Background
Since the COVID-19 outbreak in December 2019, the number of confirmed cases has been rapidly increasing. So far (March 15, 2020), COVID-19, has spread to 146 countries and territories across six continents, infecting more than 164,000 and killing more than 6,400 people. Currently, COVID-19 is considered one of the worst epidemics in human history.
The COVID-19 is a lineage B betacoronavirus. According to the internationally published virus classification, there are nine types of this betacoronavirus [
1], among which mouse hepatitis virus, rousettus bat coronavirus HKU9, and severe acute respiratory syndrome (SARS) are the most widely known. On February 11, 2020, the International Committee on Taxonomy of Viruses named COVID-19 as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [
2]. Although treatment for.
SARS-CoV-2 is still not available, researchers are currently working on creating vaccines and investigating clinical features of the infected population.
Recently, Wang et al examined the CT images of asymptomatic infected patients with COVID-19 and found that chest CT scans have an essential role in the screening of the population suspected of having infection [
3]. Besides, a previous report suggested that CT imaging may be very useful in the diagnosis of COVID-19 in patients with negative NAT [
4]. In the present study, we analyzed clinical data and CT images of 43 COVID-19. These data could contribute to timely and accurate identification of the clinical features, laboratory test results , and CT imaging findings of COVID-19, thereby resulting in early diagnosis, quarantine, and treatment.
Results
There were 43 patients in this group, including 20 males (46.5%) and 23 females (53.5%). Predominantly, these were middle-aged and elderly patients, with a mean age of 52.4±14.8 years (range, 19-78 years). Patient characteristics are showed in Table
1.
Table 1
Patient characteristics
Patient demographics |
Median age, years (range) | 52.4 ± 14.8 (19–78) |
Men | 20(46.5%) |
Women | 23(53.5%) |
Exposure history |
Exposure to epidemic area | 36(83.7%) |
Unknown exposure | 7(16.3%) |
Signs and symptoms |
Fever | 41(95.3%) |
Chest distress | 2(4.7%) |
Cough | 23(53.5%) |
Weak | 10(23.3%) |
Headache | 2(4.7%) |
Sore muscle | 8(18.6%) |
Gastrointestinal discomfort | 8(18.6%) |
Expectoration | 6(14.0%) |
Sore throat | 6(14.0%) |
Pharyngeal congestion | 4(9.3%) |
Dizziness | 3(7.0%) |
Chills | 8(18.6%) |
A baseline chest CT scan was abnormal in 34 patients (Table
2); 23 (67.6%) showed lesions involving both lungs, and 24 (70.6%) reported bilateral multifocal lesions, with the predominant lower lobe. In addition, there were 29 patients (85.3%) with GGO and vascular thickening in the lesion, 16 (47.1%) with air bronchogram sign, 29 (85.3%) with interlobular septal thickening, 22 (65.2%) with “feather signs”, 18 (52.9%) with “dandelion sign” and 21 (61.8%) with pulmonary fibrous tissue proliferation. The partial consolidation of the lesion, solid nodules, “pomegranate sign”, and “rime sign” were rare. One (2.9%) patient had pleural effusion and mediastinal lymphadenectasis. Also, only five patients underwent chest X-ray; two showed a positive result for X-ray; four patients reported negative results for chest CT scan, and two of them showed multiple GGO during re-examination after three days.
Table 2
Imaging findings of patients with COVID-19
Area of lession |
Unilateral lung | 11(32.4%) |
Bilateral lung | 23(67.6%) |
Number of lession |
single lession | 10(29.4%) |
Multiple lessions | 24(70.6%) |
Lobe of lesion distribution |
Multiple lobes | 19(55.9%) |
Two lobes | 4(11.8%) |
One lobe | 11(32.3%) |
Vascular thickening |
Yes | 29(85.3%) |
None | 5(14.7%) |
Air bronchogram sign |
Yes | 16(47.1%) |
None | 18(52.9%) |
GGO |
Yes | 29(85.3%) |
None | 5 (14.7%) |
Pulmonary consolidation |
Yes | 8(23.5%) |
None | 26(76.5%) |
Pulmonary fibrosis |
Yes | 21(61.8%) |
None | 13(38.2%) |
Interlobular septal thickening |
Yes | 29(85.3%) |
None | 5(14.7%) |
“feathery sign” |
Yes | 22(65.2%) |
None | 12 (34.8%) |
“Dandelion sign” |
Yes | 18(52.9%) |
None | 16(47.1%) |
“Pomegranate sign” |
Yes | 9(26.1%) |
None | 25(73.9.%) |
“rime sign” |
Yes | 7(20.6%) |
None | 27(79.4%) |
Solid nodule |
Yes | 3(8.8%) |
None | 31(91.2%) |
Pleural effusion |
Yes | 1(2.9%) |
None | 33(97.1%) |
Mediastinal Lymphadenopathy |
Yes | 1(2.9%) |
None | 33(97.1%) |
All patients were followed up. Among the 13 hospitalized patients, two showed rapid progression during the hospital stay and were in critical condition. Thirty 30patients were cured and discharged. Four patients had cough and chest distress on re-examination after 5-14 days. Laboratory re-examination revealed that four patients had elevated T-lymphocyte counts, accompanied by elevated alanine aminotransferase and creatinine levels. CT re-examination indicated the following: two patients had no obvious changes; eight reported improved absorption; four reported that lesions were completely absorbed, and one had mediastinal lymphadenectasis. NAT was performed in 14patients. Two patients were positive for anal swabs, while they were negative for nasal and throat swabs; the remaining 12 patients were normal, as shown in Table
3.
Table 3
Follow up 5–14 days after discharge
The mean hospitalization days | 21 |
Signs and symptoms |
Cough | 4 |
Chest distress | 4 |
Weak | 2 |
Shortness of breath | 2 |
Stomachache | 4 |
Laboratory test |
T lymphocyte count increased | 4 |
T helper cell count increased | 4 |
Cytotoxic T lymphocyte count increased | 4 |
Total bilirubin increased | 4 |
Indirect bilirubin increased | 2 |
Alanine aminotransferase increased | 4 |
Glutamic oxaloacetylase increased | 4 |
Greatinine increased | 4 |
Chest CT |
No change | 2 |
Improved absorption | 8 |
Resolution | 4 |
Mediastinal Lymphadenopathy |
None | 13 |
Yes | 1 |
Nucleic acid test by Real-time PCR |
Negative | 12 |
Positive | 2 |
Discussion
In the present study, we found that the most common CT imaging features in patients with COVID-19 were: bilateral, multifocal GGO, peripheral distribution; the predominant lower lobe; pleural effusion and lymphadenectasis were rare, which is consistent with previous reports [
6‐
8]. In addition, “feather sign”was found in 22 patients (65.2%), “dandelion sign” in 18 (52.9%), “pomegranate sign” in nine (26.1%), and “rime sign” in seven (20.6%) patients, which could be considered as new features in patients with COVID-19. The “feather sign” and “dandelion sign” on the CT image included stripe or round GGO, thickened blood vessels, and small-thickened interlobular septa. GGO shows diffuse alveolar damage under the microscope, which is histologically caused by alveoli filled with blood, pus, water, or cells [
9,
10]. The reason for the thickening of blood vessels in the lesion may be the following:under the effect of inflammatory factors, the increased permeability of the vascular wall may lead to the dilation of capillaries and the corresponding thickening of the pulmonary artery [
11]. The incidence of “feather sign” and “dandelion sign” in this study was 65.2% and 52.9%, respectively.
In this study, nine patients (26.1%) presented with “pomegranate sign”, which is an atypical chest CT feature of COVID-19. A “pomegranate sign” can be characterized as a further increase of the range of ground-glass opacity that occupies part of the lung sub-segment, the more significant thickening of the interlobular septum, complicated with a small amount of punctate alveolar hemorrhage [
9,
12], and lesions that are in imbricate arrangement, and are similar to a pomegranate. Moreover, among seven patients (20.6%) who developed a “rime sign”, two were critically ill. A “rime sign” is characterized by numerous alveolar edemas. Hemorrhagic necrosis can be observed in some alveoli. Moreover, mucus and hemorrhagic exudate diffusely cover the bronchiole wall. Microscopically, the wall thickening, small vascular proliferation, luminal stenosis, and occlusion, accompanied by interstitial infiltration of inflammatory cells, such as lymphocytes, plasma cells, and monocytes [
12], as well as numerous pulmonary interstitial fibrosis and partial hyaline degeneration are observed. This type of lesion has a wide range and looks like a white rime attached to abranch.
All patients were followed up for two weeks. Among 13 hospitalized patients, 11 had stable conditions and gradually recovered, two reported rapid progression during the hospital stay and were in critical condition, and underwent extracorporeal membrane oxygenation (ECMO). Thirty patients were cured and discharged. Fourteen underwent re-examination after 5-14 days;four had a cough, stomachache and chest distress. Very few patients developed weakness and shortness of breath. Laboratory tests revealed a significant increase in T-lymphocyte counts in four patients (flow cytometry: 762/ul, 899 /ul, respectively; the normal value was 0), accompanied by a significant increase in absolute counts of helper and cytotoxic T-lymphocytes, while alanine aminotransferase, creatinine and total bilirubin levels were increased to varying degrees, which suggested that the patient's immune function was deteriorated, and liver and renal functions were impaired; these data were consistent with previous reports [
13]. These findings suggest that liver injury may be caused by SARS-CoV-2 infection or induced by drug treatment during hospitalization.
Among patients who underwent CT re-examination, two patients showed no obvious changes; in four patients, lesions were completely absorbed; in eight cases, lesions were partially absorbed; and one had mediastinal lymphadenectasis. These data suggest that CT can be used to monitor changes during disease progression, which is consistent with the findings of Hosseiny et al [
14].
Multiple NAT (including nasal, anal, and throat swabs) were performed after 5-14 days. In two patients, the results of NAT of nasal and throat swabs were negative, while the result of NAT of the anal swab was positive, which is why the patients were immediately readmitted to the hospital for treatment. The remaining 12patients reported negative results for multiple NAT. A recent study [
15] revealed that four patients with COVID-19 showed “positive results” for nucleic acid test 5-13 days after discharge. This suggested that current discharge standards should be revised; nasal, anal, and throat swabs should be combined, as well as supplemented by a variety of other testing methods. COVID-19 patients should be monitored during treatment, rehabilitation, and quarantine, so as to fundamentally control the occurrence of the “positive results” after discharge [
16].
This study had some limitations. Firstly, no children are enrolled in this study, and the clinical, epidemiological, and imaging features of children with COVID-19 are lacking. Secondly,The number of patients collected in this study is so small that study results have certain limitations. The reliability of the conclusion needs to be further expanded to verify the sample size. Thirdly, sufficient pathological specimens are currently unavailable for comparison with imaging features. We will collect more patients data and pathological specimens to observe the evolution and outcome of the disease and determine the correlation between the imaging and pathology.
Conclusion
Our data suggested that “feather sign” and “dandelion sign” were typical chest CT features of COVID-19. “Pomegranate sign” was an atypical feature, and “rime sign” was a severe feature, which suggested poor prognosis. In clinical work, accurate identification of various chest CT signs in combination with epidemiological history, clinical features, multiple nucleic acid tests, and other testing methods can help improve the diagnostic accuracy of COVID-19 and reduce the misdiagnosis or missed diagnosis rate.
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