Utility of arterial phase of dynamic CT for detection of intestinal ischemia associated with strangulation ileus

AIM:To clarify the usefulness of arterial phase scans in contrast computed tomography (CT) imaging of stran-gulation ileus in order to make an early diagnosis. METHODS:A comparative examination was carried out with respect to the CT value of the intestinal tract wall in each scanning phase, the CT value of the content in the intestinal tract, and the CT value of ascites fluid in the portal vein phase for a group in which ischemia was observed (Group Ⅰ) and a group in which ischemia was not observed (Group N) based on the pathological findings or intra-surgical findings. Moreover, a comparative examination was carried out in Group Ⅰ subjects for each scanning phase with respect to average differences in the CT values of the intestinal tract wall where ischemia was suspected and in the intestinal tract wall in non-ischemic areas. RESULTS:There were 15 subjects in Group Ⅰ and 30 subjects in Group N. The CT value of the intestinal tract wall was 41.8 ± 11.2 Hounsfield Unit (HU) in Group Ⅰ and 69.6 ± 18.4 HU in Group N in the arterial phase, with the CT value of the ischemic bowel wall being significantly lower in Group Ⅰ. In the portal vein phase, the CT value of the ischemic bowel wall was 60.6 ± 14.6 HU in Group Ⅰ and 80.7 ± 17.7 HU in Group N, with the CT value of the ischemic bowel wall being significantly lower in Group Ⅰ; however, no significant differences were observed in the equilibrium phase. The CT value of the solution in the intestine was 18.6 ± 9.5 HU in Group Ⅰ and 10.4 ± 5.1 HU in Group N, being signifi-cantly higher in Group Ⅰ. No significant differences were observed in the CT value of the accumulation of ascites fluid. The average difference in the CT values between the ischemic bowel wall and the non-ischemic bowel wall for each subject in Group Ⅰ was 33.7 ± 20.1 HU in the arterial phase, being significantly larger compared to the other two phases. CONCLUSION:This is a retrospective study using a small number of subjects; however, it suggests that there is a possibility that CT scanning in the arterial phase is useful for the early diagnosis of strangulation ileus.