SPIRAL COMPUTED TOMOGRAPHIC COLONOGRAPHY - DETERMINATION OF THE CENTRAL AXIS AND DIGITAL UNRAVELING OF THE COLON

Rationale and Objectives. The authors developed and tested automated a nd semiautomated bowel-lumen tracking and colon-unraveling techniques for determining the central axis of the bowel. Methods. A computer-sim ulated gastrointestinal tract phantom was used to test the accuracy of an automated algorithm for central axis determination and bowel unrav eling. Variations in cross-sectional features between straight and unr aveled 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. Results. Accuracy of the automated algorithm was confirmed by the high degree of correlatio n in the cross-sectional feature measurements (length error, <1%). For the canine colon segment, accuracy of the semiautomated algorithm was confirmed by comparison with the automated tracing. For the human col on, readings were reproducible with 3.5% (+/- 1.9 standard deviation) mean variation in length. Conclusion. An automated algorithm for centr al axis deterioration and unraveling the colon has been validated in a gastrointestinal tract phantom. A semiautomated algorithm has been sh own to be reproducible and time-efficient.