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LitCovid-sentences  

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Id Subject Object Predicate Lexical cue
T1 0-51 Sentence denotes Coronavirus disease 2019: initial chest CT findings
T2 53-61 Sentence denotes Abstract
T3 62-72 Sentence denotes Objectives
T4 73-297 Sentence denotes To systematically analyze CT findings during the early and progressive stages of natural course of coronavirus disease 2019 and also to explore possible changes in pulmonary parenchymal abnormalities during these two stages.
T5 299-306 Sentence denotes Methods
T6 307-562 Sentence denotes We retrospectively reviewed the initial chest CT data of 62 confirmed coronavirus disease 2019 patients (34 men, 28 women; age range 20–91 years old) who did not receive any antiviral treatment between January 21 and February 4, 2020, in Chongqing, China.
T7 563-721 Sentence denotes Patients were assigned to the early-stage group (onset of symptoms within 4 days) or progressive-stage group (onset of symptoms within 4–7 days) for analysis.
T8 722-835 Sentence denotes CT characteristics and the distribution, size, and CT score of pulmonary parenchymal abnormalities were assessed.
T9 837-844 Sentence denotes Results
T10 845-1097 Sentence denotes In our study, the major characteristic of coronavirus disease 2019 was ground-glass opacity (61.3%), followed by ground-glass opacity with consolidation (35.5%), rounded opacities (25.8%), a crazy-paving pattern (25.8%), and an air bronchogram (22.6%).
T11 1098-1181 Sentence denotes No patient presented cavitation, a reticular pattern, or bronchial wall thickening.
T12 1182-1302 Sentence denotes The CT scores of the progressive-stage group were significantly greater than those of the early-stage group (p = 0.004).
T13 1304-1315 Sentence denotes Conclusions
T14 1316-1461 Sentence denotes Multiple ground-glass opacities with consolidations in the periphery of the lungs were the primary CT characteristic of coronavirus disease 2019.
T15 1462-1523 Sentence denotes CT score can be used to evaluate the severity of the disease.
T16 1524-1643 Sentence denotes If these typical alterations are found, then the differential diagnosis of coronavirus disease 2019 must be considered.
T17 1645-1655 Sentence denotes Key Points
T18 1656-1769 Sentence denotes • Multiple GGOs with consolidations in the periphery of the lungs were the primary CT characteristic of COVID-19.
T19 1770-1851 Sentence denotes • The halo sign may be a special CT feature in the early-stage COVID-19 patients.
T20 1852-1953 Sentence denotes • Significantly increased CT score may indicate the aggravation of COVID-19 in the progressive stage.
T21 1955-1967 Sentence denotes Introduction
T22 1968-2227 Sentence denotes Since December 2019, an increasing number of pneumonia cases caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, Hubei, China, and subsequently, an outbreak of coronavirus disease 2019 (COVID-19) swept the globe [1–4].
T23 2228-2392 Sentence denotes As of February 3, 2020, more than 23,214 suspected cases and 20,438 confirmed cases have been identified, and there has been over 425 deaths related to the illness.
T24 2393-2452 Sentence denotes Moreover, the virus is still spreading at an alarming rate.
T25 2453-2570 Sentence denotes In this sudden epidemic, reverse transcription polymerase chain reaction (RT-PCR) revealed the cause of the outbreak.
T26 2571-2666 Sentence denotes The SARS-CoV-2 can be specifically detected in respiratory secretions or plasma samples RT-PCR.
T27 2667-2895 Sentence denotes However, some patients with likely COVID-19 may have negative initial RT-PCR results for COVID-19, which may be due to insufficient cellular material for detection or improper extraction of nucleic acids from clinical materials.
T28 2896-3194 Sentence denotes Thus, imaging examination, which can effectively and conveniently observe the pulmonary parenchymal abnormalities, can solve some challenges associated with clinical diagnosis in suspected patients with a false-negative result, especially symptomatic patients with dyspnea and respiratory distress.
T29 3195-3318 Sentence denotes Because this infection is caused by the unprecedented SARS-CoV-2, few related imaging studies have been currently reported.
T30 3319-3465 Sentence denotes Among the studies that have been conducted, multifocal consolidation or ground-glass opacity (GGO) was observed on chest radiographs and CT [5–7].
T31 3466-3845 Sentence denotes However, the sensitivity of chest radiographs for pneumonia are relatively low, and it is difficult to use chest radiographs to distinguish COVID-19 from common pneumonia during the cold season and pneumonia caused by other coronaviruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) infections [8].
T32 3846-3931 Sentence denotes In addition, the disease is developing rapidly and the symptoms of this disease vary.
T33 3932-4199 Sentence denotes Hence, it is very necessary to systematically analyze the chest CT findings associated with this disease systematically, for the timely isolation, COVID-19 RT-PCR and respiratory care of patients, and early implementation of infection prevention and control measures.
T34 4200-4473 Sentence denotes To fully understand and early discriminate the CT features of this disease in its early stages, we collected initial chest CT data from confirmed COVID-19 patients who did not receive any antiviral treatment mainly from Chongqing Three Gorges Central Hospital for analysis.
T35 4474-4757 Sentence denotes The Chongqing Three Gorges Central Hospital, located in the northeast of Chongqing and connected to Hubei Province, is one of the designated hospitals for the centralized treatment of pneumonia patients infected by the SARS-CoV-2 and has received a large number of COVID-19 patients.
T36 4758-4992 Sentence denotes Therefore, our aim was to systematically analyze the CT features of the early and progressive stages of the natural course of COVID-19 and explore the possible pathological changes in the lung during different periods of this disease.
T37 4994-5015 Sentence denotes Materials and methods
T38 5017-5035 Sentence denotes Study participants
T39 5036-5275 Sentence denotes This retrospective study was approved by the Institutional Ethics Committee of Chongqing Three Gorges Central Hospital and the Second Affiliated Hospital of Chongqing Medical University, and the requirement for informed consent was waived.
T40 5276-5520 Sentence denotes Between January 21 and February 4, 2020, totally 72 patients of confirmed COVID-19 were enrolled, i.e., 66 patients from Chongqing Three Gorges Central Hospital and 6 patients from the Second Affiliated Hospital of Chongqing Medical University.
T41 5521-5742 Sentence denotes All patients with COVID-19 were diagnosed according to the World Health Organization (WHO) interim guidance [9] and were eventually confirmed by a positive result for RT-PCR analysis of the respiratory secretions samples.
T42 5743-5913 Sentence denotes Confirmed patients were eligible if they experienced symptoms within 7 days, underwent an initial chest CT examination, and they had not received any antiviral treatment.
T43 5914-6163 Sentence denotes The exclusion criteria were as follows: (1) patients who recently experienced clinically defined pulmonary infection attributable to other pathogens, (2) patients with severe artifacts on CT images, and (3) patients whose age was less than 18 years.
T44 6164-6333 Sentence denotes According to the exclusion criteria, 7 patients who had pulmonary infections caused by other pathogens and 3 patients whose CT images had severe artifacts were excluded.
T45 6334-6491 Sentence denotes Finally, 62 confirmed COVID-19 patients (34 men, 28 women; age range 20–91 years old) who had not received antiviral treatment were retrospectively reviewed.
T46 6492-6555 Sentence denotes The workflow of COVID-19 patients selection is shown in Fig. 1.
T47 6556-6680 Sentence denotes Most cases had a history of SARS-CoV-2 exposure, in the absence of medical staff or family clusters of SARS-CoV-2 infection.
T48 6681-6816 Sentence denotes The main symptom of patients was fever, and secondary symptoms included cough, expectoration, dizziness, nasal congestion, and myalgia.
T49 6817-7155 Sentence denotes According to the changes in this disease over time [10, 11], in our study, we defined patients with an onset of symptoms within 4 days as the early-stage group (18 men, 16 women; age range 20–72 years old) and patients with an onset of symptoms within 5–7 days as the progressive-stage group (16 men, 12 women; age range 22–91 years old).
T50 7156-7377 Sentence denotes All patients underwent CT scans and laboratory examinations for C-reactive protein (CRP), white blood cell count, neutrophil count, lymphocyte count, platelet count, hemoglobin level, and procalcitonin level on admission.
T51 7378-7435 Sentence denotes Fig. 1 The workflow of coronavirus disease 2019 selection
T52 7437-7456 Sentence denotes CT data acquisition
T53 7457-7654 Sentence denotes Designated independent operating rooms were used to perform the CT examinations of all confirmed patients and after each examination; the operating room was sterilized with air disinfection method.
T54 7655-7995 Sentence denotes The initial chest CT data of 56 patients from Chongqing Three Gorges Central Hospital were obtained by using a 16-slice spiral CT scanner (Emotion 16 VC20B, Siemens Healthcare GmbH) with the following scanning protocol: a tube voltage of 120 kV, smart mA tube current modulation, a slice thickness of 1.5 mm, and a detector width of 1.5 mm.
T55 7996-8384 Sentence denotes The initial chest CT data of the other 6 patients from the Second Affiliated Hospital of Chongqing Medical University were obtained by using a 128-slice spiral CT scanner (Ingenuity CT, Philips Healthcare) with a similar scanning protocol: a tube voltage of 120 kV, smart mA tube current modulation, a matrix size of 512 × 512, a slice thickness of 1 mm, and a detector width of 0.625 mm.
T56 8385-8544 Sentence denotes All patients were scanned in the supine position and at the suspended end-inspiratory volume, and the entire lung was scanned from the apex to the bottom [12].
T57 8545-8717 Sentence denotes To reduce discrepancies in the image acquisition parameters attributable to the different CT scanners, we resampled all voxels at 1.0 × 1.0 × 1.0 mm3 before image analysis.
T58 8718-8849 Sentence denotes The multiplanar reconstruction (MPR) technique was performed to better observe images at the postprocessing station when necessary.
T59 8851-8867 Sentence denotes CT data analysis
T60 8868-9423 Sentence denotes All CT findings were described according to the Fleischner Society recommendations and defined as follows: GGO (appears as hazy increased opacity in the lung, with the preservation of bronchial and vascular margins), consolidation (appears as a homogeneous increase in pulmonary parenchymal attenuation that obscures the margins of vessels and airway walls), a crazy-paving pattern (appears as thickened interlobular septa and intralobular lines superimposed on a background of GGO), and a halo sign (appears as GGO surrounding a nodule or mass) [13, 14].
T61 9424-9804 Sentence denotes Attention was paid to CT images with GGO, consolidation, GGO with consolidation, a reticular pattern, nodules, rounded opacities, cavitation, a crazy-paving pattern, an air bronchogram, a halo sign, bronchial wall thickening, a subpleural curvilinear line, and pulmonary fibrosis, and the presence, distribution, and size of these CT characteristics were assessed in all subjects.
T62 9805-9993 Sentence denotes In addition, the presence of thoracic lymphadenopathy (lymph node size of greater than or equal to 10 mm in the short-axis dimension) and pleural effusion or thickening were also recorded.
T63 9994-10231 Sentence denotes The distribution of each finding was classified as follows: central (predominantly in the inner two-thirds of the lung), peripheral (predominantly in the outer third of the lung), and diffuse (indications in multiple lung segments) [15].
T64 10232-10385 Sentence denotes Calculation of the CT score, a semiquantitative evaluation method, was applied to quantify the extent of COVID-19 according to previous studies [15, 16].
T65 10386-10667 Sentence denotes First, the scope of the lesions in each lobe was estimated and a score of 0 (none), 1 (affecting less than 5% of the lobe), 2 (affecting 5–25% of the lobe), 3 (affecting 26–49% of the lobe), 4 (affecting 50–75% of the lobe), or 5 (affecting more than 75% of the lobe) was assigned.
T66 10668-10744 Sentence denotes Second, the CT score was obtained by adding up the scores of the five lobes.
T67 10745-10804 Sentence denotes For each patient, the CT score was in the range of 0 to 25.
T68 10805-10971 Sentence denotes All CT scans were independently reviewed and assessed by two chest radiologists (Z.F. and L.L.C., who had 18 years of experience in thoracic radiology, respectively).
T69 10972-11047 Sentence denotes Disagreements in reader interpretation were settled by consensus agreement.
T70 11049-11069 Sentence denotes Statistical analysis
T71 11070-11184 Sentence denotes All of the data were analyzed with statistical software (SPSS statistical package, version 19.0; IBM Corporation).
T72 11185-11357 Sentence denotes Continuous variables were expressed as means ± standard deviations or median (interquartile range (IQR)), and categorical variables were presented as numbers (percentages).
T73 11358-11432 Sentence denotes Kolmogorov-Smirnov tests were applied to check the normality of variables.
T74 11433-11498 Sentence denotes Mann-Whitney U tests were used for non-normally distributed data.
T75 11499-11558 Sentence denotes Two-sample t tests were used for normally distributed data.
T76 11559-11646 Sentence denotes Chi-square tests or Fisher’s exact tests were applied to compare categorical variables.
T77 11647-11939 Sentence denotes Spearman’s correlation was performed to analyze the relationship between clinical variables (age, fever, CRP, white blood cell count, neutrophil count, lymphocyte count, platelet count, hemoglobin level, and procalcitonin level) and CT variables (maximum diameter of the lesion and CT score).
T78 11940-12031 Sentence denotes For all test results, a p value of less than 0.05 was considered statistically significant.
T79 12033-12040 Sentence denotes Results
T80 12042-12108 Sentence denotes Demographic and clinical characteristics of patients with COVID-19
T81 12109-12210 Sentence denotes The demographic and clinical characteristics of all patients with COVID-19 are summarized in Table 1.
T82 12211-12368 Sentence denotes Among all 62 patients, 51 (82.3%) patients had a confirmed history of SARS-CoV-2 exposure, 43 (69.4%) patients had fever, and mainly low-grade fever (46.8%).
T83 12369-12651 Sentence denotes There were no significant differences in terms of age, sex, and laboratory test results (CRP, white blood cell count, neutrophil count, lymphocyte count, platelet count, hemoglobin level, procalcitonin level) between the early-stage group and progressive-stage group (all p > 0.05).
T84 12652-12745 Sentence denotes Table 1 Demographic and clinical characteristics between two groups in patients with COVID-19
T85 12746-12823 Sentence denotes Variables Early-stage group (n = 34) Progressive-stage group (n = 28) p value
T86 12824-12835 Sentence denotes Demographic
T87 12836-12884 Sentence denotes   Age, (years) 44.32 ± 13.53 50.82 ± 13.23 0.062
T88 12885-12923 Sentence denotes   Male 18 (52.9%) 16 (57.1%) 0.741 (χ)
T89 12924-12950 Sentence denotes Exposure history 0.494 (χ)
T90 12951-12983 Sentence denotes   Positive 27 (79.4%) 24 (85.7%)
T91 12984-13013 Sentence denotes   Negative 4 (11.8%) 1 (3.6%)
T92 13014-13042 Sentence denotes   Unknown 3 (8.8%) 3 (10.7%)
T93 13043-13051 Sentence denotes Symptoms
T94 13052-13096 Sentence denotes   Fever (°C) 37.70 ± 0.73 37.66 ± 0.94 0.854
T95 13097-13139 Sentence denotes   < 37.4 °C 8 (23.5%) 11 (39.3%) 0.064 (χ)
T96 13140-13173 Sentence denotes   37.4–38 °C 20 (58.8%) 9 (32.1%)
T97 13174-13206 Sentence denotes   38.1–39 °C 4 (11.8%) 6 (21.4%)
T98 13207-13237 Sentence denotes   39.1–41 °C 2 (5.9%) 2 (7.1%)
T99 13238-13254 Sentence denotes Laboratory tests
T100 13255-13311 Sentence denotes   CRP (mg/L) 15.98 (1.78–55.98) 35.62 (5.63–63.04) 0.329
T101 13312-13376 Sentence denotes   White blood cell count (× 109/L) 5.78 ± 1.93 6.24 ± 3.55 0.518
T102 13377-13435 Sentence denotes   Neutrophil count (× 109/L) 0.71 ± 0.13 0.74 ± 0.11 0.343
T103 13436-13494 Sentence denotes   Lymphocyte count (× 109/L) 1.04 ± 0.49 0.97 ± 0.46 0.541
T104 13495-13557 Sentence denotes   Platelet count (× 109/L) 180.79 ± 66.83 190.18 ± 73.91 0.602
T105 13558-13609 Sentence denotes   Hemoglobin (g/dL) 13.72 ± 1.79 13.69 ± 1.80 0.956
T106 13610-13673 Sentence denotes   Procalcitonin (ng/mL) 0.05 (0.04–0.07) 0.07 (0.04–0.11) 0.234
T107 13674-13733 Sentence denotes COVID-19, coronavirus disease 2019; CRP, C-reactive protein
T108 13735-13772 Sentence denotes CT findings in patients with COVID-19
T109 13773-13903 Sentence denotes The CT findings of patients with COVID-19 in early and progressive stages are listed in Table 2 and shown in Figs. 2, 3, 4, and 5.
T110 13904-13999 Sentence denotes In terms of CT characteristics, the major finding was the GGO in 38 (61.3%) of the 62 patients.
T111 14000-14526 Sentence denotes In addition, GGO with consolidation was observed in 22 (35.5%) patients; rounded opacities were observed in 16 (25.8%) patients; a crazy-paving pattern was observed in 16 (25.8%) patients; an air bronchogram was observed in 14 (22.6%) patients; a halo sign was observed in 7 (11.3%) patients; a subpleural curvilinear line was observed in 6 (9.7%) patients; pleural effusion was observed in 2 (3.2%) patients; and consolidation, nodules, thoracic lymphadenopathy, and pulmonary fibrosis were observed in 1 (1.6%) patient each.
T112 14527-14610 Sentence denotes No patient presented cavitation, a reticular pattern, or bronchial wall thickening.
T113 14611-14762 Sentence denotes Between the early-stage group and progress-stage group, there were no significant differences in the CT findings, except for the halo sign (p = 0.013).
T114 14763-14856 Sentence denotes Specifically, the halo sign was found in only the early-stage group in 20.6% of the patients.
T115 14857-14946 Sentence denotes Table 2 Comparison of CT findings and scores between two groups in patients with COVID-19
T116 14947-15024 Sentence denotes Variables Early-stage group (n = 34) Progressive-stage group (n = 28) p value
T117 15025-15036 Sentence denotes CT findings
T118 15037-15091 Sentence denotes   Ground-glass opacity 22 (64.7%) 16 (57.1%) 0.543 (χ)
T119 15092-15133 Sentence denotes   Consolidation 1 (2.9%) 0 (0%) 1.000 (χ)
T120 15134-15207 Sentence denotes   Ground-glass opacity with consolidation 11 (32.4%) 11 (39.3%) 0.570 (χ)
T121 15208-15233 Sentence denotes   Reticular pattern 0 0 –
T122 15234-15263 Sentence denotes   Nodule 1 (2.9%) 0 1.000 (χ)
T123 15264-15314 Sentence denotes   Rounded opacities 10 (29.4%) 6 (21.4%) 0.475 (χ)
T124 15315-15333 Sentence denotes   Cavitation 0 0 –
T125 15334-15386 Sentence denotes   Crazy-paving pattern 8 (23.5%) 8 (28.6%) 0.652 (χ)
T126 15387-15434 Sentence denotes   Air bronchogram 8 (23.5%) 6 (21.4%) 0.844 (χ)
T127 15435-15468 Sentence denotes   Halo sign 7 (20.6%) 0 0.013 (χ)
T128 15469-15502 Sentence denotes   Bronchial wall thickening 0 0 –
T129 15503-15561 Sentence denotes   Subpleural curvilinear line 4 (11.8%) 2 (7.1%) 0.681 (χ)
T130 15562-15609 Sentence denotes   Thoracic lymphadenopathy 0 1 (3.6%) 0.452 (χ)
T131 15610-15670 Sentence denotes   Pleural effusion or thickening 1 (2.9%) 1 (3.6%) 1.000 (χ)
T132 15671-15712 Sentence denotes   Pulmonary fibrosis 0 1 (3.6%) 0.452 (χ)
T133 15713-15772 Sentence denotes   Max diameter of lesion (cm) 4.27 ± 2.66 5.83 ± 3.76 0.059
T134 15773-15803 Sentence denotes     < 1 cm 0 1 (3.6) 0.201 (χ)
T135 15804-15837 Sentence denotes     1–2.9 cm 13 (38.2%) 5 (17.9%)
T136 15838-15872 Sentence denotes     3–4.9 cm 12 (35.3%) 10 (35.7%)
T137 15873-15904 Sentence denotes     > 5 cm 9 (26.5%) 12 (42.9%)
T138 15905-15917 Sentence denotes Distribution
T139 15918-15955 Sentence denotes   Central 1 (2.9%) 1 (3.6%) 0.961 (χ)
T140 15956-15989 Sentence denotes   Peripheral 12 (35.3%) 9 (32.1%)
T141 15990-16041 Sentence denotes   Both central and peripheral 21 (61.8%) 18 (64.3%)
T142 16042-16080 Sentence denotes CT score 4.79 ± 2.76 7.79 ± 4.62 0.004
T143 16081-16118 Sentence denotes   0–5 27 (79.4%) 10 (35.7%) 0.004 (χ)
T144 16119-16146 Sentence denotes   6–10 6 (17.6%) 12 (42.9%)
T145 16147-16166 Sentence denotes   11–15 0 3 (10.7%)
T146 16167-16192 Sentence denotes   > 15 1 (2.9%) 3 (10.7%)
T147 16193-16227 Sentence denotes COVID-19, coronavirus disease 2019
T148 16228-16524 Sentence denotes Fig. 2 A 56-year-old male with coronavirus disease 2019 in the early-stage group. a Axial non-contrast CT shows ground-glass opacities in the anterior segments of bilateral upper lobes. b Ground-glass opacity is also shown in the peripheral region of the lateral basal segment of left lower lobe.
T149 16525-16604 Sentence denotes CT score = 1 (right upper lobe) + 1 (left upper lobe) + 1 (left lower lobe) = 3
T150 16605-17025 Sentence denotes Fig. 3 A 34-year-old female with coronavirus disease 2019 in the early-stage group. a Axial non-contrast CT shows halo sign in the dorsal segment of left lower lobe and multiple ground-glass opacities in the right upper lobe and the dorsal segment of the right lower lobe. b Sagittal non-contrast CT demonstrates multiple ground-glass opacities with consolidations in the right lung, mainly distributed in the periphery.
T151 17026-17106 Sentence denotes CT score = 2 (right upper lobe) + 2 (right lower lobe) + 1 (left lower lobe) = 5
T152 17107-17471 Sentence denotes Fig. 4 A 40-year-old female with coronavirus disease 2019 in the progressive-stage group. a Axial non-contrast CT shows crazy-paving pattern in the anterior segment and consolidation in the posterior segment of right upper lobe. b Consolidations are noted in the bilateral lower lobes mainly in the peripheral regions, accompanied with subpleural curvilinear line.
T153 17472-17599 Sentence denotes CT score = 3 (right upper lobe) + 1 (right middle lobe) + 3 (right lower lobe) + 1 (left upper lobe) + 3 (left lower lobe) = 11
T154 17600-17928 Sentence denotes Fig. 5 A 60-year-old male with coronavirus disease 2019 in the progressive-stage group. a Axial non-contrast CT in pulmonary window shows diffuse ground-glass opacities with consolidations in bilateral lungs. b Axial non-contrast CT in mediastinal window shows consolidations in bilateral lungs, with bilateral pleural effusion.
T155 17929-18056 Sentence denotes CT score = 5 (right upper lobe) + 4 (right middle lobe) + 4 (right lower lobe) + 3 (left upper lobe) + 2 (left lower lobe) = 18
T156 18057-18413 Sentence denotes In terms of lesion size, lesions with a maximum diameter greater than 5 cm were found in 21 (33.9%) of 62 patients; lesions with a maximum diameter of 3–4.9 cm were found in 22 (35.5%) patients; lesions with a maximum diameter of 1–2.9 cm were found in 18 (29.0%) patients; and lesions with a maximum diameter less than 1 cm were found in 1 (1.6%) patient.
T157 18414-18540 Sentence denotes There was no statistically significant difference in lesion size between the two groups of patients with COVID-19 (p = 0.059).
T158 18541-18872 Sentence denotes Regarding the distribution of pulmonary parenchymal abnormalities, lesions that were mainly distributed in both the central and peripheral lung regions accounted for 62.9%; lesions distributed in the peripheral lung were present in 21 (33.9%) patients; and lesions distributed in the central lung were present in 2 (3.2%) patients.
T159 18873-19043 Sentence denotes There was no statistically significant difference in the distribution of pulmonary parenchymal abnormalities between the two groups of patients with COVID-19 (p = 0.961).
T160 19045-19079 Sentence denotes CT score of patients with COVID-19
T161 19080-19214 Sentence denotes The CT scores of all patients with COVID-19 are shown in Table 2 and the CT scores of each lobe in the two groups are shown in Fig. 6.
T162 19215-19335 Sentence denotes The CT scores of the progressive-stage group were significantly greater than those of the early-stage group (p = 0.004).
T163 19336-19507 Sentence denotes In the early-stage group, 27 (79.4%) patients had CT scores in the range of 0–5, 6 (17.6%) patients had CT scores of 6–10, and only 1 patient had a CT score of 11 or more.
T164 19508-19732 Sentence denotes In the progressive-stage group, 10 (35.7%) patients had CT scores in the range of 0–5, 12 (42.9%) patients had CT scores of 6–10, 3 (10.7%) patients had CT scores of 11–15, and 3 (10.7%) patients had CT scores of 15 or more.
T165 19733-19818 Sentence denotes Fig. 6 The CT score of each lobe in the early-stage group and progressive-stage group
T166 19819-20140 Sentence denotes Among all 62 COVID-19 patients, the CT scores of pulmonary parenchymal abnormalities were significantly positively correlated with maximum diameter of the lesions (r = 0.531, p < 0.001), and the CT scores were also significantly positively correlated with the age of the patients (r = 0.255, p = 0.045), shown in Table 3.
T167 20141-20222 Sentence denotes Table 3 Correlation of clinical variables with CT score in patients with COVID-19
T168 20223-20241 Sentence denotes Variables CT score
T169 20242-20253 Sentence denotes Age (years)
T170 20254-20269 Sentence denotes   p value 0.045
T171 20270-20285 Sentence denotes   r value 0.255
T172 20286-20313 Sentence denotes Max diameter of lesion (cm)
T173 20314-20331 Sentence denotes   p value < 0.001
T174 20332-20347 Sentence denotes   r value 0.531
T175 20348-20382 Sentence denotes COVID-19, coronavirus disease 2019
T176 20384-20394 Sentence denotes Discussion
T177 20395-20513 Sentence denotes As reported, patients with COVID-19 usually develop clinical symptoms after an incubation period of 4.1–7.0 days [11].
T178 20514-20579 Sentence denotes After admission, chest imaging examination was performed on them.
T179 20580-20948 Sentence denotes According to the results of changes in this disease in recent studies [10, 11], the patient’s condition progressively worsens on the 3–5 days after symptom onset, and the guidelines for an imaging diagnosis of COVID-19 recommend that reviewing CT or plain radiograph is needed for suspected cases 3–5 days after diagnosis to observe changes in the disease status [12].
T180 20949-21109 Sentence denotes Thus, we assigned patients to two groups according to the time of onset of symptoms to analyze the CT findings in early-stage and progressive-stage of COVID-19.
T181 21110-21267 Sentence denotes In this study, 62 confirmed patients with COVID-19 underwent chest CT scans, and positive rate of detecting the pulmonary parenchymal abnormalities was 100%.
T182 21268-21652 Sentence denotes In addition, the CT data in our study were obtained from the initial chest CT examination of patients who had not received any antiviral therapy; these results may better reflect the degree of viral infection and the immune system status before clinical intervention and provide an important basis for clinical classification, treatment strategy development, and prognosis prediction.
T183 21653-21853 Sentence denotes In our study, the major characteristic of COVID-19 was GGO (61.3%), followed by GGO with consolidation (35.5%), rounded opacity (25.8%), a crazy-paving pattern (25.8%), and an air bronchogram (22.6%).
T184 21854-21951 Sentence denotes In contrast, pulmonary fibrosis (1.6%) and pleural effusions (3.2%) were rare on chest CT images.
T185 21952-22072 Sentence denotes These various CT findings are likely related to the complex pathological changes in the lungs of patients with COVID-19.
T186 22073-22434 Sentence denotes Although pathological changes in the lung tissue of COVID-19 patients have not yet been studied, recent studies have reported that SARS-CoV-2 is closely related (with 88% identity) to two bat-derived severe acute respiratory syndrome (SARS)–like coronaviruses, with approximately 79% homology with SARS-CoV and approximately 50% homology with MERS-CoV [17, 18].
T187 22435-22664 Sentence denotes Because the pathogenesis of viral infections in the same family may be similar, previous studies on coronaviruses may be helpful in understanding the various CT findings in COVID-19 patients based on similar pathological changes.
T188 22665-22953 Sentence denotes In SARS patients, pathological changes include injury to pulmonary epithelial cells, hyaline membrane formation on in the inner wall of the alveoli, and a large number of tissue cells and mass thrombi formed by proliferative fibrous tissue that block the small airway and air cavity [19].
T189 22954-23055 Sentence denotes These pathological changes may be the main pathological basis of the CT findings, especially the GGO.
T190 23056-23263 Sentence denotes Among all the CT findings, GGO was the most common one in both the early and progressive stages of COVID-19 and was characterized by multiple sized lesions, mainly distributed in the peripheral lung (96.8%).
T191 23264-23574 Sentence denotes An analysis of thin-section CT images of SARS patients showed that multiple GGOs were the main imaging finding (68.4%) and were distributed in the periphery of the lung (71.8%), with interlobular septal thickening (24.2%) and intralobular interstitial hyperplasia (32.2%), also called the crazy-paving pattern.
T192 23575-23649 Sentence denotes These findings are very similar to the CT manifestations of COVID-19 [20].
T193 23650-23805 Sentence denotes For pneumonia caused by MERS-CoV, GGO was also found on the chest CT images and was mainly distributed in the subpleural and basilar lung regions [21, 22].
T194 23806-23965 Sentence denotes Interestingly, pleural effusion was rare and no tree-in-bud pattern or cavitation was found in pneumonia patients infected by the three kinds of coronaviruses.
T195 23966-24065 Sentence denotes In addition, we found that only one case of COVID-19 (1.6%) presented as consolidation without GGO.
T196 24066-24244 Sentence denotes Compared with the large amount of consolidation that appears in the early stage of SARS, we speculate that the pathogenicity of SARS-CoV-2 may be less than that of SARS-CoV [23].
T197 24245-24484 Sentence denotes Thus, it is necessary to fully understand and discriminate the CT features of COVID-19 at an early stage, which is helpful for the timely isolation and respiratory care of patients and early implementation of infection prevention measures.
T198 24485-24681 Sentence denotes In addition to GGO, another important CT characteristic of COVID-19 was multiple GGOs with consolidations, accompanied by interlobular septal thickening, mainly in the peripheral part of the lung.
T199 24682-24894 Sentence denotes These basic CT features were similar to the findings reported by Huang et al, whose study showed that multiple GGOs with partial consolidation appeared bilaterally on the chest CT images of COVID-19 patients [7].
T200 24895-25068 Sentence denotes Similarly, in another chest CT study of a 33-year-old patient diagnosed with COVID-19 in Wuhan, China, multiple GGOs distributed in both the peripheral lungs were found [5].
T201 25069-25257 Sentence denotes Therefore, we suggest that multiple GGOs with consolidations mainly in the periphery of the lung are a basic CT feature of COVID-19, which is helpful for the initial screening of COVID-19.
T202 25258-25405 Sentence denotes Unexpectedly, the halo sign (20.6%) was the only significantly different CT manifestation in the early stage of COVID-19 among all the CT findings.
T203 25406-25479 Sentence denotes In our study, the halo sign appeared in only the early stage of COVID-19.
T204 25480-25651 Sentence denotes We hypothesized that the halo sign rapidly changed into GGO within 1 week due to the aggravation of COVID-19, and no other new halo sign had been formed in the short term.
T205 25652-25778 Sentence denotes In addition, there were no significant differences in the other CT findings or distribution of lesions between the two stages.
T206 25779-26114 Sentence denotes For these findings, we speculated that the speed of GGO formation was due to the damage to the alveolar epithelium caused by the virus and may be similar to that of consolidation caused by an inflammatory reaction of the lung tissue, resulting in a change in different types of lesions during the synchronous increase in opacification.
T207 26115-26349 Sentence denotes In pneumonia caused by SARS-CoV, Ooi et al found that GGO and consolidation formed in the first week of SARS-CoV infection increased in the second week, and only residual strips and reticular shadows were seen in the fourth week [15].
T208 26350-26481 Sentence denotes Therefore, the CT manifestations of COVID-19 are different at different stages, which helps the differential diagnosis of COVID-19.
T209 26482-26627 Sentence denotes Furthermore, our results showed that the CT scores in the progressive-stage group were significantly greater than those in the early-stage group.
T210 26628-26908 Sentence denotes Further analysis showed that the CT scores were positively correlated with the maximum diameters of the lesions (r = 0.531), indicating that the range of lesions in the progressive stage was larger than and the degree of inflammation was more serious than that in the early stage.
T211 26909-27072 Sentence denotes These results also showed that without any antiviral treatment, COVID-19 continued to progress 5–7 days after the onset of symptoms, without any improvement trend.
T212 27073-27215 Sentence denotes Therefore, necessary clinical measures, including antiviral and supportive therapies, should be administered to prevent disease deterioration.
T213 27216-27371 Sentence denotes Because of the lack of additional data, the correlation between the CT score and clinical classification and the prognosis of COVID-19 needs further study.
T214 27372-27475 Sentence denotes Moreover, CT scores showed a significant positive correlation with ages in all 62 patients (r = 0.255).
T215 27476-27613 Sentence denotes In a previous study on SARS, Grinblat et al considered that age was a risk factor for severe lung injury and poor prognosis of SARS [24].
T216 27614-27709 Sentence denotes Therefore, elderly patients need to be treated earlier and more actively than younger patients.
T217 27710-27744 Sentence denotes Our study had several limitations.
T218 27745-27903 Sentence denotes First, because COVID-19 is a novel disease and lacks a series and long-term CT data, we can analyze only the existing information in a retrospective analysis.
T219 27904-28088 Sentence denotes Moreover, the time of chest CT examination after symptom onset was inconsistent, so it was difficult to summarize the CT appearances that could reflect the whole course of the disease.
T220 28089-28223 Sentence denotes Second, the sample size in our study was relatively small, and there may be deviation in the comparison of the results of CT findings.
T221 28224-28299 Sentence denotes Third, most of our cases were imported cases and some were secondary cases.
T222 28300-28469 Sentence denotes Further research is needed to observe whether virus variation exists in the process of infection and whether virus variation will produce different in CT manifestations.
T223 28470-28542 Sentence denotes Finally, there was no histopathological evidence from deceased patients.
T224 28543-28703 Sentence denotes In conclusion, our study showed that chest CT examination was very effective in detecting pulmonary parenchymal abnormalities in the natural course of COVID-19.
T225 28704-28807 Sentence denotes Multiple GGOs with consolidations in the peripheral lung was the primary CT characteristic of COVID-19.
T226 28808-28989 Sentence denotes The halo sign may be a special CT feature in the early stage of COVID-19, while a significantly increased CT score may indicate the aggravation of COVID-19 in the progressive stage.
T227 28990-29129 Sentence denotes In patients with dyspnea and respiratory distress, CT examination is very effective in the preclinical screening of patients with COVID-19.
T228 29131-29147 Sentence denotes Publisher’s note
T229 29148-29266 Sentence denotes Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
T230 29268-29287 Sentence denotes Funding information
T231 29288-29380 Sentence denotes This study was supported by a grant from the Natural Science Foundation of China (81401382).
T232 29382-29415 Sentence denotes Compliance with ethical standards
T233 29417-29426 Sentence denotes Guarantor
T234 29427-29488 Sentence denotes The scientific guarantor of this publication is Wenbing Zeng.
T235 29490-29510 Sentence denotes Conflict of interest
T236 29511-29665 Sentence denotes The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
T237 29667-29690 Sentence denotes Statistics and biometry
T238 29691-29752 Sentence denotes No complex statistical methods were necessary for this paper.
T239 29754-29770 Sentence denotes Informed consent
T240 29771-29841 Sentence denotes Written informed consent was waived by the Institutional Review Board.
T241 29843-29859 Sentence denotes Ethical approval
T242 29860-29909 Sentence denotes Institutional Review Board approval was obtained.
T243 29911-29922 Sentence denotes Methodology
T244 29923-29937 Sentence denotes •Retrospective
T245 29938-29952 Sentence denotes •Observational
T246 29953-29971 Sentence denotes •Multicenter study