Figure 10. 70-year-old man with right upper lobe atelectasis associated with lung torsion due to squamous cell carcinoma. (a) Posteroanterior radiograph shows a mass-like opacity with sharp lateral margin overlying the right hilum. (b) Anterior location and sharp outer margin of the atelectatic lobe are demonstrated on the lateral radiograph. (c) Note that the atelectatic lobe migrates with change in the patient's position, as seen on CT scout view. (d) The atelectatic right upper lobe is located posteriorly on axial CT in the supine position. (Courtesy of Yasuyuki Kurihara, MD, St Marianna University, School of Medicine, Kawasaki-shi, Japan.)
