Kyung Jin Lee MD, Presenter: Nothing to Disclose

Sang Won Kim MD, Abstract Co-Author: Nothing to Disclose

Hyun Cheol Kim, Abstract Co-Author: Nothing to Disclose

Dal Mo Yang, Abstract Co-Author: Nothing to Disclose

To evaluate the incidence of cystic duct enhancement on CT in acute cholecystitis, and to determine the usefulness of this finding for diagnosing acute cholecystitis in cases without visible impacted gallstones.

The institutional review board approved this study, and informed consent was waived. CT scans of 63 patients with surgically proven acute cholecystitis and 63 age- and sex-matched control subjects were retrospectively reviewed independently by two radiologists to determine the presence of the cystic duct enhancement or impacted stones in the gallbladder neck or cystic duct. Then, two additional radiologists were asked to evaluate independently all CT images using a 5-point scoring system for diagnosing acute cholecystitis, both before and after being informed of cystic duct enhancement in substitution for impacted gallstones. Pathologic correlation was performed in cases with acute cholecystitis in which two reviewers agreed on the presence of cystic duct enhancement.

Incidences of cystic duct enhancement and stone impaction were observed to be significantly more common in the patient group (86-91%) than in the control group (6-14%) (P < 0.001) with good interobserver agreement (κ = 0.79). Using the criterion in which acute cholecystitis is diagnosed when confidence score is four or five, diagnostic sensitivities increased significantly from 60.3% to 85.7% for reviewer 1 (p = 0.001) and from 71.4% to 87.3% for reviewer 2 (p = 0.028) after the reviewers were inform of cystic duct enhancement in substitution for impacted gallstones. Also, diagnostic accuracy increased significantly for the lesser experienced radiologist (from 75.4% to 87.3%, p = 0.015). Pathologically, cystic duct enhancement is correlated with either preserved mucosa of the cystic duct, in cases where the mucosal layer of the gallbladder is necrotized, or inflammation of the cystic duct similarly to that of the gallbladder.

Accuracy and sensitivity for diagnosing acute cholecystitis by CT were significantly improved when cystic duct enhancement was used as a complement to impacted gallstones.

When cystic duct enhancement and impacted gallstones are used complementarily as major CT findings, the diagnostic sensitivities of CT increased significantly from 60-71% to 86-87%, which are comparable with those of US (81%) and MR (85%).

Lee, K, Kim, S, Kim, H, Yang, D, Cystic Duct Enhancement: A Useful CT Finding in the Diagnosis of Acute Cholecystitis without Visible Impacted Gallstones.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14006492.html