Statistical correlation of CT ventilation imaging and V/Q spect in patients with lung cancer

Abstract

Radiation treatment of patients with lung cancer can benefit from knowledge of regional lung function. 4-D CT provides structural and anatomical information during tidal breathing which maybe used to measure mechanical properties related to deformation of the lung tissue including Jacobian and strain of deformation at high resolutions and as a function of time. Single photon emission computed tomography (SPECT) lung imaging also provides functional information using radioactive tracers with SPECT ventilation and SPECT perfusion imaging. Due to availability and ease of use, we performed B-spline deformable registration — this yielded 3D deformation fields between successive respiratory phases of the 4D CT data from which measures of regional lung function in 11 lung cancer patients were derived. Furthermore, we registered the max-inhale CT volume to both V SPECT and Q SPECT data sets using the Demon's non-rigid registration algorithm in all subjects. Subsequently, statistical correlation between CT ventilation images, Jacobian and strain values, with both V SPECT and Q SPECT was undertaken. Through statistical analysis with the Spearman's rank correlation coefficient (ρ), we found that Jacobian values have the highest correlation with both V SPECT and Q SPECT . Among strain values, λ 3 showed higher correlation with SPECT than the other measures.