Coronavirus disease 2019 (COVID-19) is a highly infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [11].
As of 21 May 2020, the number of cases of confirmed COVID-19 globally is over 5 million [12].
CT examination is of great significance not only in diagnosing COVID-19 but also in monitoring disease progression and evaluating therapeutic efficiency [13].
Asymptomatic infected individuals, called “asymptomatic carrier or transmitter”, may also become the contagious source of SARS-CoV-2, and some of them progress rapidly, even resulting in acute respiratory distress syndrome (ARDS) with a high case-fatality rate [4, 5].
This cross-sectional study included 44 asymptomatic patients confirmed to be infected with COVID-19 by PCR study. MSCT of the chest was done to all patients as requested. The study was conducted between March 20 and May 20, 2020, in Cairo, Egypt.
This study included 16 males and 28 females with an age range from 8 to 66 years.
The mean age of the studied patients was 35.7 years with female predominance 63.6 %.
All the patients were asymptomatic. Most of them gave a history of close contact to COVID positive patients (70.45 % of cases), recent travel history (20.45 % of cases), while 2 patients came for preoperative assessment (4.45%) and 2 came for an annual checkup (4.45%).
MSCT chest showed abnormalities in all patients.
In our study, we noted that ground-glass opacity was the predominant radiological finding (41, 93%) which agrees with the study done by Heng et al. who noted that ground glass was the most evident radiological finding in COVID-19 positive asymptomatic patients [14] (Fig. 1).
We have noticed simple GGO in 28 cases (63.6%), GGO with interlobular septal thickening in 8 cases (18.8 %), GGO with halo sign in 4 cases (9%), and GGO with subpleural curvilinear line in 1 case (2.27%), compared with the results of Heng et al., who found that simple GGO in 51.7%, GGO with fine reticulation in 12.1%, GGO with halo sign in 8.6%, and GGO with subpleural curvilinear line in 10.3% [14] (Fig. 2).
Consolidation was seen in 3 patients (6.81 %) of cases, which agrees to the results of Heng’s study who found consolidation in 5.2% of patients (Fig. 3).
The ground-glass and consolidative opacities were peripheral in most patients (34, 77.3%), while 3 patients(6.81%) showed peri-hilar distribution and 7 patients (15.9%) showed peripheral with perihilar involvement which is highly matching results of the study” CT imaging and clinical course of asymptomatic cases with COVID-19 pneumonia” done by Ming et al. which found that the lesions mostly located in peripheral (44, 75.9%), and 14 (24.1%) patients presented central distribution [14].
Less than half of the patients (20, 45.5%) presented bilateral lesions; 24 (54.5%) patients showed unilateral lung distribution. That was not matching with Heng’s study who found that unilateral involvement was more common (59%). While our results matching a study done by Allan who found that abnormalities were bilateral in 86% of cases, mostly evident in the lower lobes and peripheral lung zones [14, 15] (Fig. 4).
The left lower lobe showed the highest predominance (32, 72.7%), followed by the right lower lobe (22, 50%) and equal incidence in both upper lobes (31.8 %), which is matching result of Allen’s and Heng’s study who showed lower lobe predilection of the disease [14, 15] (Fig. 5).
Reversed halo sign, pleural effusions, pericardial effusion, cavitation, mediastinal, and hilar lymph node enlargement were not seen in any of our patients