Min Yeong Kim MD, Presenter: Nothing to Disclose

Woo Kyoung Jeong MD, Abstract Co-Author: Nothing to Disclose

Yong-Soo Kim MD, PhD, Abstract Co-Author: Nothing to Disclose

Jinoo Kim, Abstract Co-Author: Nothing to Disclose

Soo-Yeon Kim MD, Abstract Co-Author: Nothing to Disclose

Soon-Young Song, Abstract Co-Author: Nothing to Disclose

Seung Woo Cha MD, Abstract Co-Author: Nothing to Disclose

To evaluate the limitations of established CT criteria for acute appendicitis and to propose a feasible CT criterion, diameter with compression (DWC) for the appendix with borderline diameter.

We retrospectively reviewed consequetive medical records of 460 adult patients who underwent CT for suspected appendicitis and total 216 patients with visible appendices were enrolled after pathologic or clinical confirmation. CT criteria were as follows, maximal outer diameter (MOD), mural thickness and enhancement, intraluminal content, periappendiceal infiltration, appendicolith and DWC which is expected diameter after deduction of intraluminal compressive contents such as air or feces. Chi-square test and receiver operating characteristic (ROC) curves were used for statistical analyses.

MOD was ranged from 5.7mm to 26.3mm in 80 appendicitis patients and from 3.1mm to 9.8mm in 136 non-appendicitis patients. The area under the ROC curve (AUC) of MOD, DWC and mural thickness was 0.967, 0.973 and 0.670. The optimal cutoff value was greater than 8.2mm of MOD and greater than 6.4mm of DWC. MOD between 5.7mm and 9.8mm was the overlapping range in which 87 patients (45.6%) were included. In the overlapping range, AUC of MOD sharply declined to 0.767 but AUC of DWC remained 0.923. Use of a criterion of DWC yielded a higher sensitivity and accuracy than MOD.

Appendices with borderline diameter on CT are still difficult to interpret by established criteria due to enlargement by normal air-filling or periappendiceal inflammation. However DWC is a consistent CT criterion to evaluate appendicitis regardless of MOD.

DWC is affected not by normal distension or periappendiceal inflammation but by true appendicitis. Therefore DWC is a consistent CT criterion to evaluate appendicitis regardless of MOD.

Kim, M, Jeong, W, Kim, Y, Kim, J, Kim, S, Song, S, Cha, S, How to Evaluate the Appendix with Borderline Diameter on CT: Reconsideration of the Established CT Criteria and Proposal of a Solution Derived from Ultrasonography.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11013809.html