key: cord-346958-9eeqlkoq
authors: Caruso, Damiano; Zerunian, Marta; Polici, Michela; Pucciarelli, Francesco; Polidori, Tiziano; Rucci, Carlotta; Guido, Gisella; Bracci, Benedetta; de Dominicis, Chiara; Laghi, Andrea
title: Chest CT Features of COVID-19 in Rome, Italy
date: 2020-04-03
journal: Radiology
DOI: 10.1148/radiol.2020201237
sha: 
doc_id: 346958
cord_uid: 9eeqlkoq

BACKGROUND: The standard for diagnosis of SARS-CoV-2 virus is reverse transcription polymerase chain reaction (RT-PCR) test, but chest CT may play a complimentary role in the early detection of COVID-19 pneumonia. PURPOSE: To investigate CT features of patients with COVID-19 in Rome, Italy, and to compare the accuracy of CT with RT-PCR. METHODS: In this prospective study from March 4, 2020, until March 19, 2020, consecutive patients with suspected COVID-19 infection and respiratory symptoms were enrolled. Exclusion criteria were: chest CT with contrast medium performed for vascular indications, patients who refused chest CT or hospitalization, and severe CT motion artifact. All patients underwent RT-PCR and chest CT. Diagnostic performance of CT was calculated using RT-PCR as reference. Chest CT features were calculated in a subgroup of RT-PCR-positive and CT-positive patients. CT features of hospitalized patients and patient in home isolation were compared by using Pearson chi squared test. RESULTS: Our study population comprised 158 consecutive study participants (83 male and 75 female, mean age 57 y ±17). Fever was observed in 97/158 (61%), cough in 88/158 (56%), dyspnea in 52/158 (33%), lymphocytopenia in 95/158 (60%), increased C-reactive protein level in 139/158 (88%), and elevated lactate dehydrogenase in 128/158 (81%) study participants. Sensitivity, specificity, and accuracy of CT were 97% (60/62)[95% IC, 88-99%], 56% (54/96)[95% IC,45-66%] and 72% (114/158)[95% IC 64-78%], respectively. In the subgroup of RT-PCR-positive and CT-positive patients, ground-glass opacities (GGO) were present in 58/58 (100%), multilobe and posterior involvement were both present in 54/58 (93%), bilateral pneumonia in 53/58 (91%), and subsegmental vessel enlargement (> 3 mm) in 52/58 (89%) of study participants. CONCLUSION: The typical pattern of COVID-19 pneumonia in Rome, Italy, was peripherally ground-glass opacities with multilobe and posterior involvement, bilateral distribution, and subsegmental vessel enlargement (> 3 mm). Chest CT sensitivity was high (97%) but with lower specificity (56%).

I n P r e s s Introduction A novel coronavirus, named SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) was identified related to the new emerging viral pneumonia consequently named COVID-19 (Coronavirus Disease 2019). In accordance to the guidelines (3), the reference standard for the diagnosis of SARS-CoV-2 infection is next-generation sequencing or real-time reverse transcription polymerase chain reaction (RT-PCR) methods applied to respiratory tract specimens. However, due to intrinsic limitations (i.e. collection and transportation of samples and diagnostic kit performance), sensitivity of RT-PCR at initial presentation ranges between 60% and 71% (4-7).

As reported by Ai (5) , in a cohort of 1014 patients in Wuhan China, the sensitivity, specificity and accuracy of chest CT in the detection of COVID-19 pneumonia were 97%, 25% and 68% respectively using RT-PCR results as reference standard. Similar results were found in other studies, suggesting that CT imaging may be helpful in early detection of interstitial pneumonia in patients with high degree of suspicion for COVID-19 pneumonia (6, 8) .

Typical chest CT patterns of COVID-19 viral pneumonia include multifocal bilateral peripheral ground glass areas associated with sub-segmental patchy consolidations mostly subpleural and predominantly involving lower lung lobes and posterior segments (8) (9) (10) (11) (12) (13) (14) .

The aim of this study was to investigate chest CT features of patients with COVID-19 in Rome, Italy, and to compare the diagnostic performance of chest CT with RT-PCR.

This prospective study was approved by our local institutional review board (IRB) and written informed consent was obtained from all study participants. In case of inability of the patients to provide informed consent, it was received from the relatives or the admitting physicians who requested CT examination. 

Exclusion criteria were (a) chest CT with contrast medium performed for vascular indication (ie, pulmonary embolism, aortic dissection, coronary syndrome) , (b) patients who refused chest CT or hospitalization, (c) severe motion artifact on chest CT.

All patients underwent a prescreening questionnaire about COVID-19 symptoms in one of the six dedicated tents for COVID-19 located outside the Emergency Department collecting specific clinical information: fever, cough and dyspnea. Fever was defined with a temperature >37.5°C. Thereafter, specific blood tests (COVID-19 panel, internal disposition) and nasopharyngeal and oropharyngeal swabs were obtained for each patient. To confirm the positivity to SARS-COV2, real-time reverse transcriptase RT-PCR (Charitè, Berlin, Germany) was used (15) . All patients received two nasopharyngeal and oropharyngeal swabs at a time interval of 24 hours. Patients were considered negative after two consecutive negative RT-PCR results.

Patient demographic characteristics, clinical signs and symptoms, and laboratory results were collected. Symptomatic patients (fever >37.5°C, cough and dyspnea) with positive RT-PCR and positive CT were hospitalized, whereas patients with positive RT-PCR but negative CT (see below) and/or mild symptoms (fever ≤37.5°C, no dyspnea) were discharged for home isolation per our hospital guidelines. Data about hospitalization or home isolation were also collected.

As part of our hospital COVID-19 guidelines, after the RT-PCR swabs, all patients underwent chest CT to determine the presence or absence of viral pneumonia. All chest CT acquisitions were 

Statistical analysis was performed using SPSS version 21.0 (SPSS Inc. Chicago, IL). All continuous variables were expressed as medians and ranges and categorical variables as counts and percentages. The diagnostic performance of CT was evaluated with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy considering RT-PCR as the reference standard. CT findings for patients who required hospitalization versus home-isolation were compared by using the Pearson chi-squared test. P values of <0.05 were considered statistically significant. A 95% confidence interval was provided by the Wilson score method.

Study population comprised 158 consecutive study participants (83 male and 75 female, Table 1 .

Sixty-two/158 (39%) patients had positive RT-PCR and 102/158 (64%) patients had positive CT findings. Detailed results are reported in Table 2 

To understand the CT features of patients with COVID-19 pneumonia, a sub-analysis was performed considering only study participants with positive RT-PCR testing and chest CT findings.

Of 158 study participants, 62 participants were RT-PCR-positive and among these, 60 participants were classified as CT-positive. Considering the exclusion of two study participants due to the presence of severe chest CT motion artifact, 58 study participants were evaluated in this subanalysis ( Figure 1 Table 3 and Table 4 . Examples of chest CT findings are shown in Figures 2 and 3 .

Chest CT features were compared between patients who required hospitalization (inpatients, 49 patients) versus those patients who were referred for home isolation (outpatients, I n P r e s s 9 patients). There were no significant differences in chest CT findings between these groups ( Figure 5 , all findings p> 0.06).

To date, the majority of results evaluating the use of chest CT for COVID-19 pneumonia were of patient populations in China. We conducted a prospective study at our institution in pneumonia. There were no significant differences of chest CT features for individuals who with severe disease who were hospitalized versus those referred for mild disease referred for selfisolation, although the study size was small for this comparison (49 vs. 9 patients, respectively).

Our results are in accordance with the systematic review performed by Salehi et al (17) of 919 patients despite some interesting differences: our population showed a higher prevalence of pulmonary consolidations (72% vs 31%), GGO peripheral distribution (89% vs 76%) and ground glass opacities (100% vs 88%), respectively. Our population differs from that of Zhu et al. of 32 patients, where GGO was found in only 47% of patients with COVID-19 (19) . Recently, Chung et al analyzed a small population of 21 patients, showing a very low frequency of crazy paving pattern compared to our results (19% vs 39%, respectively) (18) . Mediastinal adenopathy was also much more frequent in our population (58%). In general, the patients in our study were somewhat older (mean, 57 years) with more men (52%) described in prior reports.

An interesting chest CT feature was the presence of enlarged subsegmental pulmonary vessels 89% of study participants. The diagnostic performance of chest CT in this study was in accordance with recently published data. Using RT-PCR as reference, we report a high sensitivity of 97%, moderate specificity of 56% and accuracy of 72%. This was similar to results from Ai et al reporting a sensitivity of 97%, specificity of 25% and accuracy of 68% in patients from Wuhan China (5) .

Several limitations should be addressed. In our setting, clinical and laboratory data were limited due to the urgency of the situation. Patient outcomes were not available at the time of this communication. The size of our patient study was limited.

In conclusion, typical pattern of COVID-19 pneumonia on chest CT in Rome, Italy was characterized by the consistent presence of peripheral ground glass opacities associated with multilobe and posterior involvement, bilateral distribution, and subsegmental vessel enlargement (>3 mm). I n P r e s s 

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