Diaphragm dimensions after single-lung transplantation for emphysema

We used three-dimensional reconstructions obtained with spiral computed tomography to measure total diaphragm surface area (A(di)), and the surface area of the dome (A(do)) and of the zone of apposition (A(ap)) of the diaphragm in nine patients with single-lung transplantation (SLT) for emphysema and nine normal subjects matched for age, sex, height, and weight. Measurements were obtained at supine FRC, midinspiratory capacity, and TLC. In the normal subjects, A(do) and A(di) were greater on the right than on the left side, and the right dome was positioned more cranially than the left one, presumably because of the presence of the liver. Compared with either the ipsilateral side in the controls or the native side in the patients, A(do) was smaller on the transplanted side because the mediastinum was shifted toward the graft. A(di) showed a similar trend. On the other hand, the radius of curvature of the dome in the coronal and sagittal planes was similar on the side of the graft and on the ipsilateral side in the controls. In conclusion, we found that after SLT for emphysema, diaphragm configuration comes back to normal but A(do), and with it A(di), remain smaller than in normal subjects because the mediastinum is displaced toward the graft.