3D-CT lung volumetry using multidetector row computed tomography: pulmonary function of each anatomic lobe.

PURPOSE

We sought to determine the volume of each anatomic lung lobe reconstructed using 3-dimensional computed tomography (3D-CT) imaging from multidetector CT images and to compare these with pulmonary function test results.

MATERIALS AND METHODS

We reviewed preoperative 3D-CT images and spirometry results of 111 patients (86 men and 25 women) with pulmonary neoplasms who were considered candidates for lung resections. On a 3D-CT image, the entire lung was semiautomatically separated into 5 anatomic lobes: right upper lobe, right middle lobe, right lower lobe, left upper lobe, and left lower lobe. For each lobe, total lobar volume, emphysematous lobar volume with low attenuation values of less than -950 HU, and normal lobar volume (NLV=total lobar volume-emphysematous lobar volume) were calculated. Vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide (DLCO) were measured by spirometry. Relationships between NLV values of each lobe and pulmonary function results were determined by the Pearson correlation coefficients and multiple regression analysis.

RESULTS

The NLV values for both lower lobes (right lower lobe and left lower lobe) and the other lobes (right upper lobe, right middle lobe, and left upper lobe) were significantly correlated with vital capacity and forced expiratory volume in 1 second; lower lobes showed a stronger tendency toward these correlations. The NLV values of the lower lobes were significantly correlated with DLCO (P<0.001), although the NLV values of the other lobes were not correlated with DLCO (P=0.112).

CONCLUSIONS

Pulmonary function results, particularly DLCO, were primarily affected by the NLVs of the lower lobes.