What differentials to entertain?
The features are those of diffuse crazy paving pattern with subpleural sparing. Therefore, the radiologic differential diagnosis is broad and includes pneumonia (especially pneumocystis pneumonia, if immunocompromised patient), pulmonary alveolar proteinosis (usually in younger patients), alveolar hemorrhage, bronchoalveolar carcinoma (unlikely given the symmetrical and widespread pattern), lymphangitic carcinomatosis (unlikely if no history of malignancy), radiation- or drug-induced pneumonitis, hypersensitivity pneumonitis (exposure and further clinical information necessary), and left heart failure (unlikely on this case).
Widespread symmetrical groundglass opacities associated with inter and intralobular septal thickening give the crazy paving pattern. There is subpleural and equivocal costophrenic recess sparing. Airways are normal, no pleural effusion. The mediastinal structures are unremarkable, no lymphadenopathy.