How do registration parameters affect quantitation of lung kinematics?
Assessing the quality of motion estimation in the lung remains challenging. We approach the problem by imaging isolated porcine lungs within an artificial thorax with four-dimensional computed tomography (4DCT). Respiratory kinematics are estimated via pairwise non-rigid registration using different metrics and image resolutions. Landmarks are manually identified on the images and used to assess accuracy by comparing known displacements to the registration-derived displacements. We find that motion quantitation becomes less precise as the inflation interval between images increases. In addition, its sensitivity to image resolution varies anatomically. Mutual information and cross-correlation perform similarly, while mean squares is significantly poorer. However, none of the metrics compensate for the difficulty of registering over a large inflation interval. We intend to use the results of these experiments to more effectively and efficiently quantify pulmonary kinematics in future, and to explore additional parameter combinations.
Cook
Tessa Sundaram
TS
Dept. of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
Tustison
Nicholas
N
Biederer
Jürgen
J
Tetzlaff
Ralf
R
Gee
James
J
D000465:Algorithms; D000818:Animals; D001696:Biomechanical Phenomena / Q000379:methods*; D003198:Computer Simulation; D021621:Imaging, Three-Dimensional / Q000379:methods*; D066298:In Vitro Techniques; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology*; D008954:Models, Biological; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013382:Subtraction Technique; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000379:methods