Evolution of CT Findings and Lung Residue in Patients with COVID-19 Pneumonia: Quantitative Analysis of the Disease with a Computer Automatic Tool.

Roberto Grassi,Diletta Cozzi,Fabrizio Urraro,Roberta Galdiero,Umberto Atripaldi,Alfonso Reginelli,Salvatore Cappabianca,Roberta Grassi,Michele Coppola,Maria Paola Belfiore,Ornella Picascia,Carmine Picone,Vittorio Miele,Simona Magliocchetti,Vincenza Granata,Roberta Fusco,Giuliana Giacobbe,Elio Bignardi

doi:10.3390/jpm11070641

Abstract

Purpose: the purpose of this study was to assess the evolution of computed tomography (CT) findings and lung residue in patients with COVID-19 pneumonia, via quantified evaluation of the disease, using a computer aided tool. Materials and methods: we retrospectively evaluated 341 CT examinations of 140 patients (68 years of median age) infected with COVID-19 (confirmed by real-time reverse transcriptase polymerase chain reaction (RT-PCR)), who were hospitalized, and who received clinical and CT examinations. All CTs were evaluated by two expert radiologists, in consensus, at the same reading session, using a computer-aided tool for quantification of the pulmonary disease. The parameters obtained using the computer tool included the healthy residual parenchyma, ground glass opacity, consolidation, and total lung volume. Results: statistically significant differences (p value ≤ 0.05) were found among quantified volumes of healthy residual parenchyma, ground glass opacity (GGO), consolidation, and total lung volume, considering different clinical conditions (stable, improved, and worsened). Statistically significant differences were found among quantified volumes for healthy residual parenchyma, GGO, and consolidation (p value ≤ 0.05) between dead patients and discharged patients. CT was not performed on cadavers; the death was an outcome, which was retrospectively included to differentiate findings of patients who survived vs. patients who died during hospitalization. Among discharged patients, complete disease resolutions on CT scans were observed in 62/129 patients with lung disease involvement ≤5%; lung disease involvement from 5% to 15% was found in 40/129 patients, while 27/129 patients had lung disease involvement between 16 and 30%. Moreover, 8–21 days (after hospital admission) was an “advanced period” with the most severe lung disease involvement. After the extent of involvement started to decrease—particularly after 21 days—the absorption was more obvious. Conclusions: a complete disease resolution on chest CT scans was observed in 48.1% of discharged patients using a computer-aided tool to quantify the GGO and consolidation volumes; after 16 days of hospital admission, the abnormalities identified by chest CT began to improve; in particular, the absorption was more obvious after 21 days.

Highlights

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already assumed pandemic proportions, affecting over 100 countries in few weeks [1,2].Currently, the “gold standard” for diagnosis of COVID-19 infection is a real-time reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the viral DNA
Recent studies have demonstrated that computed tomography (CT) findings of COVID-19 pneumonia show ground glass opacity (GGO) with surrounding consolidation, with bilateral involvement, peripheral distribution, and multi-lobar distribution [3,4,5,6,7]
We investigate the use of a computer-aided tool in order to quantify the abnormalities visible on chest CT images in patients with COVID-19 pneumonia

Summary

Introduction

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already assumed pandemic proportions, affecting over 100 countries in few weeks [1,2].Currently, the “gold standard” for diagnosis of COVID-19 infection is a real-time reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the viral DNA. Recent studies have demonstrated that CT findings of COVID-19 pneumonia show ground glass opacity (GGO) with surrounding consolidation, with bilateral involvement, peripheral distribution, and multi-lobar distribution [3,4,5,6,7]. The consolidation, or GGO with consolidation, increased, and reticular was observed in the later stages (scan > 1 week after symptom onset), this represents the conversion of findings from GGO to consolidation, and an increase in the reticulation pattern in affected lung parenchyma. CT features had rapid sever changes, from focal unilateral pulmonary parenchyma to diffuse bilateral GGO, or GGO with consolidation, within 1–3 weeks [6,7]. Several studies have described the CT imaging features of COVID-19 pneumonia, so far, there is a lack of large-sample CT imaging studies and follow-up observations [8,9,10,11,12,13,14,15,16,17,18,19,20]

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