COVID-19: Typical imaging findings in an RT-PCR confirmed symptomatic patient

date : 13.04.2020

* Alexandra Boyapati
** Tsvetomir Karagechev
** Galina Kirova-Nedyalkova
* Kameliya Genova

Department of Radiology, UMHATEM “N. I. Pirogov”, Sofia, Bulgaria Department of Radiology, Acibadem City Clinic Tokuda Hospital, Sofia, Bulgaria

alexandraboyapati@gmail.com

Keywords: COVID-19, Radiography, Computed Tomography, Viral pneumonia, RT-PCR

Clinical history: A 63-year-old female patient presented with dyspnea, dry cough and chest pain. Fever-37.3C. Positive RT-RCR test from a week ago. Oral antibiotic therapy with Clarithromycin was prescribed. Medical history of Hodgkin Lymphoma. Laboratory studies: CRP -13,22 mg/dL, ESR – 95mm/h, Leu 20,67 G/L, Ly - 4,3%, LDH 278 U/L, D-Dimer 3139 ng/ml, (+) COVID-19 IgM/IgG Rapid Test.

Imaging findings:

CXR demonstrated increased density of the lung fields with multiple, diffusely distributed ill-defined, oval-shaped ground-glass opacities with tendency towards confluence in the peripheral zones. Prominent coarse interstitial reticular pattern with well-defined distal branches of the bronchi in the lower lung fields were noted. There was no evidence of pleural effusion. (Fig.1)Lung NECT scan showed multiple ill-defined, oval-shaped ground-glass opacities in the lung parenchyma. These demonstrated bilateral, peripheral and subpleural distribution.(Fig.2,3) Typically for viral pneumonia caused by SARS-CoV2, the CT scan showed a crazy-paving pattern (GGOs and inter-/intra-lobular septal thickening) as well as the reverse halo sign.(Fig.4) In the lower lung segments, there were peripherally distributed linear reticular changes, distanced from the pleural surface - a pattern typical of organizing pneumonia.(Fig,5,6,7,8) The CT scan showed no evidence of a pleural effusion or mediastinal lymphadenopathy.

Final diagnosis: The imaging pattern of parenchymal involvement was characteristic for atypical pneumonia – viral pneumonia, caused by Coronavirus (SARS –CoV2) – COVID-19.

Discussion:

The RT-PCR test for the detection of nucleic acid from SARS-CoV-2 (RNA) in specimens obtained by nasopharyngeal swab, oropharyngeal swab, tracheal aspirate or bronchoalveolar lavage is highly specific and is considered to be the only method for definite diagnosis. The scientific data in the available literature about the test’s sensitivity is variable and lower in comparison to the CT scan, which is widely used not only in the initial evaluation of pulmonary involvement in symptomatic patients, but also in the correction of false-negative laboratory results in cases where pneumonia is suspected. Despite its lower sensitivity, chest radiography is typically the first imaging modality used for patients with suspected COVID-19. Because of the risk of contamination, portable radiography units are preferred or in some cases – the use of a unit, designated specifically for the triage zone in the emergency department. The most frequent CXR findings are peripherally distributed, ill-defined ground-glass opacities and consolidation. Typical CT findings are bilateral, multiple ground-glass opacities with peripheral distribution, crazy paving appearance (GGOs and inter-/intra-lobular septal thickening), consolidations with air-bronchograms and imaging findings in keeping with organizing pneumonia. Pleural effusion and mediastinal lymphadenopathy are not typical CT findings in COVID-19 but can still be seen in patients with co-existing lung disease.

Differential diagnosis:

A viral pneumonia with different etiology; in asymptomatic patients without a relevant epidemiological medical history – ANCA vasculitis and other diseases characterized by a ground-glass opacity pattern on imaging.

Take home messages:

In the setting of the COVID-19 pandemic, medical imaging, especially the highly sensitive CT scan is widely used in the evaluation of symptomatic patients. We believe that the ability to recognize and understand patterns of abnormalities, especially combined with the corresponding clinical and paraclinical data, will have an increasingly important role in the diagnosis of COVID-19.

Bibliography:

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