A comparative study to validate the use of ultrasonography and computed tomography in patients with post-operative intra-abdominal sepsis.
OBJECTIVE
To validate abdominal ultrasonography and helical computed tomography in detecting causes for sepsis in patients after abdominal surgery and to determine improved criteria for its use.


METHODS
Eighty-five consecutive surgical patients primarily operated for non-infectious disease were included in this prospective study. Forty-one patients were admitted to the intensive care unit. All patients were suspected of an intra-abdominal sepsis after abdominal surgery. Both ultrasonography (US) and helical abdominal computed tomography (CT) were performed to investigate the origin of an intra-abdominal sepsis. The images of both US and CT were interpreted on a four-point scale by different radiologists or residents in radiology, the investigators were blinded of each other's test. Interpretations of US and CT were compared with a reference standard which was defined by the result of diagnostic aspiration of suspected fluid collections, (re)laparotomy, clinical course or the opinion of an independent panel. Likelihood ratios and post-test probabilities were calculated and interobserver agreement was determined using kappa statistics.


RESULTS
The overall prevalence of an abdominal infection was 0.49. The likelihood ratio (LR) of a positive test-result for US was 1.33 (95% CI: 0.8-2.5) and for CT scan 2.53 (95% CI: 1.4-5.0); corresponding post-test probabilities for US 0.57 (95% CI: 0.42-0.70) and for CT 0.71 (95% CI: 0.57-0.83). The LR of a negative test-result was, respectively, 0.60 (95% CI: 0.3-1.3) and 0.18 (95% CI: 0.06-0.5); corresponding post-test probabilities for US 0.37 (95% CI: 0.20-0.57) and for CT 0.15 (95% CI: 0.06-0.32) were calculated.


CONCLUSIONS
Computed tomography can be used as the imaging modality of choice in patients suspected of intra-abdominal sepsis after abdominal surgery. Because of the low discriminatory power ultrasonography should not be performed as initial diagnostic test.
Go
H L S
HL
Department of Radiology, Academic Medical Center, University of Amsterdam, C-1, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands.
Baarslag
H J
HJ
Vermeulen
H
H
Laméris
J S
JS
Legemate
D A
DA
D000005:Abdomen / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011860:Radiography, Abdominal; D018805:Sepsis / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed; D014463:Ultrasonography