Abdominal computed tomography for postoperative abscess: is it useful during the first week?

While classic teaching dictates computed tomography (CT) for postoperative abdominal or pelvic abscess in the first week is of low yield, little evidence supports intentional delays in imaging for suspected abscess. This retrospective review examined all CT scans obtained for clinical suspicion of abscess between 3 and 30 days after abdominal or pelvic operation over a 3-year period. Scans were grouped into those obtained between 3 and 7 days after surgery (EARLY) and those obtained after day 7 (LATE). Diagnostic yield was compared between EARLY and LATE groups. Of 262 CT examinations (EARLY, n = 106; LATE, n = 156), 71 studies (27%) demonstrated abscess. There was no significant difference in the diagnostic yield of CT for abscess between EARLY and LATE groups (23% [24 of 106] versus 30% [47 of 156], P = 0.18). Of patients with an abscess, 63% (45 of 71) underwent percutaneous or operative drainage (EARLY 75% [18 of 24], LATE 57% [27 of 47], P = 0.15). Abdominal CT for postoperative abscess can be expected to be diagnostic in a substantial proportion of cases in the first week, the majority of which lead to percutaneous or operative drainage. Postoperative CT for intra-abdominal abscess should be obtained as clinically indicated, regardless of interval from surgery.