Review
Copyright ©The Author(s) 2021.
World J Radiol. Jun 28, 2021; 13(6): 171-191
Published online Jun 28, 2021. doi: 10.4329/wjr.v13.i6.171
Table 1 Three main chest radiographic scoring systems use for coronavirus disease-2019 and their characteristic features

Chest Radiography Scoring Systems for COVID-19
Characteristics of Chest Radiography Scoring SystemsSevere Acute Respiratory Infection[48]Radiographic Assessment of Lung Edema[49]Chest X-ray Score[51]
Division of LungsNone2 lungs6 zones (3 zones each lung)
Methodology of Score CalculationEntire lungs scored as oneEach lung scored and totaledEach zone scored and totaled
Characteristics ScoredVarious radiographic findings1GGOs or consolidationVarious radiographic findings
Scoring Scale1 = normal; 2 = patchy/hyperinflation/bronchial wall thickening; 3 = focal consolidation; 4 = multifocal consolidation; 5 = diffuse alveolar change1 ≤ 25%; 2 = 25%-50%; 3 = 50%-75%; 4 ≥ 75%0 = no abnormalities; 1 = interstitial infiltrates; 2 = interstitial (predominant) & alveolar infiltrates; 3 = interstitial & alveolar (predominant) infiltrates
Designed Specifically for COVID-19 DiseaseNoNoYes
Table 2 Three main chest computed tomography scoring systems use for coronavirus disease-2019 and their characteristic features

Chest CT Scoring Systems for COVID-19
Characteristics of Chest CT Scoring SystemsChest Computed Tomography Severity Score[52]Total Severity Score [53]Chest Computed Tomography Score [54]
Division of Lungs20 regions for each lung5 lobes5 lobes
Methodology of Score CalculationEach region scored & amount totaledEach lobe scored and amount totaledEach lobe scored and amount totaled
Characteristics ScoredAmount of opacification% of disease in each lobe (1GGOs, mixed GGOs, consolidation)% of disease in each lobe (no specific features)
Scoring Scale0 = 0%; 1 = 1%-50%; 2 = 51%-100%0 = 0%; 1 = 1%-25%; 2 = 26%-50%; 3 = 51%-75%; 4 = 76%-100%0 = 0%; 1 ≤ 5%; 2 = 5%-25%; 3 = 26%-49%; 4 = 50%-75%; 5 ≥ 75%
Sensitivity & Specificity83% & 94%83% & 100%80% & 82%
Lowest Score for Severe COVID-19 Cases19.57.57
Designed Specifically for COVID-19 DiseaseYesYesYes
Table 3 Four most common imaging modalities used in the diagnosis and management of coronavirus disease-2019 and their unique features/findings characterized by organ system

Characteristic Features of COVID-19 by Imaging Modality
Organ Systems Impacted by COVID-191CTUltrasoundMagnetic resonance imagingChest radiography
Pulmonary2GGOs and reticular opacities; consolidations; 3crazy paving pattern; multifocal and bilateral in a peripheral, sub-pleural, and posterior distribution4B-line artifacts; irregularly thickened pleura; sub-pleural consolidationsSimilar to CTInterstitial reticular and reticulonodular patterns; alveolar hazy pulmonary opacities (equivalent to GGOs on CT); consolidations; multifocal & bilateral in a peripheral, sub-pleural, and posterior distribution
CardiacCardiac thromboembolismPericardial effusionMyocarditis; pericardial effusion
NeurologicalStroke (ischemic/thromboembolic)Venous sinus thrombosisStroke (ischemic/thromboembolic); venous sinus thrombosis, hyper-intensities
GastrointestinalWall thickening; edema; fluid filled intestinal lumen; mucosal hyper-enhancement; mesenteric vascular thrombi/ischemiaPortal vein thrombosis
GenitourinaryPerinephric fat strandingRenal vein/artery thrombosis
Table 4 Two main standardized reporting systems used for coronavirus disease-2019 compared by their characteristic features

Standardized CT Imaging Reporting Systems for COVID-19
Characteristics of the Reporting SystemCoronavirus Disease 2019 Reporting and Data System[118]-Dutch Radiological SocietyConsensus Statement on Reporting Chest CT Findings for COVID-19-Radiological Society of North America[120]
Type of Reporting SystemQuantitativeQualitative
Components & Relationship Between Both Reporting Systems 0 = inadequate or suboptimal imagingNo equivalent
1 = very low suspicion for COVID-19 with findings of non-infectious etiologyNegative for pneumonia = no CT features to suggest pneumonia
2 = low suspicion of COVID-19 with infectious findings not typical for COVID-19Atypical appearance = absence of typical or indeterminate features & the presence of lobar or segmental consolidation, but no GGOs or centrilobular nodules
3 = equivocal scan with common findings of COVID-19No equivalent
4 = high suspicion of COVID-19 with typical features that overlap with other viral pneumoniasIndeterminate appearance = absence of typical features and the presence of multifocal, diffuse, or unilateral GGOs with or without consolidation in a non-specific distribution
5 = very high suspicion of COVID-19 with typical findings of disease in typical locationsTypical appearance = peripheral and bilateral GGOs with or without consolidations/crazy paving pattern
6 = RT-PCR positive COVID-19No equivalent
Inter-observer agreementAbsolute agreement between 68.2% of observers; > 80% observer agreement on COVID-19 being low to very low or high to very highNo data