Figure 5b. CT scans from a 6-year longitudinal study in a 34-year-old persistent current smoker (30.0 pack-years at T0; 38.0 pack-years at T1). (a) Transverse thin-section CT scan targeted to the right lung at T0 shows faint parenchymal micronodules in the upper lung zones. (b) Transverse thin-section CT scan obtained at the same level as a at T1 shows replacement of the micronodular pattern by numerous small areas of hypoattenuation, indicative of emphysematous changes.