Pulmonary involvement with generalized scleroderma is ordinarily diagnosed during life only after the condition has become recognizable on the chest x-ray.1-5 Although alterations in the x-ray may not become apparent until rather marked pulmonary changes have occurred, clinically significant impairment of pulmonary function may follow changes in the chest wall and diffuse pulmonary fibrosis not easily detectable roentgenographically.
Pulmonary function studies previously reported in this disease, with and without chest x-ray changes,4,6-10 have pointed to this fact, but have represented chiefly the secondary effects of the basic involvement of the sclerodermal process which is the variable amount of fibrosis of the chest wall and lung. Further, there has been no consistently reproducible technique available for defining and following the degree of soft-tissue changes in evaluation of the course of pulmonary scleroderma and its response to therapy.
It was felt that the use of a method measuring directly the