Diagnostic Value of Window Width and Slice Thickness in Ground Glass Opacity of COVID-19/ 窗宽和层厚在COVID-19磨玻璃征象中的诊断价值

Objective To explore and select the best setting scheme of window width and slice thickness which is suitable for observing the ground glass opacity and various signs of 2019 novel coronavirus (COVID-19) Methods The imaging data of 11 patients with COVID-19 were analyzed retrospectively;and 30 COVID-19 lesions with ground glass opacity, paving stone sign, vascular thickening and air bronchogram sign were selected for analysis and comparison The display degrees of ground glass opacity and the other signs under different window widths and slice thicknesses at the fixed window level were subjectively scored by two chest imaging doctors with more than 15 years of diagnostic experience for obtaining the image quality score Results The window widths with the highest percentage for the ground glass opacity with a score of 3, the paving stone sign with a score of 3, vascular thickening with a score of 3 and air bronchogram sign with a score of 3 were 1000 HU (76 7%), 1400 HU (80%), 1400 HU (83 3%) and 1000 HU (83 3%), respectively, and there were statistical differences between the above results and those in other groups (P<0 001) For the signs (ground glass opacity, paving stone sign and vascular thickening and air bronchogram sign) with the highest score, the slice thickness with the highest proportion was 1 mm (100%), which was significantly different from other groups (P<0 001) Conclusion During the imaging diagnosis of COVID-19, the best window width for observing ground glass opacity and air bronchogram sign was 1000HU, and that for observing paving stone sign and vascular thickening is 1400 HU Moreover, 1mm is the best slice thickness for observing ground glass opacity and various signs