key: cord-0941333-eb8691cp
authors: Bağcı, Zafer; Keçeli, Avni Merter
title: Comparison of computed tomography (CT) findings with RT‐PCR in the diagnosis of COVID‐19 in children
date: 2021-04-26
journal: Pediatr Pulmonol
DOI: 10.1002/ppul.25426
sha: 83a9f3d58d28fe9a1c85ca7a9cff7c991fb97775
doc_id: 941333
cord_uid: eb8691cp

AIM: This study aimed to compare chest computed tomography (CT) findings with reverse‐transcription polymerase chain reaction (RT‐PCR) test results in children with probable or definitive diagnosis of coronavirus disease 2019 (COVID‐19). METHODS: In this retrospective archive study, pediatric patients who were followed up in the hospital with a possible or definitive diagnosis of COVID‐19 and who had chest CT at presentation were included. CT scan images of the patients were reinterpreted by a pediatric radiologist and compared with their RT‐PCR test results. RESULTS: Of the total of 89 patients, 33 had negative and 56 had positive RT‐PCR tests. The presence of pulmonary lesions and consolidation was statistically significantly higher in the RT‐PCR negative group than in the RT‐PCR positive group (p = 0.037 and 0.001, respectively). Lobe involvement of 0%–25% was higher in the RT‐PCR positive group (p = 0.001), and lobe involvements of 25%–50% and 50%–75% were significantly higher in the RT‐PCR negative group (p = 0.001 and 0.005, respectively). Central and perihilar involvement was found to be statistically significant in the RT‐PCR negative group (p = 0.008 and 0.005, respectively). CONCLUSION: Chest CT findings may provide some clues in predicting RT‐PCR positivity in children with a probable diagnosis of COVID‐19. Lobe involvement percentage of up to 25% is a finding in favor of patients with positive RT‐PCR test, whereas 25%–75% lobe involvement, central and perihilar involvement, and consolidation can be interpreted in favor of patients with negative RT‐PCR test.

Coronavirus disease 2019 (COVID- 19) is an acute infectious respiratory system disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged in China in December 2019 and was identified in January 2020. This infection can be transmitted by droplet, contact, or fecal-oral route. 1 Its incidence in children is less than in adults, and it has a milder clinical course. However, studies have reported that children with underlying diseases have a more severe clinical course. 2, 3 Radiological studies conducted in adults with COVID-19 infection have shown that ground-glass opacities (GGOs) and consolidation appearance, usually with peripheral distribution and bilateral multifocal lower lobe dominance, are typical chest computed tomography (CT) examination features. 4 COVID-19 reverse-transcription polymerase chain reaction (RT-PCR) results can be false negative in the early stage of the disease. Since the clinical course of pediatric patients is generally mild and chest radiography does not show all pulmonary lesions, chest CT examination may be necessary to provide supportive information. 5 In previous studies with children, chest CT findings were defined as similar but milder to the findings in adults. Usually, subpleural GGOs have been reported, and since consolidations with a halo sign are seen in up to 50% of cases, they are considered typical symptoms in pediatric patients. However, in the diagnosis of COVID- 19 , it has been recommended to evaluate radiological findings together with epidemiological data and RT-PCR results. 5, 6 In this study, it was aimed to reinterpret the CT images of pediatric patients who were followed up in the pediatric clinic with the diagnosis or prediagnosis of COVID-19 by a pediatric radiologist, and to compare the obtained findings with the RT-PCR results. It is thought that the results obtained will contribute to the early and accurate diagnosis of COVID-19 disease in children.

For this retrospective and cross-sectional study, a study permit was obtained from the local ethics committee of Health Sciences University Konya Education and Research Hospital, with the decision numbered 40-32 and dated on February 07, 2020. CT data of the patients were obtained by examining the electronic archive records of the hospital. Children aged 0-18 years who were hospitalized in the COVID-19 clinic with a possible diagnosis of COVID-19 between April 1 and July 31, 2020, who were followed up at least two times with an interval of 48 h, and who had a diagnosis of COVID-19 with a positive RT-PCR test were included in the study. Patients with deficiencies in hospital records and/or laboratory results and with immunodeficiency or any acute, chronic infectious, or inflammatory diseases were excluded from the study.

Sociodemographic data, symptoms, clinical findings, and RT-PCR results of the patients were recorded. An experienced pediatric radiologist, who was blinded to the CT reports clinical findings and RT-PCR results made previously by other radiologists, reinterpreted the noncontrast chest CT images obtained from the archive. All CT images were evaluated in terms of the presence of pulmonary lesions, lesion type, pulmonary involvement areas, and maximum lobe involvement percentage. The entire lung parenchyma area was divided into peripheral, central, and perihilar areas in all axial sections. The definition of central and peripheral areas is used to determine the location of the lesions in radiological anatomy. The lung parenchyma area is divided into three regions in axial section CT examination: The 1/3 outer part close to the costal-pleural surface is called the peripheral area. The parenchyma area between the peripheral region and the mediastinum is considered the central area ( Figure 1 ). For adults, peripheral lung tissue is defined as the 3 cm thick area close to the costal-pleural surface. However, there is no metric definition for children. In this study, the 1/3 outer part of the lung close to the costal-pleural surface is the peripheral area; 1/3 of the inner part of the lung between this area and the mediastinum was defined as the central area. In addition, the 1/3 area of the lung parenchyma around the hilus was determined as the perihilar area. [7] [8] [9] Lesions were recorded according to their placement in these specified areas. The radiological characteristics of the lesions were recorded as consolidation, GGO, halo sign, vascular fullness, nodule, and fibrosis. (Figures 2-4) . Maximum lobe involvement was defined as the percentage expression of the ratio of the total area of the lesion to the total area of the relevant lobe, regardless of the lesion type, in the lobe where the most lesion area was detected in F I G U R E 1 An 11-year-old female presented with fever and cough. She had contact with individuals infected with COVID-19 pneumonia in her family. RT-PCR test was negative. There was no pathological finding in thorax CT. Parenchymal region nomenclatures used in the study are shown in the axial thorax CT images of this case: the area around the hilus that constitutes 1/3 of the lung area was named as perihilar lung area (yellow line). The lung parenchyma between the green and yellow lines was accepted as the central area. The area extending from the outer part of the green line to the costal-pleural surface was called the peripheral area. COVID-19, coronavirus disease 2019; CT, computed tomography; RT-PCR, reverse-transcription polymerase chain reaction [Color figure can be viewed at wileyonlinelibrary.com] F I G U R E 2 A 10-year-old male patient, who was admitted with fatigue and fever and had a positive RT-PCR test, showed involvement in the left upper lobe in the axial plane unenhancement chest CT examination. The lesion with ground glass infiltration (arrows) is located in the peripheral-subpleural location. Less than 25% of the upper lobe is affected. CT, computed tomography; RT-PCR, reverse-transcription polymerase chain reaction the patient's CT examination. Percentages of involvement were determined with four degrees of involvement: 0%-25%, 25%-50%, 50%-75%, and 75%-100%. A measurement method was not used for this evaluation, the rate of involvement was determined according to the personal experience of the radiologist. Having a household member diagnosed with COVID-19.

Having a household member with fever and cough or respiratory distress with or without fever.

Having a contact history with someone diagnosed with COVID-19.

Presence of a fever or a measured temperature of 38.0°C or above.

Presence of lung auscultation findings.

Presence of tachypnea.

Presence of a new-onset cough.

Having an oxygen saturation of 92% or lower in room air.

COVID-19 RT-PCR test is requested in the following cases:

The presence of at least one of each of I and II.

The presence of at least two of the II (for each option, the relation to another option cannot be shown).

Presence of two or more people with COVID-19 diagnosis in the same household.

Babies under 9 months of age belonging to mothers diagnosed with COVID-19.

Mothers diagnosed with COVID-19 during pregnancy.

Statistical analysis was performed using the Statistical Package for Social Sciences 18.0 for Windows (SPSS Inc.). Descriptive statistics of the categorical variables were presented as frequencies and percentages, and numerical data without a normal distribution were presented as median and interquartile range (IQR). The Kolmogorov-Smirnov test was used to determine whether the age data were normally distributed or not and the Mann-Whitney U test to compare independent groups without normal distribution. The χ 2 test was used to compare the groups in terms of categorical data. All statistical analyses were performed using a two-way hypothesis with a 5% significance threshold and 95% confidence interval.

A total of 89 patients were included in the study. RT-PCR test results were positive in 56 patients and negative in 33. There was no significant difference in terms of gender between the two groups. The median ages of patients with negative and positive RT-PCR were 7 (IQR: 13) and 14 (IQR: 7) years, respectively. The age difference between the two groups was statistically significant ( Table 1) .

The presence of pulmonary lesions and consolidation were statistically significantly higher in the RT-PCR negative group than in the RT-PCR positive group (p = 0.037 and 0.001, respectively). No statistically significant difference was found between the two groups in terms of ground-glass image, halo sign, vascular fullness, and nodule/fibrosis (p = 0.126, 1.000, 0.707, and 0.201, respectively; Table 2 ).

When the two groups were compared according to the maximum lobe involvement percentage, 0%-25% lobe involvement was significantly higher in the RT-PCR positive group than in the RT-PCR negative group (p = 0.001). Lobe involvements of 25%-50% and 50%-75% were statistically significantly higher in the RT-PCR negative group than in the RT-PCR positive group (p = 0.001 and 0.005, respectively). There was no statistically significant difference between the two groups in terms of lobe involvement above 50%-75% and 75%-100% (p = 0.5281; Table 3 ).

In the comparisons made according to the localization areas of the lesions, it was found that central and perihilar involvements were higher in the RT-PCR negative group (p = 0.008 and 0.005, respectively). There was no significant difference between the two groups in terms of peripheral and diffuse involvement (p = 0.074 and 1.000, respectively; Table 4 ).

Early diagnosis of COVID-19 disease, which has become a pandemic in a short time, and causes significant morbidity and mortality, is important in terms of disease control, spread prevention, and effective treatment. Epidemiological history and clinical findings are generally used to define possible cases. 10 The gold standard method used for diagnosis today is the RT-PCR test, which enables the detection of viral ribonucleic acid belonging to SARS-CoV-2. Throat swabs, sputum, lower respiratory tract secretions, stool, and blood samples are used for screening. However, the kit quality, different sampling methods, and various sample handling problems decrease the sensitivity of the RT-PCR test. In addition, the time required to complete the test poses a problem for the early treatment and control of the disease. [11] [12] [13] [14] Epidemiological studies and clinical observations have revealed that COVID-19 has a lower prevalence in children and young adults than in adults, and it is more likely to have a mild or asymptomatic course. 15 In a study, it was shown that children constitute 1%-5% of the cases of COVID-19 diagnosis so far, the disease is milder than adults, and deaths are rare. 16 Dong et al. 17 reported that of 2143 children between 1 and 18 years old who were diagnosed with COVID-19, 4% had asymptomatic, 90% mild or moderate, and 5%

severe symptoms. In our study, the average age of the RT-PCR positive group was two times higher than that of the RT-PCR negative group, regardless of gender, showing that the prevalence of COVID-19 is higher in older children.

COVID-19 disease, along with being a systemic viral infection, mainly affects the respiratory system, and lung involvement is the most important cause of mortality and morbidity associated with this disease.

The severity level of the infection is generally determined by the degree of lung involvement. Clinical and radiological findings related to pulmonary involvement are one of the determining factors especially for symptomatic patients in determining the level of clinical severity in children. 18 Today, chest CT is used as a common and routine tool in diagnosing and monitoring COVID-19. Studies conducted so far have revealed that COVID-19 pneumonia has typical chest CT imaging features. 4, 19 However, the fact that CT findings such as GGO and bilateral involvement, which are usually associated with COVID-19 pneumonia, are not specific for COVID-19 and can be seen in other viral pneumonia makes its diagnosis controversial, especially in cases where other respiratory infections are more common. 20 Poortahmasebi et al. 21 up to 25% lobe involvement is significant for RT-PCR positive patients, whereas 25%-75% lobe involvement, central and perihilar involvement, and consolidation can be interpreted in favor of RT-PCR negative patients. Future studies that have a similar methodology and will include more cases can make important contributions to the early diagnosis and treatment of children with a prediagnosis of COVID-19 by chest CT scanning.

This study has some limitations. One of them is that other disease factors were not detected in negative RT-PCR test cases. For this purpose, the determination of viral agents from respiratory tract samples by RT-PCR and comparison of these results with CT findings will further strengthen the clinical and radiological interpretation of the diagnosis. The other limitation of the study is that the radiological evaluation was performed by a single pediatric radiologist.

A novel coronavirus from patients with pneumonia in China

World Health Organization

The continuing 2019-nCoV epidemic threat of novel coronaviruses to global health-the latest 2019 novel coronavirus outbreak in Wuhan, China

Initial CT findings and temporal changes in patients with the novel coronavirus pneumonia (2019-nCoV): a study of 63 patients in Wuhan, China

Clinical and CT features in pediatric patients with COVID-19 infection: different points from adults

Chest computed tomography in children with COVID-19 respiratory infection

Characteristics of chest CT images in patients with COVID-19 pneumonia in London

Fishman's pulmonary diseases and disorders, 2-volume set

Diagnostic yield of fiberoptic bronchoscopy in evaluating solitary pulmonary nodules

Republic of Turkey Ministry of Health General Directorate of Public Health SAB. Covid-19 (Sars-Cov-2 infection) child patient management and treatment

Diagnosis, treatment and prevention methods of pediatric COVID-19 infection

Epidemiology and clinical presentations of the four human coronaviruses 229E, HKU1, NL63, and OC43 detected over 3 years using a novel multiplex real-time PCR method

Diagnosis and treatment recommendations for pediatric respiratory infection caused by the 2019 novel coronavirus

Real-time RT-PCR in COVID-19 detection: issues affecting the results

Higher prevalence of asymptomatic or mild COVID-19 in children, claims and clues

Systematic review of COVID-19 in children shows milder cases and a better prognosis than adults

Epidemiology of COVID-19 among children in China

Updated diagnosis, treatment and prevention of COVID-19 in children: experts' consensus statement (condensed version of the second edition)

CT imaging features of 2019 novel coronavirus (2019-nCoV)

Diagnostic performance of chest CT to differentiate COVID-19 pneumonia in non-high-epidemic area in Japan

Clinical performance of RT-PCR and chest CT scan for Covid-19 diagnosis; a systematic review

Coronavirus disease 2019 (COVID-19) CT findings: a systematic review and meta-analysis

Clinical characteristics of coronavirus disease 2019 in China

Correlation of chest CT and RT-PCR testing for coronavirus disease 2019 (COVID-19) in china: a report of 1014 cases

A systematic review and metaanalysis of children

COVID-19 in 7780 pediatric patients: a systematic review

How to cite this article: Bağcı Z, Keçeli AM. Comparison of computed tomography (CT) findings with RT-PCR in the diagnosis of COVID-19 in children

The authors thank the contributors to this study.

The authors declare that there are no conflict of interests.

Zafer Bağcı: conceptualization (lead); data curation (equal); formal analysis (lead); investigation (lead); methodology (lead); project administration (lead); resources (lead); supervision (lead); validation (equal); writing original draft (lead); writing review and editing (lead).Avni Merter Keçeli: conceptualization (supporting); data curation (equal); formal analysis (supporting); investigation (supporting); methodology (supporting); project administration (supporting); resources (supporting); supervision (supporting); validation (equal); writing original draft (supporting); writing review and editing (supporting).

The data that support the findings of this study are openly available