E2259. Detection of Cholesterol Gallstones Using Dual Energy Computed Tomography
  1. Poojitha Reddy; Albany Medical Center
  2. Erik Jacobson; Albany Medical Center
  3. April Zealor; Albany Medical Center
  4. Cody Brewster; Albany Medical Center
  5. Michael Schuster; Albany Medical Center
Gallstone disease has a prevalence of 10 - 15% in the United States and is one of the most common indications for hospital admission. Gallstones are concretions of materials precipitated out of bile and primarily described as cholesterol, pigmented, or mixed stones. Cholesterol stones have a cholesterol content of at least 50 %. Pigmented stones are composed of calcium bilirubinate. Cholesterol stones, along with mixed stones (cholesterol content of 20 - 50%), make up 80% of gallstones in the United States. The goal of this presentation is to discuss techniques to better visualize cholesterol stones which may aid in diagnosis of biliary pathology.

Educational Goals / Teaching Points
While many patients presenting with acute abdominal pain will undergo evaluation with computed tomography (CT), it is a relatively insensitive examination for gallbladder disease (39% compared to 83% for ultrasound). One of the major drawbacks to CT is that due to up to 57% of stones have a composition that is isoattenuating to bile, which severely limits their identification. However, ultrasound is also limited due to insensitivity of evaluation of stones in the common bile duct. Conversely, CT reconstructions can be manipulated to better evaluate the majority of the common bile duct in a single plane. Dual energy computed tomography (DECT) can further improve detection of isoattenuating cholesterol stones.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
DECT involves acquisition of two data set using a high and low kVp. Pre-determined attenuation curves for various materials differ over a spectrum of kVp and may be used to increase conspicuity of materials with similar attenuation on traditional CT. Therefore, using known curves for fat and water, it is possible to create a color overlay in order to visualize cholesterol stones which often have a similar attenuation as bile.

DECT can improve detection of isoattenuating cholesterol stones and has the ability to evaluate both the gallbladder and common bile duct.