key: cord-0893908-n287q6vv
authors: Tabatabaei, Seyed Mohammad Hossein; Talari, Hamidreza; Moghaddas, Fahimeh; Rajebi, Hamid
title: Computed Tomographic Features and Short-term Prognosis of Coronavirus Disease 2019 (COVID-19) Pneumonia: A Single-Center Study from Kashan, Iran
date: 2020-04-20
journal: Radiol Cardiothorac Imaging
DOI: 10.1148/ryct.2020200130
sha: 3a6e824adf266253ae6be3bc38be5d6a4fb10c20
doc_id: 893908
cord_uid: n287q6vv

BACKGROUND: Radiologists play a pivotal role in the era of COVID-19 pneumonia although our knowledge of the imaging features is expeditiously evolving. PURPOSE: We assessed the CT chest features of confirmed cases from Iran, the first published report from the country. We hypothesized that certain CT features may have short-term prognostic value. MATERIALS AND METHODS: 120 consecutive symptomatic cases of COVID-19 infection who had undergone chest CT were enrolled in this retrospective study. Patients were categorized into three groups; routine inward hospitalization, ICU admission and expired based on a short-term follow-up. Detailed initial CT features and distributional evaluation were recorded. RESULTS: The mean age in the expired group was 70.7, significantly higher than the other two groups (p-value <0.05). Ninety-four percent (113/120) of the cases had ground-glass opacities (GGO). There was peripheral and lower zone predilection in majority of cases. Subpleural sparing and pleural effusion were seen in approximately twenty-three percent (28/120) and seventeen percent (20/120) of the cases respectively. The combined ICU group and expired cases had significantly more consolidation, air-bronchograms, crazy paving and central involvement of the lungs when compared to routinely hospitalized patients (all p-values < 0.05). CONCLUSION: Our study supports the previously described typical CT appearance of COVID-2019 pneumonia with bilateral GGO, in peripheral distribution and lower lung zone predilection. Subpleural sparing and pleural effusion were seen approximately in one-fifth and one-sixth of our COVID-19 cases respectively. Consolidation, air-bronchograms, central lung involvement, crazy paving and pleural effusion on initial CT chest have potential prognostic values, the features more commonly observed in critically ill patients.

Reverse transcriptase polymerase chain reaction (RT-PCR) remains the standard diagnostic reference for COVID-19 infection, but the high false-negative rate and its restricted availability limit the prompt diagnosis, which can result in a growing number of cases given the contagiousness of the virus (3). Radiologists have played an important role in the era of COVID-19, although our knowledge about the imaging features of the associated pneumonia is expeditiously evolving (4) . Imaging provides the healthcare facilities with a feasible screening tool for the detection of early pneumonia in high-risk patients. It also aids the physicians in the diagnosis before the RT-PCR results get available. Last but not least, it could be useful in assessing the severity and course of disease progression (5) . Timely recognition of the disease ensures immediate care and appropriate follow-up, and halts the disease spread in the community. Chest X-ray (CXR) is not a sensitive tool to detect viral pneumonia, as it is confirmed for COVID-19 in recent investigations (6, 7) . Therefore, computed tomography (CT) is I n p r e s s the major diagnostic radiologic tool in identifying the COVID-19 associated pneumonia among the suspected cases.

Recently performed studies suggest that CT could have higher sensitivity than RT-PCR in the diagnosis of COVID-19 associated pneumonia (8) (9) (10) . Multiple recent studies from China and South Korea revealed that ground-glass opacities (GGO) are the most common finding in COVID-19 associated pneumonia. Both lungs are involved in almost all cases and a peripheral subpleural distribution is the most reported location. Multiple other radiologic features have also been described, although imaging features are highly nonspecific (7, (11) (12) (13) (14) .

Based on Johns Hopkins Center for Systems Science and Engineering online dashboard, as of March 10, 2020 Iran is the 3 rd leading country in the number of cases and mortality rate (15) . This study is the first reported cohort of COVID-19 cases from a single academic center from Kashan, Iran, which focuses on CT findings and assesses the short-term prognosis based on the primary radiologic features.

In this retrospective research study, we aimed to review the radiologic findings in our 120 laboratory-confirmed cohort of patients with COVID-19 pneumonia, one of the few first available reports out of the center of the disease and to compare with the prior studies from

China. Furthermore, we followed the patients' clinical course up in a one to two-week period after the hospitalization for assessing the short-term prognosis. We hypothesized that certain radiologic features may be more prevalent in critically-ill and expired patients when compared to patients undergoing routine ward hospitalization.

This retrospective study got institutional review board approval and the requirement for A total of 120 symptomatic patients with confirmed COVID-19 infection (Mean age: 54.9 ± 17.07, 50 female and 70 male) were eligible to be enrolled in this study and available laboratory, radiologic, and epidemiologic data were collected. Based on a one to two-week inpatient clinical follow-up, we categorized our patients into three groups: routine ward hospitalization, intensive care unit (ICU) admission, and expired. All patients had at least one chest CT performed at initial presentation. In cases with more than one chest CT, the initial CT scan was considered for interpretation.

All CT studies were performed using a multidetector scanner (Alexion TSX-034A, Canon, Japan). A low-dose institutional protocol was applied with the detailed acquisition parameters were as follows; tube voltage: 120kVp; tube current: 50-90 mAs using automatic exposure control, slice thickness = 3mm. CT images were acquired at full inspiration with the patient in supine position, and without administration of intravenous contrast medium. The mean CTDIvol was 4.9 mGy (range: 3.9 -7.8 mGy). 

Categorical variables were presented as numbers and percentages. Differences between groups were analyzed by chi-square for categorical variables and one-way ANOVA for the continuous variables. All statistical analyses were performed with SPSS software (version 24.0, IBM Corp., Armonk, NY, USA) and p-values < 0.05 were considered statistically significant.

Of the 120 patients, 70 were male and 50 were female. The patients' ages ranged from 23 to 95 years with a mean of 54.9 ± 17.1. All patients were symptomatic with laboratory confirmation of COVID-19.

In one to two-week follow-up, 80% of patients (96/120) were hospitalized in the routine ward. Eleven patients got admitted to ICU and intubated, while 13 cases were expired. The mean age in the expired group was 70.7, significantly higher than the other two groups (p-value < 0.05). Upon complete review of patients' clinical data, we only had two immunosuppressed patients in our cohort, one in our ward hospitalization group and one in the ICU group.

Of the 120 cases, 6 patients had normal chest CTs. The CT features and distribution across the 120 reported cases are listed in Table 1 

Six asymptomatic patients had normal initial chest CT. All of them had a history of exposure to confirmed cases. This emphasizes the importance of the combination of chest CT and RT-PCR, and follow-up chest CT for timely diagnosis in clinically suspected individuals.

We also investigated the CT features in our short-term follow-up groups. Patients admitted to ICU or expired due to COVID-19 pneumonia, were significantly older and had more consolidation pattern, central involvement of the lungs (peri-bronchovascular), developed airbronchograms, had more crazy paving appearance and pleural effusion, findings which may reflect the virulence of COVID-19. Therefore, these radiologic features have the potential to represent prognostic imaging markers in patients with COVID-19 pneumonia. Our study supports the fact that critically-ill patients develop extensive consolidative opacities with air bronchograms, which is different from well-described GGOs associated with COVID-19

pneumonia, a finding which should also raise the concern when seen in CT chest. Clinically unstable patients also demonstrate a central pattern of involvement, in addition to the classic peripheral subpleural distribution. On the other hand, there is higher incidence of reverse halo sign and perilobular opacities in the stable patients, both signs representative of underlying organizing pneumonia. These finding could support higher incidence of diffuse alveolar damage in the clinically unstable patients in ICU and expired group, and higher prevalence of organizing pneumonia pattern in stable patients who were routinely hospitalized in the ward. Finally, ICU and expired patients had more cases of pleural effusion, a nonspecific finding which has also been reported more frequently in emergent cases of Zhao et al study (18) .

There are a few limitations to our study. Our cohort of cases only consisted of the hospitalized patients and may not reflect the accurate disease burden and imaging features in I n p r e s s the community. We did not evaluate follow-up CT chests in patients to assess the temporal changes in lung parenchyma during the disease course, a process that has been better evaluated in multiple studies (12, 19 and 20) . Our follow-up groups were designed based on a short-term check of the patients' clinical conditions and do not correlate with long-term prognosis. As a future direction, larger studies should be performed to evaluate the prognostic value of the initial CT features that were significantly more prevalent in our critically-ill and expired cases. Additionally, longer follow ups are warranted for the further evolution of the lung findings in COVID-2019 pneumonia which may help predict worse outcomes. We also did not assess the role of chest CT in monitoring the response to treatment.

Chest CT helps in early diagnosis, guides the physicians, providing potential prognostic markers and follow-up assessment of disease progression. Healthcare measures are evolving daily as new cases are identified. Future studies will be warranted in ascertaining how patients with COVID-19 pneumonia respond to treatment on imaging surveillance. 

Novel Coronavirus (COVID-19) situation

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Chest CT Severity Score: An Imaging Tool for Assessing Severe COVID-19

Imaging Profile of the COVID-19 Infection: Radiologic Findings and Literature Review

Chest Radiographic and CT Findings of the 2019 Novel Coronavirus Disease (COVID-19): Analysis of Nine Patients Treated in Korea

Correlation of Chest CT and RTPCR Testing in Coronavirus Disease 2019 (COVID-19) in China: A Report of 1014 Cases

Sensitivity of Chest CT for COVID-19: Comparison to RT-PCR

Chest CT for Typical 2019-nCoV Pneumonia: Relationship to Negative RT-PCR Testing

Chest CT Findings in Coronavirus Disease-19 (COVID-10): Relationship to Duration of Infection

Time Course of Lung Changes of Chest CT During Recovery From 2019 Novel Coronavirus (COVID-19) Pneumonia

CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV)

Coronavirus Disease 2019 (COVID-19): A Perspective from China

Coronavirus COVID-19 global cases

Fleischner Society: Glossary of Terms for Thoracic Imaging

Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to Duration of Infection

Relation Between Chest CT Findings and Clinical Conditions of Coronavirus Disease (COVID-19) Pneumonia: A Multicenter Study

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

Radiological findings from 81 patients with COVID-19 pneumonia in Wuhan, China: a descriptive study

SD: Standard deviation, M: Male, F: Female, RUL: Right upper lobe, RML: Right middle lobe, RLL: Right lower lobe, LUL: Left upper lobe, LLL: Left Lower Lobe, GGO: Ground-glass opacities

We would like to thank Dr. Reza Razzaghi, Dr Maedeh Najafi Zade, and Dr. Ahmad Najafi in infectious disease department and Dr. Milad Mokfi in radiology department for their assistance in data collection. I n p r e s s