Patterns of pulmonary perfusion scans in normal subjects. III. The prevalence of abnormal scans in nonsmokers 30 to 49 years of age.

The prevalence of abnormal pulmonary perfusion (Q) scans in persons without cardiopulmonary disease has not been well defined; this prevalence could impact on the current diagnostic approach to those in whom pulmonary embolic disease is suspected. In prior studies, we found that Q scan defects, particularly lobar or segmental defects, are rarely present in normal young smokers and nonsmokers. To determine if normal nonsmokers of an older age group have a higher prevalence of Q defects, we performed 6-view Q scans in 40 subjects 32 to 49 yr of age who had no known cardiopulmonary disease. Each subject had undergone a history, physical examination, electrocardiogram, spirometry, and posteroanterior chest roentgenogram prior to scanning. All Q scans were interpreted blindly and independently by 2 experienced readers. No subject demonstrated a lobar or segmental defect on 2 views. One subject with scoliosis had a subsegmental defect corresponding to a prominent aortic arch on the chest roentgenogram. We conclude that abnormal Q scans are extremely uncommon among normal nonsmokers 30 to 49 yr of age.