We propose a method for visualizing the amount of pleural sliding using 4DCT data to detect pleural
adhesions. To visualize the sliding motion between the visceral and the parietal pleurae through a half
breathing cycle, deformation field of the lungs and thoracic wall from an end-exhale phase (Te) to an endinhale
phase (Ti) was calculated using non-rigid image registration algorithm. All the phases between Te
and Ti were used to achieve accurate registration from Te to Ti, and overall deformation was obtained as
a composition of a series of small deformations. Based on the overall deformation field, the pleural sliding
motion is calculated by subtracting pairs of moving vectors on the surface of lungs and inner thoracic wall.
Three dimensional mapping was then created by plotting the norms of subtracted vectors on the surface of
the lungs. Two thoracic surgeons rated the correlation between areas with decreased sliding value and actual
locations of pleural adhesions in five-point scale with higher points given to stronger correlation. There were
good correlations between decreased sliding areas and pleural adhesions site (3.9 in average), suggesting
that our pleural sliding mapping has a potential to be a good predictor of the locations of pleural adhesions.