Abstract：Objective: To evaluate rectum cancer preoperative neoadjuvant therapy using hypotonic rectal air inflation MSCT. Methods: Imaging findings in 33 cases of pathologically confirmed colorectal cancer after neoadjuvant therapy were analyzed retrospectively. The assessment included: intestinal wall thickness at tumor site, the extent of tumor invlovement of intestinal circumference, the length of intestinal tumor, the features after enhancement, the peri-vascular fascia, lymph node enlargement, and T stage of tumor. Results: Hypotonic rectal air inflation MSCT pre- and post-neoadjuvant therapy can show the rectal lesion satisfactorily. Before therapy: the intestinal wall thickness at the tumor site was 4~10mm in 7 cases, 11~30mm in 15 cases, beyond 31mm in 11 cases. Involvement of the intestinal circumference: less than 1/3 in 6 cases, 1/3~1/2 in 11 cases, more than 1/2 less than whole circumference in 8 cases, whole circumferential involvement in 8 cases. The length of invlovement: less than 10mm in 4 cases, 10~30mm in 8 cases, 30~50mm in 14 cases, more than 50mm in 7 cases. All cases had moderate enhancement. Invasion of mucosal and submucosal layer in 7 cases, invasion of serosa in 15 cases, invasion beyond serosa in 11 cases. In 11 cases the peri-intestinal fatty tissue and fascia were invaded. Peri-intestinal, peritoneal and posterior peritoneal cavity lympy node enhargement were seen in 15 cases. Distant metastases in 4 cases. Occurrence of T1 stage was 15.15%, T2 stage was 30.30%, T3 stage was 42.42%, T4 stage was 12.12%. After therapy: the intestinal wall thickness became normal in 10 case, 4~10mm in 5 cases, 11~30mm in 10 cases, beyond 31mm in 8 cases, involvement of intestinal circumference less than 1/3 in 15 cases, more than 1/3 less than 1/2 in 12 cases, more than 1/2 less than whole circumference in 6 cases. Tumor length less than 10mm in 13 cases, 10~30mm in 6 cases, 30~50mmin 10 cases, beyond 50mm in 4 cases. All cases had mild enhancement. Invasion of mucosal and submucosal layer were seen in 10 cases, invasion of serosa layer in 17 cases, invasion beyond serosa in 6 cases. Peri-intestinal fatty tissue and fascia involvement in 2 cases. Peri-intestinal, peritoneal cavity and post-peritoneal cavity lymph node enlargement seen in 6 cases. Distant metastases were seen in 3 cases. After neoadjuvant therapy the changes of T stage were: T0 stage 30.30%, T1 stage 24.24%, T2 stage 30.30%, T3 stage 9.09%, T4 stage 6.06%. Conclusion: Hypotonic rectal air inflation MSCT is useful in evaluating the effect of neoadjuvant therapy and can accurately assessing the changes of T staging pre- and post-therapy.
2011, Vol. 22 
