CT images, the average interval between positive real-time reverse transcriptase polymerase chain reaction assay and peak volume on CT images was 5.1 ± 3.1 days. In conclusion, typical CT findings can be detected in over 70% of asymptomatic SARS-CoV-2 carriers. The initial presentation is typically GGO along the subpleural regions and bronchi, which absorbs in approximately 5 days.

Value of CT findings in predicting transformation of clinical types of COVID-19

Objective: To investigate the value of CT findings in predicting thetransformation of clinical types of COVID-19. Methods: From January 24 to February 6, 2020, the clinical and chest CT data of patients with common COVID-19 were analyzed retrospectively. A total of 64 patients were enrolled, including 32 males and 32 females, aged 18-76 (45±15) years. Based on the fact whether patients’ conditions had deteriorated into severe type, all the cases were divided into common type group (51 cases) and deteriorated type group (13 cases). Differences of CT findings in the two groups of patients were analyzed, and visual semi-quantitative scores were introduced to evaluate the pneumonia. Results: Compared with the common type group, the deteriorated type group was more likely to involve the left upper lobe, the right middle lobe and the lung far away from the pleura. The differences between the two groups were statistically significant (χ²= 5.897, P=0.027;χ²=8.549, P=0.005;χ²=10.169,P=0.002). The median of the involved lobes were 2 (1,5) in the common type group and 5 (4,5) in the deteriorated type group. The difference between the two groups was statistically significant (Z =-3.303, P=0.001). Taking the involved lobes (n=4) as the threshold, the sensitivity and specificity of the diagnosis of the common type to the deteriorated type patients were the highest, 76.9% and 74.5% respectively, and the area under the ROC curve was 0.787. Pneumonia score of the deteriorated group was 10 (4,16), higher than that of the common group [4 (1,13)], and the difference was statistically significant (Z=-4.040, P<0.001). Pneumonia score 8 as the threshold, the sensitivity and specificity of the general severe group were the highest, 69.2% and 86.3% respectively, and the area under ROC curve was 0.863. Conclusions: CT imaging has a profound value in the early prediction of deterioration in clinical type of COVID-19. It can help evaluate the severity of pneumonia in early stage. Range of lesions might be an important indicator for prognosis of common type COVID-19.

CT findings of COVID-19 in follow-up: comparison between progression and recovery

PURPOSE: We aimed to retrospectively analyze the imaging changes detected in the follow-up of coronavirus disease 2019 (COVID-19) patients on thin-section computed tomography (CT). METHODS: We included 54 patients diagnosed with COVID-19. The mean interval between the initial and follow-up CT scans was 7.82±3.74 days. Patients were divided into progression and recovery groups according to their outcomes. We evaluated CT images in terms of distribution of lesions and imaging manifestations. The manifestations included ground-glass opacity (GGO), crazy-paving pattern, consolidation, irregular line, and air bronchogram sign. RESULTS: COVID-19 lesions showed mainly subpleural distribution, which was accompanied by bronchovascular bundle distribution in nearly 30% of the patients. The lower lobes of both lungs were the most commonly involved. In the follow-up, the progression group showed more involvement of the upper lobe of the left lung than the recovery group. GGO was the most common sign. As the disease progressed, round GGO decreased and patchy GGO increased. On follow-up CT, consolidation increased in the progression group while decreasing in the recovery group. Air bronchogram sign was more commonly observed at the initial examination (90.9%) than at follow-up (30%) in the recovery group, but there was no significant change in the progression group. Pleural effusion and lymphadenopathy were absent in the initial examination, but pleural effusion was observed in three cases after follow-up. CONCLUSION: As COVID-19 progressed, round GGOs tended to evolve into patchy GGOs, consolidation increased, and pleural effusion could be occasionally observed. As COVID-19 resolved, the crazy-paving pattern and air bronchogram significantly decreased.