Predictive value of chest CT scoring in COVID-19 patients in Wuhan, China: A retrospective cohort study

Abstract

Background: Computed tomography (CT) findings of COVID-19 patients were demonstrated by cases series and descriptive studies, but quantitative analysis performed by clinical doctors and studies on its predictive value were rarely seen. The aim of the study is to analyze CT score in COVID-19 patients and explore its predictive value.

Materials and methods: We conducted a retrospective cohort study among confirmed COVID -19 patients with available CT images between February 8, 2020 and March 7, 2020. The lung was divided into six zones by the level of tracheal carina and the level of inferior pulmonary vein bilaterally on CT. Ground-glass opacity (GGO), consolidation, crazy-paving pattern and overall lung involvement were rated by Likert scale of 0-4 or binary as 0 or 1. Global severity score for each targeted pattern was calculated as total score of six zones.

Results: There were 53 patients and 137 CT scans included in the study. There were 18(34%) of the patients classified as moderate cases while 35(66%) patients were severe/critical cases. Severe/critical patients had higher CT scores in several types of abnormalities than moderate patients from the second week to the fourth week post symptom onset. Overall lung involvement score in the second week demonstrated predictive value for severity with a sensitivity of 81.0% and specificity of 69.2%.

Conclusions: Our modified semi-quantitative CT scoring system for COVID-19 patients demonstrated feasibility. Overall lung involvement score on the second week had predictive value for clinical severity and could be indicator for further treatment.

Keywords: COVID-19; Computed tomography; Pneumonia; Prognosis; Severity of illness.

Fig. 1

CT scoring system demonstration. A: CT images of a 40-year-old male patient who presented with fever, cough and mild hemoptysis and was identified as moderate case by clinical criteria. The axial non-contrast CT images showed unilateral focal pure ground glass opacity (GGO) with no crazy-paving pattern or consolidation. B: CT images of a 73-year-old male who presented with fever, cough, fatigue, and dyspnea and was defined as severe case by clinical criteria. The axial non-contrast CT images showed bilateral pure ground glass opacity (GGO) with no crazy-paving pattern or consolidation. The lesions were distributed in the peripheral and posterior part of the lung (severe case). Each of the three images of the same patient showed bilateral upper zone, median zone, and lower zone.

Fig. 2

CT images from patients of different disease severity. A: CT images of a 43-year-old male patient who presented with fever, shiver, cough and headache, and was identified as moderate case by clinical criteria. The axial non-contrast CT images showed multi-focal ground glass opacity (GGO) with curvilinear lines(arrow) but no consolidation. B: CT images of a 64-year-old male patient who presented with fever, shiver, cough, diarrhea and dyspnea, and was classified as sever case by clinical criteria. The axial non-contrast CT images showed bilateral peripheral distributed ground glass opacity with reticulation, presenting as crazy-paving pattern (arrows). C: CT images of a 73-year-old female patient who was transferred to our hospital with sever hypoxia who was later intubated and put on ECMO. The axial non-contrast CT images showed diffuse ground glass opacity (GGO) with bilateral posterior distributed crazy-paving pattern and consolidation (arrows).

Fig. 3

CT scores in COVID-19 patients of different severity based on time course. A: Overall lung involvement score B: Ground-glass opacity score C: Consolidation score D: Crazy-paving pattern score.

Fig. 4

Receiver operating characteristic curves and AUCs of the predictors for severity of disease.