Development of a Novel CT Tool to Identify Cholecystitis

Abstract

Background: Cholecystitis is a frequent surgical problem presenting via the emergency department. While clinical signs and symptoms are suggestive of cholecystitis, imaging is usually used as a diagnostic adjunct. Ultrasound (US) has been the modality of choice for evaluating the gallbladder; however the use of computed tomography (CT) has been increasing, particularly in emergency departments (ER). Unfortunately, there is limited data elucidating which CT findings identify cholecystitis. This study sought to identify specific CT findings that were easily identified even by nonexperts to aid in developing a checklist instrument to accurately diagnose acute cholecystitis using CT. Methods: We utilized CT scans of patients admitted through the ER who underwent CT scan as well as US and surgical cholecystectomy during the same admission from June 2010-December 2011. Data recorded included details from imaging and pathology reports. Based on previous literature, we created a 23 point checklist of CT findings in acute cholecystitis. A surgeon, blinded to all patient data, used this checklist in yes/no fashion to interpret the CT scans for diagnosis of cholecystitis. Using the diagnosis of cholecystitis by pathology as gold standard, sensitivities for checklistassisted CT, standard read CT and US, and individual imaging findings on CT scans were calculated. Results: Ninety-two patients were included in the study. When evaluating both acute and chronic cholecystitis, the sensitivity for US was 32.9%; the standard CT was 27.0% and checklist-assisted CT was 60.7%. When evaluating only acute cholecystitis, sensitivities were 47.1% for US, 42.9% for standard CT and 76.2% for checklist-assisted CT. Most sensitive findings on the checklist included presence of gallbladder distention (46.1%) sub-serosal halo/wall edema (38.2%), gallstones (37.1%), sludge (37.1%) and irregular/absent wall (32.6%). Conclusion: The use of a checklist improved detection of acute and chronic cholecystitis, even when used by a nonexpert, suggesting that this is a useful tool in evaluation of the disease.