Radiologic and Functional Analysis of Compensatory Lung Growth After Living-Donor Lobectomy

Background: Whether compensatory lung growth occurs in adult humans is controversial. The aim of this study was to confirm compensatory lung growth by analyzing ipsilateral residual lung after lower lobectomy in living lung transplant donors with quantitative and qualitative computed tomography assessments.

Methods: Chest computed tomography and pulmonary function tests were performed in 31 eligible donors before and 1 year after donor lobectomy. Ipsilateral residual lung volume was measured with three-dimensional computed tomography volumetry. The computed tomography-estimated volumes of low, middle, and high attenuations in the lung were calculated. Assessment of the D value, a coefficient of the cumulative size distribution of low-density area clusters, was performed to evaluate the structural quality of the residual lung.

Results: Postoperative pulmonary function test values were significantly larger than preoperative estimated values. Although postoperative total volume, low attenuation volume, middle attenuation volume, and high attenuation volume of the ipsilateral residual lung were significantly larger than the preoperative volumes, with 50.2%, 50.0%, 41.5%, and 43.1% increase in the median values, respectively (all p < 0.0001), the differences in D values before and after donor lobectomy were not significant (p = 0.848). The total volume of ipsilateral residual lung was increased by more than 600 mL (50%).

Conclusions: The volume of ipsilateral residual lung increased, but its structural quality did not change before and after donor lobectomy. The existence of compensatory lung growth in adult humans was suggested by quantitative and qualitative computed tomography assessments.