ED patients often undergo abdominal CT as the initial imaging examination for nonspecific abdominal pain. The purpose of this study was to assess differences in the dual energy CT (DECT) iodine content of pericholecystic hepatic parenchyma and of the gallbladder wall in acute cholecystitis compared with controls.
METHOD AND MATERIALS17 patients (10M, 7F) who underwent cholecystectomy with pathology confirmed acute cholecystitis were included in this IRB approved, HIPAA compliant study. All patients underwent contrast enhanced DECT on a dual-source 128x2 slice scanner (Siemens FLASH) with either 80/Sn140 or 100/Sn140 kV pairs depending on patient size. Within 3 mm reconstructed slices, the following regions of interest (ROI) were placed on iodine overlay images to measure dual energy iodine concentration derived from three material decomposition: 1 cm2 hepatic parenchyma around the gallbladder fossa, 1 cm2 hepatic parenchyma in a different hepatic segment, and 5 mm2 on the gallbladder wall. These values were normalized to the iodine concentration in a main portal vein ROI to calculate a normalized iodine concentration. Measurements were compared to 20 control patients who underwent DECT without gallbladder pathology. Normalized iodine content in each of the three ROI locations was compared between the two groups using a t-test.
RESULTSThere was no significant difference between cholecystitis and control patients in normalized iodine content within the hepatic parenchyma remote from the gallbladder fossa (p=0.72). However, compared with controls, acute cholecystitis patients demonstrated higher normalized iodine concentration values within the hepatic parenchyma of the gallbladder fossa and within the gallbladder wall (p<0.001 for both comparisons).
CONCLUSIONDECT can detect increased pericholecystic hepatic parenchymal and gallbladder wall iodine content in patients with acute cholecystitis. Further work is needed to determine appropriate threshold values of iodine content that may aid in the diagnosis of acute cholecystitis.
CLINICAL RELEVANCE/APPLICATIONCholecystitis patients demonstrate increased iodine content within the gallbladder wall and pericholecystic hepatic parenchyma by Dual Energy CT. This may prove helpful in improving CT diagnosis of acute cholecystitis.
Honored Educators Presenters or authors on this event have been recognized as RSNA Honored Educators for participating in multiple qualifying educational activities. Honored Educators are invested in furthering the profession of radiology by delivering high-quality educational content in their field of study. Learn how you can become an honored educator by visiting the website at: https://www.rsna.org/Honored-Educator-Award/
Aaron D. Sodickson, MD, PhD - 2014 Honored Educator