Spiral computed tomographic colonography: Determination of the central axis and digital unraveling of the colon

The authors developed and tested automated and semiautomated bowel-lumen tracking and colon-unraveling techniques for determining the central axis of the bowel. A computer-simulated gastrointestinal tract phantom was used to test the accuracy of an automated algorithm for central axis determination and bowel unraveling. Variations in cross-sectional features between straight and unraveled formats were compared in a canine bowel segment in vitro and a human colon in vivo by using spiral computed tomography. Three readers each performed three semiautomated evaluations. Accuracy of the automated algorithm was confirmed by the high degree of correlation in the crosssectional feature measurements (length error,