Segmental analysis of respiratory liver motion in patients with and without a history of abdominal surgery.

ABSTRACT

PURPOSE: The purpose of this study was to analyze the respiratory motion of each segment of the liver in patients with or without a history of abdominal surgery using four-dimensional computed tomography. MATERIALS AND METHODS: In total, 57 patients treated for abdominal tumors using proton beam therapy were enrolled. Eighteen patients had a history of abdominal surgery and 39 did not. The positions of clearly demarcated, high-density regions in the liver were measured as evaluation points with which to quantify the motion of each liver segment according to the Couinaud classification. RESULTS: In total, 218 evaluation points were analyzed. Comparison of differences in the motion of individual liver segments showed that among patients without a history of surgery, the maximum was 29.0 (7.2-42.1) mm in S6 and the minimum was 15.1 (10.6-19.3) mm in S4. Among patients with a history of surgery, the maximum was 28.0 (9.0-37.4) mm in S7 and the minimum was 6.3 (4.1-9.3) mm in S3. CONCLUSION: The distances and directions of respiratory motion differed for each liver segment, and a history of abdominal surgery reduced the respiratory motion of the liver. It is necessary to selectively use the internal margin setting.