key: cord-0683205-5ie4593y
authors: Hu, Xiaoyan; Gou, Jie; Guo, Liang
title: Clinical features and chest CT findings of three cases of 2019 novel coronavirus (COVID-2019) pneumonia
date: 2020-06-19
journal: Radiol Case Rep
DOI: 10.1016/j.radcr.2020.06.031
sha: d2136782336389e10391aafce9bd7d28397f1a85
doc_id: 683205
cord_uid: 5ie4593y

BACKGROUND: Since December 2019, a new type of acute respiratory disease caused by the 2019 novel coronavirus (COVID-2019) appeared to Wuhan, China. Currently, positive of virus nucleic acid in respiratory or blood samples is the gold standard for the diagnosis of the disease, but the nucleic acid test may be false negative. Chest CT examination plays an important role in diagnosis of COVID-2019 pneumonia. CASE PRESENTATION: The clinical manifestations, laboratory examination, and chest CT characteristics of 3 patients with COVID-2019 pneumonia were reported. The mainly clinical manifestation of the 3 patients was fever. white blood cell, neutrophil cell and lymphocyte cell count can be normal, only C-Reactive Protein slightly elevated. Real-time fluorescence polymerase chain reaction of throat swab detection can be negative. Chest CT showed multifocal ground-glass opacities (GGO) in the peripheral of bilateral lungs. GGOs with consolidation, air bronchogram, vascular enlargement and halo sign were be found. CONCLUSIONS: In the early stages of COVID-2019 pneumonia, the laboratory parameters may be normal, the nucleic acid test may be false negative. Chest CT examination may be helpful for diagnosis of COVID-2019 pneumonia.

Since December 2019, multiple pneumonia cases of unknown causes have occurred across Wuhan, Hubei Province, China. The epidemic disease, which had been confirmed to have been caused by a novel coronavirus through high-throughput sequencing [1] [2] [3] , has rapidly spread across the country and abroad. On 

Case 1 A 22-year-old woman, who had a history of close contact with COVID-2019 pneumonia patient, was admitted to hospital due to fever (38.6℃) and cough for 3 days. Her laboratory examination showed the normal white blood cell count, neutrophil cell count, lymphocyte cell count, and C-Reactive Protein. Real-time fluorescence polymerase chain reaction of throat swab was positive for COVID-2019.

The initial chest CT manifestation was normal. 8 days after admission, follow-up chest CT showed multifocal ground-glass opacities (GGO) in the peripheral of bilateral lungs. GGOs with consolidation, air bronchogram, vascular enlargement and halo sign were be found. After 15 days of admission, follow-up chest CT showed the consolidation was completely resolved and the halo sign was disappeared. The GGOs were partial resolution (Figure1).

Case2 A 49-year-old woman, who had a history of close contact with COVID-2019 pneumonia patient, was admitted to hospital due to a high-grade fever (38.4℃) for 6 days. Her laboratory examination showed the normal white blood cell count, 

The main clinical manifestation of COVID-2019 pneumonia was fever. White blood cell and lymphocyte count may be normal in the early stage. According to the guideline of Diagnosis and Treatment of Pneumonitis Caused by 2019-nCoV (trial sixth version) published by the China government [4] , COVID-19 diagnosis must be confirmed by the reverse transcription polymerase chain reaction (RT-PCR) or gene sequencing for respiratory or blood specimens.

However, due to the limitations of sample collection and transportation, as well as the performance of the kit, it has been reported that the overall positive rate of RT-PCR initially presented by throat swab samples is about 30% to 60%. [5] . Chest CT, as a conventional imaging tool for the diagnosis of pneumonia, is relatively easy to perform and can produce rapid diagnosis. In this context, chest CT may provide benefit for COVID-2019 diagnosis [6] . As previously reported [7] [8] [9] , almost all patients with COVID-2019 have typical chest CT features, including pure GGOs, GGOs with interstitial and/or interlobular septal thickening, GGOs with consolidation, multifocal patchy consolidation, bronchiolar wall thickening, and interlobular septal thickening, with a peripheral distribution with bilateral, multifocal lower lung involvement.

Case 1 patient who was confirmed by positive of real-time fluorescence polymerase chain reaction of throat swab for COVID-2019, was admitted to hospital due to fever.

The initial chest CT manifestation and laboratory examination were normal. However, follow-up chest CT 8 days after admission showed the relevant manifestations of COVID-2019 pneumonia including multifocal GGOs, GGOs with consolidation, air bronchogram, vascular enlargement and halo sign. The repeated CT after 15 days later of admission showed the consolidation was completely resolved and the halo sign was disappeared. Similar results have been found in previous studies [7, 10] . Chung [7] found that some patient developed GGO three days later of follow-up chest CT, whose initial chest CT were normal. While in Xu's [10] research, follow-up chest CT found that most lesions were absorbed four to ten days after treatment. This may indicate that the lesions may change in a short time, and repeated CT scans may provide evidence for clinical diagnose and treatment.

In case 2, the initial chest CT examination showed typical signs of COVID-2019 pneumonia, including multifocal GGOs with air bronchogram, interlobular septal thickening, crazy paving pattern, and halo sign in the peripheral of bilateral lower lobes, which were in consistent with previous studies [7] [8] [9] . However, the laboratory examination showed no specific abnormalities in white blood cell count, neutrophil cell count and lymphocytes cell count and only a slight increase in c-reactive protein.

The 4 times of COVID-2019 by real-time fluorescence polymerase chain reaction of throat swab were negative. The fifth time real-time fluorescence polymerase chain reaction for COVID-2019 with alveolar lavage fluid was finally confirmed to be positive. It may be due to the influence of sampling errors, laboratory testing technology and other reasons, nucleic acid testing has a certain false negative [11, 12] .Previous studies showed that the majority of cases of COVID-2019 had similar features on CT imaging, such as GGOs, GGOs with consolidation, GGOs with interstitial and/or interlobular septal thickening [7] [8] [9] and influenza involved all five lobes [14] [15] [16] . However, the COVID-19 pneumonia mainly involved peripheral part of the lung, while influenza pneumonia was more diffuse and involved both central and peripheral parts [17] . Wang et al [18] found that COVID-19 presented a distinct lesion margins and a shrinking contour compared with influenza pneumonia. And COVID-19 had a patchy or combination of GGO and consolidation opacities, while a cluster-like pattern and bronchial wall thickening were more frequently seen in influenza pneumonia. These characteristics may distinguish COVID-2019 with influenza pneumonia.

In the early stages of COVID-2019 pneumonia, the laboratory parameters and chest CT manifestation may be normal, the nucleic acid test may be false negative, and it is difficult to differentiate from chronic bronchitis or other influenza virus infections.

Therefore, doctors should combine the clinical manifestations and epidemiological history, and cannot easily exclude the COVID-2019, so as to avoid missed diagnosis and misdiagnosis of the disease, delay the treatment of patients and increase the risk of disease transmission.

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