Abstract
Background: The aim of this retrospective study is to assess the accuracy of single slice helical
CT scan with intravenous, and rectal contrast (CTRC) in the diagnosis of acute appendicitis
(AA) in patients with suspected AA, with particular analysis of the diagnostic signs.
Participants and methods: Abdomino–pelvic helical CTRC was performed on 75 consecutive patients with suspicion
of AA. Radiologic diagnosis was compared with surgical/pathologic results and clinical
follow-up. In addition, the CTRC examinations were retrospectively reviewed independently
by two experienced radiologists using predefined diagnostic criteria. The sensitivity,
specificity, and frequency of each diagnostic sign were calculated. The interobserver
agreement and the statistical significance of the frequency for each diagnostic criterion
were assessed using the Kappa and Fisher tests, respectively. Results: The accuracy of helical CTRC in the diagnosis of AA was 94.7%, sensitivity 100%,
specificity 90%, PPV 89.7%, and the NPV 100%. Wall enhancement and nonopacification
of the appendix recorded the highest sensitivity and specificity (97% and 100%, 94%
and 95%, respectively). Appendiceal thickness greater than 6 mm was present in 100%
of true-positive cases. However, 26.5% of true-negative cases had also an appendiceal
diameter exceeding 6 mm, a value used as a cut-off for normal appendiceal diameter.
The highest interobserver agreement was recorded for appendiceal wall enhancement
and for nonopacification of the appendix (K=0.97 and 0.88, respectively). Conclusions: CTRC is an accurate and relatively fast technique for investigation of patients with
suspected AA. A negative CTRC can exclude completely the diagnosis of AA. Nonopacification
of the appendix and appendiceal wall enhancement are highly sensitive, specific, and
reproducible, signs representing major criteria for the diagnosis of AA.
Keywords
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Article info
Publication history
Published online: February 03, 2005
Accepted:
November 15,
2004
Received in revised form:
October 20,
2004
Received:
June 20,
2004
Identification
Copyright
© 2005 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
