COVID-19 severity scoring systems in radiological imaging – a review

Abstract

The current reference standard to make a definitive diagnosis of SARS-CoV-2 infection is the reverse transcription- polymerase chain reaction assay (rt-PCR). However, radiological imaging plays a crucial role in evaluating the course of COVID-19 and in choosing proper management of infected patients. Chest X-ray (CXR) is generally considered not to be sensitive for the detection of pulmonary abnormalities in the early stage of the disease. However, in the emergency setting CXR can be a useful diagnostic tool for monitoring the rapid progression of lung involvement in COVID-19, especially in patients admitted to intensive care units. The rapid course of SARS-CoV-2 infection and the severity and progression of lung aberrations require a method of radiological evaluation to implement and manage the appropriate treatment for infected patients. Computed tomography (CT) imaging is considered to be the most effective method for the detection of lung abnormalities, especially in the early stage of the disease. Moreover, serial chest CT imaging with different time intervals is also effective in estimating the evolution of the disease from initial diagnosis to discharge from hospital. Despite having low specificity in distinguishing abnormalities in viral infections, the high sensitivity of CT makes this method ideal for assessing the severity of the disease in patients with confirmed COVID-19. In this review, we present and discuss currently available scales that can be used to assess the severity of lung involvement in COVID-19 patients in everyday work, both for CXR and CT imaging.

Trends over Time of Lung Function and Radiological Abnormalities in COVID-19 Pneumonia: A Prospective, Observational, Cohort Study

“…Chest CT images were assessed for the presence of peripheral and multifocal ground glass opacities, consolidations, fibrosis, and crazy-paving patterns. The severity of disease was evaluated using the Total Severity Score (TSS), as previously reported [ 26 , 27 ]. CT scanning protocols and scoring method is reported in the Supplementary Materials .…”

Quantification of COVID-19 Opacities on Chest CT – Evaluation of a Fully Automatic AI-approach to Noninvasively Differentiate Critical Versus Noncritical Patients

“…In face of the disadvantage of semi-automatic quantification methods, software-derived parameters might have the potential to predict severity of illness and clinical course and to enable early stratification of critical patients in a fully automatic manner. In addition, the automatic quantification enables an objective evaluation of the COVID-19 like changes independent from the experience of radiologists, which can play a major role in the assessment of the disease, especially for unexperienced observers [28] , [29] , [30] .…”

Effects of Prone Ventilation on Oxygenation, Inflammation, and Lung Infiltrates in COVID-19 Related Acute Respiratory Distress Syndrome: A Retrospective Cohort Study

“…While further investigation is needed to establish its ability to predict patient disposition after prone ventilation, we offer a method for quantitatively assessing lung infiltrate severity in CXRs captured near the time of intubation that may facilitate early proning in the management of CARDS patients. Our method resembles scoring systems reported in prior literature [ 28 , 29 ] but simplifies the procedure for scoring CXRs displaying confluent infiltrates; as a result of this adaptation, radiologists would not be required to distinguish between confluent infiltrates of interstitial or alveolar predominance. We believe this may lead to a more consistent interpretation of CXR findings, thereby increasing reproducibility and improving implementation of the score in a larger, multi-center study.…”

“…This scoring system resembles an experimental CXR score proposed by Borghesi and Maroldi [ 28 , 29 ]. Borghesi and Maroldi, however, proposed a scoring scale that ranges from 0 to 3 for each lung zone, with 2 assigned for confluent infiltrates with interstitial predominance and 3 assigned for confluent infiltrates with alveolar predominance.…”