In patients recovering from COVID-19 infection, four stages of evolution on chest CT were identified: early stage (0-4 days); progressive stage (5-8 days); peak stage (10-13 days); and absorption stage (≥14 days). Key Results1. In patients who recovered from COVID-19 pneumonia, initial lung findings on chest CT were small subpleural ground glass opacities (GGO) that grew larger with crazy-paving pattern and consolidation.2. Lung involvement increased to consolidation up to two weeks after disease onset.3. After two weeks, the lesions were gradually absorbed leaving extensive GGO and subpleural parenchymal bands.This copy is for personal use only. To order printed copies, contact reprints@rsna.org I n P r e s s Abstract:Background: Chest CT is used to assess the severity of lung involvement in COVID-19 pneumonia. Purpose:To determine the change in chest CT findings associated with COVID-19 pneumonia from initial diagnosis until patient recovery. Materials and Methods:This retrospective review included patients with RT-PCR confirmed COVID-19 infection presenting between 12 January 2020 to 6 February 2020. Patients with severe respiratory distress and/ or oxygen requirement at any time during the disease course were excluded.Repeat Chest CT was obtained at approximately 4 day intervals. The total CT score was the sum of lung involvement (5 lobes, score 1-5 for each lobe, range, 0 none, 25 maximum) was determined.Results: Twenty one patients (6 males and 15 females, age 25-63 years) with confirmed COVID-19 pneumonia were evaluated. These patients underwent a total of 82 pulmonary CT scans with a mean interval of 4±1 days (range: 1-8 days). All patients were discharged after a mean hospitalized period of 17±4 days (range: 11-26 days). Maximum lung involved peaked at approximately 10 days (with the calculated total CT score of 6) from the onset of initial symptoms (R2=0.25), p<0.001). Based on quartiles of patients from day 0 to day 26 involvement, 4 stages of lung CT were defined: Stage 1 (0-4 days): ground glass opacities (GGO) in 18/24 (75%) patients with the total CT score of 2±2; (2) Stage-2 (5-8d days): increased crazy-paving pattern 9/17 patients (53%) with a increase in total CT score (6±4, p=0.002); (3) Stage-3 (9-13days): consolidation 19/21 (91%) patients with the peak of total CT score (7±4) ; (4) Stage-4 (≥14 days): gradual resolution of consolidation 15/20 (75%) patients with a decreased total CT score (6±4) without crazy-paving pattern. Conclusion:In patients recovering from COVID-19 pneumonia (without severe respiratory distress during the disease course), lung abnormalities on chest CT showed greatest severity approximately 10 days after initial onset of symptoms.

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The precise modification of redoxs pecies on the inner and outer surfaces of hollownanostructures is relevant in catalysis,surface science,and nanotechnology,but has proven difficult to achieve.H erein, we develop af acile approach to specifically fabricate Pt and Co 3 O 4 nanoparticles (NPs) onto the interior and exterior surface of hollowc arbon nitride spheres (HCNS), respectively,t op romote the surface redox functions of the polymer semiconductors.T he photocatalytic water splitting activities of HCNS with spatially separated oxidation and reduction centers at their nanodomains were enhanced. The origin of the enhanced activity was attributed to the spatially separated reactive sites for the evolution of H 2 and O 2 and also to the unidirectional migration of the electron and hole on the Janus surfaces,t hereby preventing the unwanted reverse reaction of water splitting and decreasing charge recombination.

Acknowledgements: None. months of uninterrupted radiation oncology clinical operation through the worst of the Wuhan outbreak, no known COVID-19 infection occurred at our radiotherapy center to our patients or employees. This report may provide valuable information for other radiation oncology departments during this unprecedented public health crisis.