Spectral CT Detection of Entrapped Gallstone Based on Z-effective Map

Abstract

of gallbladder stone (GBS) is based on ultrasound (US), due to its high accuracy (98%) [1]. When cholecystitis is clinically suspected, US is also the preferred first diagnostic method, to identify signs of inflammation and the causative stone [2]. In inconclusive cases, computed tomography (CT) can be required to confirm or exclude cholecystitis, with a lower accuracy for stone detection, ranging from 25-88 % [3]. The most recent spectral CT systems (dual-energy or spectral systems) are based on the principle of image acquisition at two levels of energy (80 and 140 kVp). In vitro studies dedicated to GBS have demonstrated that higher voltages could help CT to detect more GBS. Some CT manufacturers have developed software solutions giving access to mean atomic number values of anatomic structures. Here we present a case of a patient with a final and diagnosis of entrapped gallstone causing subacute cholecystitis. This was detected first with spectral CT and the use of the mean atomic number display map of the gallbladder content.

Detection of gallstone-related disease using dual-energy CT and effective atomic number analysis

“…The utility of dual-energy CT in gallstone evaluation is currently uncertain and the available dual energy analysis tools are therefore not being routinely utilised by the reading radiologists at our hospital. Emerging studies have suggested that dual-energy CT technology, with the help of postprocessing analysis tools, may have the potential to increase the conspicuity of radiolucent gallstones, thereby improving visual detection [5]. Many studies have described the use of low (40 keV) and high (140 keV) keV monoenergetic reconstructions in visualising radiolucent gallstones with varying success [6-8].…”

“…Cholesterol gallstones have a lower atomic number than bile. This difference in atomic number can be exploited to enhance their visibility on dual energy CT through applying colour LUT (Lookup Table ) overlays, selectively displaying all the atomic numbers within the available step gradients offered on the post processing software [5,7]. If DECT could effectively diagnose cholelithiasis and choledocholithiasis, this would reduce the need for further imaging using ultrasound and MRCP, permit earlier de nitive clinical decision making, decrease the length of hospital stay and reduce resource consumption.…”

Accuracy of Ultrasound and Magnetic Resonance Cholangiopancreatography Findings in the Diagnosis of Biliary System Stones

“…Many researchers have reported that computed tomography can help in detecting GB stones, especially with difficult and inconclusive cases or GB perforation, and is still recommended for abdominal pain evaluation, only if the diagnosis is uncertain (Harraz & Abouissa, 2020;Danse et al, 2018;Wertz et al, 2018). On the contrary, a CT scan is less accurate than ultrasound (US) imaging in detecting biliary stones and debatably the most effective for diagnosing gallbladder condition, especially for gallstone ileus and pancreaticobiliary tract evaluation (Veronica et al, 2019;Alshargi et al, 2018).…”