Abstract :
To grade and evaluate the percentage of pulmonary parenchymal involvement of COVID-19 infection on high-resolution chest computed tomography (CT) and its relationship with clinical classification. A retrospective cross-sectional study was conducted from Sep. 15, 2020, to Dec. 15, 2020, on 100 patients with a definite diagnosis of COVID-19 infection who had at least one chest CT scan in the course of their illness. The percentage of total parenchymal involvement of non-aerated lung tissue and the nature of acute pulmonary inflammatory lesions in both lungs were evaluated; each segment was considered to constitute 5% of lung parenchyma. The areas of both lungs involvement were classified from 0–4 grading scale as follows: 0 (0%), 1 (≤5 –30%), 2 (31–50%), 3 (51–75%), or 4 (76–100%).The pattern of involvement regarding GGO and consolidations was further categorized into A, B and C according to predominating features or a combination of both. 100 patients have been included in this study, 56 males and 44 females. Three (3%)patients were of a mild type, 53(53%) patients were of the moderate type, 34(34%) patients were of a severe type, and 10(10%) patients were of extremely severe type. Radiologically, 3(3%) patients were grade 0, 22(22%) patients were grade 1, 38(38%)patients were grade 2, 27(27%)patients were grade 3 and 10(10%)patients were grade 4. Most patients with radiological grades 1 and 2 were of moderate severity illness, of (21[95.5%]) and (30[78.9%]) respectively, while most (24[88.9%]) of grade 3 were of the severe type, and most (8[80%]) of grade 4 were of extremely severe type. There was a significant statistical association between radiological grading and clinical classification of the disease (p<0.001), with sensitivity and specificity for illness severity was (95.79%) and (66.67%) respectively. Chest CTS semi-quantitative evaluation provides a rapid and adequate method for detection and grading the parenchymal damage and correlates with clinical classification.
