This cross-sectional multicenter study has been conducted on 220 Egyptian patients, 68 (30.9%) females and 152 (69.1 %) males, their age range was 10-92 years (average 49.198 years), from March to the end of May 2020. Non-contrast MSCT chest was done to all patients. Data assessment and analysis for lesions’ pattern, localization, and severity was done. Bilateral affection was seen in 168/220 cases (76.36%). Multilobar affection was noted in 186/220 cases (84.54%). Lower lobes affection was noted in 179/220 cases (81.36%). Peripheral/subpleural affection was noted in 203/220 cases (92.27%).The common (ground glass opacities, consolidation, crazy paving, vascular thickening, traction bronchiectasis, vacuolar sign, architectural distortion signs, and reversed halo sign) and the uncommon CT patterns (halo sign, masses, nodules, lobar affection, tree in-bud-pattern, and cysts) were discussed and associated extra-pulmonary lesions were described. Our results globally agree with the published literature [3,4,5,6,7,8,9, 11, 13, 14, 16,17,18].
In our study, we had only three pediatric patients; the CT findings were ground glass opacification in two cases and consolidation in one case. The lesions were similar to adult’s lesions in distribution. This complies with the findings described in literature .
A common pitfall that should be avoided in the diagnosis is mistaking osteophyte induced adjacent pulmonary fibrosis and atelectasis for subpleural COVID-19 lesions. The lesion is classically seen in the paravertebral region and is related to a vertebral osteophyte .
In the current situation where the numbers of cases of COVID-19 are in continuous ascent, we considered any CT pattern that reflects inflammation in a patient with clinical suspicion of COVID-19 as a case of COVID-19. Declaring that an inflammatory CT lesions is not COVID-19 because its pattern does not conform with the typical patterns of the disease is not logical in this time of peaking pandemic .Thus, applying the classification systems [6, 7, 10, 11] that actually depended on staging the probability of the disease (typical, atypical, or indeterminate) to any lesion in CT that suggests inflammation was not considered feasible by our team starting this May. According to our results, we regarded the lesions as either common to be seen with COVID-19 and thus stated as typical in the radiology report, or as uncommon lesions for COVID-19 (as nodules and masses , halo sign, lobar consolidation, or tree-in bud pattern) that if noted in a patient with clinical suspicion of the disease or a contact of a known case will be reported as an uncommon CT pattern of COVID-19, however, it reflects pulmonary infection thus COVID-19 should be considered.
Applying a severity score may be requested by clinicians. From our point of view, all the current severity scoring systems of COVID-19 [7, 20] have the following drawbacks:
➢ They are all based on visual assessment.
➢ They are totally subjective.
➢ They are time consuming.
➢ They are rather sophisticated.
➢ The clinician receiving the report needs to be acquainted with the scoring system you are using which is not very feasible if he is not in the same institute or in case of multicenter cases.
However, applying a scoring system may be needed for clinical purposes and in case of follow-up studies. We tried applying the severity score described in the radiology assistant  but with a trivial modification for example instead of stating that the score is 1 or is 24, we wrote it as 1/25 or 24/25, respectively, which will reflect a mild case in the first condition and a severe one in the second, we found that the results as such are self-explanatory and does not require prior acquaintance with the scoring system for interpretation.
In assessing the temporal changes of our cases, we had early lesions with only ground-glass opacities in 63cases (about 29%), and late cases with only architectural distortion and/or reversed halo sign in 38 cases (17.27%), with 119 cases (54.09%) showing signs of early, progressive, peak, and absorptive stages all together, thus we suggested a classification were stage 1 only have ground-glass opacities detected. This corresponds to the early initial stage in literature, stage 2 where the disease progresses may show ground-glass opacities with other lesions, crazy paving, or consolidation alone or associated with other lesions, and stage 3 showing signs of architectural distortion and/or reversed halo sign not associated with other lesions. This corresponds to the absorptive stage in literature .
In the early days of the COVID-19 crises, the role of CT chest in the management was debated both in China and later worldwide. Some authors have recommended it while other authors have restrained its use [16, 17]. The Fleischner Society has announced certain rules for the application of CT in cases of COVID-19 [6, 21], in April 2020, according to which CT could be done in cases of mild clinical features if patient is at risk for disease progression, also in patients with suspected COVID-19 who present with moderate-severe clinical features and a high pretest probability of disease, or there is worsening of the respiratory status. By the end of May 2020, in Egypt, those conditions are actually applicable and in the current pandemic peaking crisis according to our experience, CT is considered an essential cornerstone in the management of clinically suspected cases of COVID-19.