Crazy paving pattern demonstrates as thickened interlobular septa and intralobular lines with superimposition on a GGO background, resembling irregular paving stones (Fig. 2b), which was not frequently observed as GGO and consolidation [20, 26]. Based on the previous pathological knowledge of SARS, this sign may result from the alveolar edema and interstitial inflammatory of acute lung injury [15, 30]. Recent investigations reported 5~36% COVID-19 patients with crazy paving pattern in their studies [12, 23]. Additionally, in combination with diffuse GGO and consolidation, crazy paving pattern can be the signal of COVID-19 entering progressive or peak stage [20].