Young Hwan Lee MD, Abstract Co-Author: Nothing to Disclose

Youe Ree Kim MD, Presenter: Nothing to Disclose

Seong Hyun Wee MD, Abstract Co-Author: Nothing to Disclose

Dong-Ho Bang MD, Abstract Co-Author: Nothing to Disclose

Kwon-Ha Yoon MD, PhD, Abstract Co-Author: Nothing to Disclose

The aim of this study was to differentiate cholesterol gallstone from calcium gallstone using dual energy CT(DECT) and to correlate with in-vitro phantom study.

We retrospectively analysed 95 gallstones in 48 patients with in-vitro and clinical DECT. Semi-quantitative infrared spectroscopy (FTIR) was performed to confirm the chemical composition of the stones. According to the FTIR results, gallstones were divided into calcium and cholesterol stones, we measured Hounsfield units (HU) of the gallstones at 80, 100, 140kVp image sets of in-vitro DECT and calculated sensitivity for stone detection. We also measured HU values of the 60 stones (25 cholesterol stones, 35 calcium stones) at 100, 140, Mixed kVp sets and virtual non-enhanced (VNE) images of clinical DECT and calculated sensitivity for stone detection. Finally we compared the HU values of stones on each image sets.

 Gallstones were confirmed as 45 cholesterol stones in 23 patients and 50 calcium bilirubinate stones in 25 patients on FTIR. On in-vitro DECT analysis, cholesterol stones were identified with 100%, 84%, 96% sensitivities and calcium stones were identified with 98%, 98%, 98% sensitivities at 80, 100, 140kVp image sets. Cholesterol stones showed hypoattenuation at 80kVp (76%), hyperattenuation at 140kVp (51%). Calcium stones showed hyperattenuation at all of image sets (98%). There were statistically significant at all of the comparative quantitative analyses of 80/100kVp, 80/140kVp and 100/140kVp sets (for cholesterol stones, P<.001; for calcium stones, P<.001). On clinical DECT image analysis, detection sensitivities of cholesterol stones were 62%, 77%, 60%, 93% and sensitivities of calcium stones were 97%, 97%, 97%, 97% at 100, 140, mixed kVp, VNE image sets, respectively. There were also statistically significant at comparative quantitative analyses of 100/140kVp set for cholesterol stone (P=.049), of 100/140kVp and 100/mixed kVp sets for calcium stones (P<.001, P=.001)

Cholesterol stones usually showed iso- or hyperattenuation at high kVp images than low kVp images and calcium stones showed hyperattenuation at all kVp images of DECT. VNE images of clinical DECT were useful to detect cholesterol gallstones.

Dual energy CT can be used to differentiate gallstone components with different kVp setting and detection of cholesterol gallstones can be improved on virtual non-enhanced images of DECT.

Lee, Y, Kim, Y, Wee, S, Bang, D, Yoon, K, Gallstone Characterization Using Dual Energy Computed Tomography and Correlation with in-vitro Phantom Study.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013057.html