HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) VIDEOS Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Google Scholar Articles by Seo, H. Articles by Kim, Y. H. PubMed PubMed Citation Articles by Seo, H. Articles by Kim, Y. H. Social Bookmarking                      What's this? Hotlight (NEW!) What's Hotlight?

Diagnosis of Acute Appendicitis With Sliding Slab Ray-Sum Interpretation of Low-Dose Unenhanced CT and Standard-Dose IV Contrast-Enhanced CT Scans

¹ Department of Radiology, Seoul National University College of Medicine, Seoul National University Bundang Hospital 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea.
² Department of Radiology, Seoul Medical Center, Seoul, Korea.
³ Department of Emergency Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Korea.
⁴ Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Korea.

OBJECTIVE. The purpose of this study was to compare low-dose unenhanced CT with standard-dose IV contrast-enhanced CT in the diagnosis of appendicitis.

MATERIALS AND METHODS. Two hundred seven adults with suspected appendicitis underwent CT with mean effective doses of both 4.2 and 8.0 mSv. Two radiologists retrospectively reviewed thin-section images by sliding a 5-mm-thick ray-sum slab. They rated the likelihood of appendicitis and appendiceal visualization on 5- and 3-point scales, respectively, and proposed alternative diagnoses. Likelihood 3 was considered a positive diagnosis. Receiver operating characteristics analysis, the McNemar test, and the Wilcoxon's signed-rank test were used.

RESULTS. Seventy-eight patients had appendicitis. The values of the area under the receiver operating characteristics curve were 0.98 for the low-dose unenhanced acquisition and 0.97 for the standard-dose contrast-enhanced acquisition for reader 1 (95% CI for the difference, -0.02 to 0.03) and 0.99 and 0.98 (-0.02 to 0.02) for reader 2. Sensitivity was 98.7% for low-dose unenhanced CT and 100% for standard-dose contrast-enhanced CT for reader 1 (p = 1.00) and 100% for both techniques for reader 2. Specificity was 95.3% and 93.0% (p = 0.25) and 96.9% and 96.9%. The interpretation was indeterminate (score 3) in 0.5% and 1.4% of cases for reader 1 (p = 0.63) and 0.5% and 0% for reader 2 (p = 1.00). A normal appendix was not visualized in 5.4% and 3.9% of cases by reader 1 (p = 0.63) and 3.9% and 2.3% of cases by reader 2 (p = 0.50). None of the patients whose appendix was not visualized had appendicitis. Diagnostic confidence, visualization score for a normal appendix, and correct alternative diagnosis tended to be compromised with use of low-dose unenhanced CT, showing a significant difference for a reader's confidence in the diagnosis of appendicitis (p = 0.004). The two techniques were comparable in the diagnosis of appendiceal perforation.

CONCLUSION. Low-dose unenhanced CT is potentially useful in the diagnosis of appendicitis.

Keywords: appendicitis • contrast material • CT • radiation dosage

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				E. K. Paulson and C. A. Coursey CT Protocols for Acute Appendicitis: Time for Change Am. J. Roentgenol., November 1, 2009; 193(5): 1268 - 1271. [Full Text] [PDF]