CT in searching for abscess after abdominal or pelvic surgery in patients with neoplasia: do abdomen and pelvis both need to be scanned?

Purpose: This prospective study was undertaken to determine the incremental yield of combined abdominal and pelvic CT in searching for clinically suspected postoperative abscess in oncologic patients.

Method: One hundred seventeen oncologic patients underwent CT to exclude a clinically suspected abscess within 30 days of abdominal or pelvic surgery during an 8 month period. Scans were evaluated for the presence of ascites, loculated fluid collections, or other possible sources of fever. The clinical course and any intervention in the abdomen or pelvis within 30 days after CT were recorded.

Results: After abdominal surgery, 44 of 69 [64%; confidence interval (CI) 51-75%] patients had loculated fluid collections in the abdomen; no patient (0%; CI 0-5%) had a loculated fluid collection present only in the pelvis. After pelvic surgery, 22 of 48 (46%; CI 31-61%) patients had loculated fluid collections in the pelvis; no patient (0%; CI 0-7%) had a loculated collection present only in the abdomen. Loculated collections were present in both the abdomen and the pelvis in 4 of 69 (6%; CI 1.6-14%) patients after abdominal surgery and 3 of 48 (6%; CI 1.3-17%) after pelvic surgery.

Conclusion: Isolated pelvic abscesses after abdominal surgery and isolated abdominal abscesses after pelvic surgery appear to be very uncommon in oncologic patients. CT initially need be directed only to the region of surgery in this particular patient population.