Hepatobiliary and pancreatic: Commentary.

Abstract

Journal of Gastroenterology and HepatologyVolume 16, Issue 2 p. 228-229 Free Access Hepatobiliary and pancreatic: Commentary First published: 21 December 2001 https://doi.org/10.1046/j.1440-1746.2001.2436b.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat INTERPRETATION OF FIG. 1 (SEE PAGE 225) This sonogram shows an ill-defined gallbladder. The gallbladder wall is not clearly discerned, but the anterior portion of the bladder is hyperechoic, suggesting calcification or calcific stones. There is acoustic shadowing (S). The distinct finding is two parallel hyperechoic lines (arrow) that disappeared when the transducer was angled slightly to either side, a characteristic echo feature of a stone with fissures within it. Such fissures contain gas or fluid. The anterior line is the reflection from the stone surface, and the posterior line the reflection from the interface of stone and gas as illustrated in Fig. 2. Note that these two linear echoes are also casting a shadow. Gas reduces specific gravity and the stone floats toward the anterior surface in the supine position as seen on the CT (Fig. 3, thick arrow). This CT also shows several smaller ill-defined stones (thin arrow) posterior to the gas-containing stone. They are not calcific and perhaps represent pigment stones. Figure 2Open in figure viewerPowerPoint Stone fissures and sonogram (reproduced with permission4). Figure 3Open in figure viewerPowerPoint Computed tomography. Gas-containing stone (thick arrow) located anteriorly (floating) and posteriorly located non-calcific stones (thin arrow) are recognized. DIAGNOSIS: GAS-CONTAINING GALLSTONE Gas-containing stones are not uncommon. Hinkel studied 100 consecutive cholecystectomies and found fissures in the associated gallstones in 48 cases; 15 of them contained gas.1 The gas consists of 0.5% O2, 6–7.5% CO2 and the remainder N2.2 Radiating fissures occur in non-opaque stones within a radiating crystalline structure (Fig. 2a,b). The fissure is believed to develop as the crystalline structure shrinks, but bacteria can possibly be involved in other types of gas-containing stones. The fissures may be recognized on a plain film as the Mercedes–Benz sign3 and, in fact, plain abdominal film of this patient demonstrated indiscrete, but recognizable air. A lateral film did not show a fluid level, confirming gas rather than fluid. The outer layer of the stone can be calcific as in this patient. The form of the gas-containing lumen is not necessarily stellate, and in this patient two more stones with a calcific surface contained non-stellate gas. According to Tsuchiya, the interface between the stone and gas produces a reverberation that may be parallel to the surface reflection of the stone, producing two strong linear echoes, sometimes with multiple reflections as an artefact shown in Fig. 2c.4 Thus, this patient had two different types of gallstones, non-opaque pigment stones and mixed stones with a calcific outer-layer and gas-containing cracks or a cavity. REFERENCES 1 Hinkel CL. Fissures in biliary calculi. Am. J. Roentgenol. 1954; 71: 979 – 87. 2 Fulton H. Gas-containing gall stones. Gastroenterology 1955; 28: 862 – 6. 3 Meyers MA & O'Donohue N. The Mercedes-Benz sign: insight into the dynamics of formation and disappearance of gallstones. Am. J. Roentgenol. 1973; 119: 63 – 70. 4 Tsuchiya Y. Treatment of gallstones—Fragmentation and dissolution (in Japanese). Tokyo: Igaku-Shoin, 1997; 16 – 41. Volume16, Issue2February 2001Pages 228-229 FiguresReferencesRelatedInformation