الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
T
he results of this study confirmed that chest HRCT is important as a triage tool in categorizing suspicious cases with COVID-19 by using index test readers, CO-RADs, and RSNA scoring systems, especially in areas with high disease prevalence. This gave an overall good diagnostic performance among adult patients while it should be correlated with clinical and laboratory results in pediatric patients.
Pediatric patients with COVID-19 have relatively milder clinical symptoms, a higher prevalence of negative CTs, and decreased disease extension on imaging than adults.
Analyzing the positive chest HRCT data showed the typical lung involvement pattern in adults and pediatrics was mainly multi-lobar, bilateral, rounded-shaped, and peripheral opacities. In adults, the GGOs were the most common lung opacity, followed by crazy paving, then consolidations, then subpleural bands. While in the pediatrics, consolidations were the most encountered type of lung opacity, followed by GGOs, then peri-bronchial thickening, which was also uncommonly seen in adults, followed by crazy paving. At the same time, the peripheral and multi-lobar distributions were significantly higher in adults. Both adults and pediatrics typically showed vascular dilatation sign. Both adults and pediatrics rarely showed reverse halo sign, halo sign, mediastinal lymph nodes, tree in bud appearance, pleural effusion, pulmonary fibrosis, and pulmonary nodules.
The application of the semi-quantitative scoring method on baseline chest HRCT was used to assess the severity and the extent of COVID-19 pneumonia by calculating the sum of individual lobar affection scores. The total CT severity score in adult cases is significantly higher than that in pediatrics.
CO-RADs and the RSNA chest CT classification systems are comparable to one another in the diagnosis of COVID-19 pneumonia with similar sensitivity and reliability values. The current study concluded that the higher the diagnostic thresholds, i.e., CO-RADs 4 / the typical RSNA category applied, the more increase in the specificity at the cost of sensitivity.
The overall CO-RADs and RSNA scoring systems showed highly significant results when comparing the total suspected adult and pediatric cases, the positive and negative adult cases, and the proven positive adult and pediatric cases, while there was no significant result when comparing the positive and negative pediatric cases.
The most encountered CO-RADs and RSNA categories among the positive pediatric patients were CO-RADs 1 & 2 and the negative & atypical RSNA categories, while CO-RADs 4 & 5 and the typical RSNA categories were the most encountered among the positive adult patients.
CO-RADs 1 and 2 and RSNA classification categories of negative and atypical do not exclude COVID-19 infection, especially in pediatrics, so combining the results with exposure history, clinical symptoms, and laboratory findings, as well as RT-PCR results, should be considered in highly suspected cases. Also, recommendations to implement a new scoring system for this age group.