Evaluation of lobar biomechanics during respiration using image registration.

The human lungs are divided into five independent compartments called lobes. The lobar fissures separate the lung lobes. It is hypothesized that the lobar surfaces slide against each other during respiration. We propose a method to evaluate the sliding motion of the lobar surfaces during respiration using lobe-by-lobe mass-preserving non-rigid image registration. We measure lobar sliding by evaluating the relative displacement on both sides of the fissure. The results show a superior-inferior gradient in the magnitude of lobar sliding. We compare whole-lung-based registration accuracy to lobe-by-lobe registration accuracy using vessel bifurcation landmarks.