Representative of PFT trend in relation to clinical course and axial images of noncontrast CT scan of the chest for case 4. (A) PFT trend (FVC, forced expiratory volume in 1 second [FEV₁], and DLCO) during clinical course. (B) Axial CT image, showing basilar predominant ground-glass opacities with peripheral and peribronchovascular distribution, representing HCT-OP. (C) CT scan, showing worsened subpleural ground-glass opacities while immunosuppression was rapidly tapered during reactivation of CMV viremia. Escalation of prednisone was not pursued given clinical stability and ICU admission for CMV viremia and Klebsiella bacteremia. (D) CT image, showing similar subpleural ground-glass opacities, while FEV₁ continued to decline and patient experienced worsening dyspnea on exertion.