Alexander Sauer MD, Presenter: Nothing to Disclose

Isabel Amelie Platzer MD, Abstract Co-Author: Nothing to Disclose

Jan-Stefan Schmid, Abstract Co-Author: Nothing to Disclose

Andreas Max Weng, Abstract Co-Author: Nothing to Disclose

Thorsten Alexander Bley MD, Abstract Co-Author: Nothing to Disclose

Werner Kenn MD, PhD, Abstract Co-Author: Nothing to Disclose

CT is considered the imaging modality of first choice for assessing sigmoid diverticulitis, in particular because of its ability to show the extraluminal inflammatory process. This study compares the extent of inflammation depicted by computed tomography with the gold standard histopathology. 

Preoperative CT findings of 91 patients (43 men and 48 women; median age 60.4 years) who underwent resection for sigmoid diverticulitis from August 2008 to May 2010 were compared to histological reports applying the Hansen and Stock classification (HS). All CT scans were evaluated in a dedicated study reading by two experienced radiologists. The interobserver agreement was determined by using the kappa index.

Nine patients were staged type I in the preoperative CT scan (sensitivity: 33%, specificity: 100%). Sensitivity and specificity for detecting a phlegmonous diverticulitis (HS IIA; n=6) was 83.3% and 83.5%, for detecting a covered perforation (HS IIB; n=49) 71.4% and 81.0% and for revealing a free perforation (HS IIC; n=5) 100% and 100%, respectively. Sensitivity and specificity for detecting a recurrent diverticulitis (HS III; n=22) was 72.7% and 92.7%. Kappa statistics revealed a moderate interobserver agreement (kappa=0.6), especially in cases of phlegmonous and covered perforation diverticulitis. In 10 patients (24%) CT did not reveal covered perforation which was histopathologically verified.

CT is an appropriate tool for diagnosing sigmoid diverticulitis. However, moderate inter-observer agreement reveals potential inaccuracies in the correct staging of sigmoid diverticulitis as compared to histopathology. A tendency to understage covered perforations (HS IIb) was found.

Since covered perforation may be not adequately revealed by CT in all cases, phlegmonous diverticulitis may also be regarded as complicated and consequently treated similar to covered perforation.

Sauer, A, Platzer, I, Schmid, J, Weng, A, Bley, T, Kenn, W, Retrospective Analysis of CT Staging in Sigmoid Diverticulitis by Using the Hansen and Stock Classification: Comparison of Preoperative CT Results with Histological Findings.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013094.html