Usefulness of 2D fusion of postmortem CT and antemortem chest radiography studies for human identification.

Purpose: To determine the feasibility of human identification through the two-dimensional (2D) fusion of postmortem computed tomography (PMCT) and antemortem chest radiography.

Materials And Methods: The study population consisted of 15 subjects who had undergone chest radiography studies more than 12 months before death. Fused images in which a chest radiograph was fused with a PMCT image were obtained for those subjects using a workstation, and the minimum distance gaps between corresponding anatomical landmarks (located at soft tissue and bone sites) in the images obtained with the two modalities were calculated. For each fused image, the mean of all these minimum distance gaps was recorded as the mean distance gap (MDG). For each subject, the MDG obtained for the same-subject fused image (i.e., where both of the images that were fused derived from that subject) was compared with the MDGs for different-subject fused images (i.e., where only one of the images that were fused derived from that subject; the other image derived from a different subject) in order to determine whether same-subject fused images can be reliably distinguished from different-subject fused images.

Results: The MDGs of the same-subject fused images were found to be significantly smaller than the MDGs of the different-subject fused images (p < 0.01). When bone landmarks were used, the same-subject fused image was found to be the fused image with the lowest MDG for 33.3% of the subjects, the fused image with the lowest or second-lowest MDG for 73.3% of the subjects, and the fused image with the lowest, second-lowest, or third-lowest MDG for 86.7% of the subjects. The application of bone landmarks rather than soft-tissue landmarks made it significantly more likely that, for each subject, the same-subject fused image would have the lowest MDG (or one of the lowest MDGs) of all the fused images compared (p < 0.05).

Conclusion: The 2D fusion of antemortem chest radiography and postmortem CT images may assist in human identification.