Comparison of pulmonary function test and computed tomography volumetry in living lung donors

We previously proposed calculating forced vital capacity (FVC) by the number of segments for size matching in living-donor lobar lung transplantation (LDLLT). The primary purpose of this study was to compare spirometry-obtained calculations of lower lobe volumes with three-dimensional (3D) computed tomography (CT) volumetric images. Our second goal was to compare the data of pulmonary function tests with CT volumetry in living lung donors.

Pulmonary function test, including FVC and total lung capacity (TLC), and 3D CT volumetry were performed pre-operatively in 21 healthy donor candidates for LDLLT. The relationship of 3D CT volumetric data and calculated volume of lower lobes by the number of segments was investigated. Also studied were 3D CT volumetric data in relation to FVC and TLC. Various pre-operative variables were analyzed retrospectively.

According to 3D CT volumetry, the right and left lower lobe volume was 26.3% ± 2.9% and 22.6% ± 3.1% of the total lung volume, respectively. We found a significant, strong correlation between each lower lobe volume and the total lung volume. Because the calculated volumes of right and left lower lobes by the number of segments were 26.3% and 21.1%, respectively, our results implied that the volume of both lower lobes was accurately described by the number of segments. FVC was significantly associated with TLC and the total lung volume.

We confirmed that it would be justified to estimate graft FVC by the number of segments according to the CT volumetric data in LDLLT.