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IMAGING OF GALLBLADDER VARIANTS H MHALLA (1), S MEZGHANI BOUSSETTA (1) Department of radiology (1) Hospital of Ben Arous. Tunisia.

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Presentation on theme: "IMAGING OF GALLBLADDER VARIANTS H MHALLA (1), S MEZGHANI BOUSSETTA (1) Department of radiology (1) Hospital of Ben Arous. Tunisia."— Presentation transcript:

1 IMAGING OF GALLBLADDER VARIANTS H MHALLA (1), S MEZGHANI BOUSSETTA (1) Department of radiology (1) Hospital of Ben Arous. Tunisia

2 INTRODUCTION Routine imaging of the gallbladder demonstrates a wide array of imaging variants, including anomalies in location, number, and configuration. An awareness of these normal variants may prevent misdiagnosis and will aid in evaluation of alternative diagnostic possibilities.

3 OBJECTIVES The aim of this study is to describe different radiologic findings of gallbladder variants and embryological events leading to these variants.

4 MATERIALS AND METHODS Retrospective study of five patients. All of them have consulted in regional hospital of Ben Arous. Abdominal US exam performed for each of them revealed gallbladder anomalies.

5 RESULTS AND DISCUSSION The mean age was 26 years (8 months- 48 years), clinical symptoms were right upper quadrant pain (4 cases) for 6 months (2 cases), acute pain (2 cases) and radiological discovery without clinical symptoms (1 case). 3 patients had congenital anomalies; mega-urethra (1 case), situs inversus (1cas), congenital scoliosis (1 case). Gallbladder variants were anomalies in location (2 cases) retrohepatic and left gallbladder, anomalies of number (2 cases) agenesis and duplicity and anomalies of configuration (1 case) junctional fold gallbladder.

6 We can notice different gallbladder variants. Anomalies of number such as duplicity, accessory, agenesis or triplication, in location such as left sided, suprahepatic, intrahepatic, retroplaced and mobile gallbladder, and of configuration such as multiseptate and junctional fold gallbladder. For a better understanding of these variants, we need to understand the events occurring at the embryological period.

7 Embryology In the fourth week of fetal development, the hepatic diverticulum appears as a cellular outgrowth of the proximal part of the intestinal tube. The hepatic diverticulum arises as a sacculation consisting of a cranial portion which further differentiates into glandular tissue and bile ducts. The main portion of the hepatic diverticulum elongates to form the common bile and hepatic ducts. The caudal portion of the hepatic diverticulum becomes the gallbladder and cystic duct. The gallbladder is a solid epithelial cylinder which is carried from the duodenum by the elongated common duct. In the seventh week, a lumen is established within the cystic duct.

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9 Anomalies in Number Agenesis of the gallbladder is rare, as are duplication anomalies. Triplication gallbladder is exceptional. Duplicated Gallbladder The phenomenon is explained by the duplication of the gallbladder vesicle. Gallbladder duplication is a rare anomaly. Boyden’s classification of double gallbladders includes: (1) bilobed incomplete gallbladder division with one cystic duct (2) complete gallbladder duplication with separate cystic ducts entering the common hepatic duct (Figure 1) (3) complete gallbladder duplication with a common cystic duct entering the common hepatic duct.

10 Figure 1: Ultrasonography showing two gallbladders with separate ducts (Type 2 of Boyden’s classification).

11 Differentiation between the specific types of duplication is usually not possible with sonography. When stones are present, they may be sequestered in one of the two lobes. When gallstones can be demonstrated to communicate with all parts of the gallbladder, a folded gallbladder is more likely than duplication. A more specific sign of gallbladder duplication may be isolated contraction of the non-diseased lobe with an absence of contraction of the diseased lobe. This finding may be useful for differentiating between two gallbladder lobes and other forms of pericholecystic fluid collection. It may also suggest at least partial duplication of the cystic duct, since a patent cystic duct must be present to contract the lobe.

12 Accessory Gallbladder Boyden presented two theories explaining accessory gallbladder formation: - The first suggests that the phenomenon is caused by the primary subdivision of the embryonic primordium into two parts, and accessory gallbladders represent an outgrowth of a secondary vesicle from some other portion of the biliary duct system subsequent to the formation of a definitive gallbladder. - The second theory supports the idea that bile duct buds occur at the junction of the hepatic ducts. These duct buds usually regress and disappear. However, if they persist, gallbladder anomalies such as duplication or triplication may occur. If the bud originates on one of the hepatic or common ducts, the accessory gallbladder will contain its own cystic duct. If the bud originates from the cystic duct, a Y-shaped cystic duct will connect the accessory and the normal gallbladder to the common duct. Pseudo duplication gallbladder may simulate a double gallbladder.

13 Agenesis of gallbladder (Figure 3) The development of the liver and gallbladder system starts around the third week of gestation, when the primordial liver, called the hepatic diverticulum, is formed as an outgrowth of the endodermis of the anterior intestine. As the diverticulum grows, its connection with the intestine narrows to form the external hepatic bile duct. A small ventral invagination grows in this narrow area and gradually forms a vacuole that becomes the gallbladder and cystic duct. A failure of this invagination results in agenesis of the gallbladder.

14 Figure 3: A, B: T2 axial slices, C: sequence RARE both showing agenesis of gallbladder which appears as a stump.

15 Triplication of Gallbladder Triplication of the gallbladder is a very rare congenital anomaly of the biliary tract. Gallbladder multiplications are not likely to be discovered unless associated with cholelithiasis, sludge, cholecystitis and carcinoma. Multiple gallbladders are thought to be caused by the failure of rudimentary bile ducts to regress during embryological development. Three distinct types are described: -The first type is characterized by the presence of multiple gallbladders that drain into the common bile duct via separate cystic ducts. - The second type is characterized by the presence of two gallbladders with a common cystic duct entering the common duct, and a third gallbladder with an independent cystic duct. -The third type is characterized by the presence of three gallbladders that share a single cystic duct.

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17 Anomalies in location Normally, the gallbladder is adjacent to the undersurface of the liver, in the plane of the interlobar fissure, with the gallbladder neck maintaining a constant relationship to the porta hepatis. The gallbladder is routinely found in the right upper quadrant, but may be seen in any part of the abdomen. While anomalies of positions are rare, the most common of these are the left sided, intrahepatic, transverse, and retroplaced (retrohepatic or retroperitoneal).

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19 A left-sided gallbladder location is seen in situs inversus (Figure. 4). A gallbladder in the left upper quadrant without situs inversus is even rarer. There are several explanations for that: -The first is that, the normal gallbladder bud may migrate to the left lobe instead of the right, and lie on the left side of the ligamentum teres. In this situation, the portal vein, biliary tree and hepatic artery should be in the normal location and classified as an ectopic gallbladder. - The second suggests that, the gallbladder may develop directly from the left hepatic duct, and is accompanied by a failure in the development of the normal structure on the right side. -Third, the left umbilical vein disappears and the right one partly remains. -The fourth explanation is that, the gallbladder is on the left side of the ligamentum teres simply because the latter deviated to the right. The left-sided gallbladder may occur either as a single anomaly or in a malrotation of the intestine

20 Figure 4: CT injected axial slices showing ectopic gallblader with gallstone associated with situs inversus

21 Intrahepatic gallbladders Have a subcapsular location along the anterior inferior right lobe of the liver. This poses a problem for scintigraphy, as an intrahepatic gallbladder can cause a focal defect. When a solitary defect is present in a technetium liver scan, the differential diagnosis includes neoplasm, abscess, hematoma, lymphoma, and an aberrant gallbladder. Sonography can be helpful in these cases.

22 Suprahepatic gallbladder The suprahepatic gallbladder is a rare type of gallbladder ectopia, with only approximately eight cases reported. Most of these patients have either associated hypoplasia of the right hepatic lobe or a right-sided diaphragmatic eventration. A suprahepatic gallbladder has been reported with hepatomegaly due to macronodular cirrhosis. Rarely, the suprahepatic gallbladder may be intrathoracic, and be associated either with a right-sided diaphragmatic eventration or a traumatic right-sided diaphragmatic hernia. It may be located either anteriorly or posteriorly over the dome of the right hepatic lobe. As with many other ectopic gallbladder locations, it usually has a mesentery that allows it to float freely in the peritoneal cavity. The cystic duct and vascular supply of the gallbladder in a suprahepatic location insert normally.

23 The retroplaced gallbladder (retrohepatic) (Figure. 5) Is rare and can be either congenital or acquired. Gallbladder rotation and/or displacement can be caused by hepatic lobe abnormalities (aplasia, hypoplasia, and hypertrophy) and by abnormal mobility of the gallbladder itself. From an imaging standpoint, it is important to realize that when the gallbladder is not visualized in its normal location, the possibility of an ectopic location must be considered.

24 Figure 5: A: ultrasonography, B: CT, C: schematic representation, showing retrohepatic location of gallbladder.

25 A mobile Gallbladder May have different causes. One type of anomaly may be related to the congenital deformity. Between the fourth and the seventh week of embryological development, the pars cystica forms from the hepatic diverticulum. Abnormal migration with an absence of a gallbladder mesentery creates a “free floating gallbladder”. Another anomaly occurs with generalized visceroptosis. The mesentery of the gallbladder and cystic duct relax and elongate, thus creating a mobile situation. These anomalies leading to “floating gallbladder” can be responsible for complications such as torsion or volvolus.

26 Anomalies in Form Junctional fold gallbladder Several variations in the radiologic appearance of gallbladder shape have been described. The so-called junctional fold is folding of the gallbladder, usually of the posterior wall, but can occur anteriorly as well. Such junctional folds occur frequently, and are easily shown by sonography as well as by other imaging techniques. Careful analysis usually excludes adjacent disease. The Phrygian cap is a typical. It takes its name from the ancient Greek headgear, descriptive of this asymptomatic folding of the gallbladder fundus. This variant is readily identified with sonography and CT. Septa of the gallbladder can be either partial or complete. These can lead to stasis and stone formation.

27 Multiseptate gallbladder (Figure 6) Is a rare anomaly, having a multichambered lumen with multiple septa, creating a honeycombed appearance. Differential possibilities on sonography include desquamated gallbladder mucosa, and possibly polypoid cholesterolosis. The coexistence of biliary symptoms with multiseptate gallbladder has been well established, and most patients have biliary pain suggestive of cholecystitis Gallbladders containing one to three septa are not unusual. The exact mechanism responsible for the genesis of multiseptation is not clear. However, it is speculated that wrinkling and infolding seen in the gallbladder buds of cat and guinea-pig embryos or formation of the so-called Phrygian cap in human embryos may be related to this phenomenon.

28 Figure 6: Ultrasonography showing some locules formed by the transversal septas.

29 CONCLUSION Radiological diagnosis of biliary anomalies is an important part of abdominal imaging. In daily practice, biliary anatomy may be demonstrated with a wide range of techniques, such as high resolution US, multislice CT and MRCP. Preoperative awareness of any variation minimizes the chance of an unexpected situations during cholecystectomy, and helps avoiding any unwanted damage to the biliary tract.

30 REFERENCES 1- Sonography of Gallbladder Duplication and Differential Considerations Robert C. Goiney1, Steven A. Schoenecker2, Dale A. Cyr2, William P. Shurnan2, Michael J. Peters2, Peter L. Cooperberg3. A JR 145:241-243, August 1985 0361-803X/85/1452-0241© American Roentgen Ray Society. 2- Triplication of the gallbladder Ronald j. Ross, MD, and Maurice D. Sachs, M.D From the Department of Radiology, Forest City Hospital, Case- Western Reserve University School of Medicine, Cleveland, Ohio.. VoL. 104, No. 3 3- Agenesis of the gallbladder and cystic duct Serviço de Gastroenterologia Cirúrgica, Hospital do Servidor Público Estadual, São Paulo, Brazil. Jaques Waisberg, Paulo Engler, Pinto Júnior, Paula Regina Gusson, Paola Rossini Fasano, Antônio Cláudio de Godoy. 4- Agenesis of gallbladder and multiple anomalies of the biliary tree in a patient with portal thrombosis: A case report Yusuf BAYRAKTAR 1, H. Yasemin BALABAN 1, Serap ARSLAN 1, Ferhun BALKANCI 2 Departments of 1 Gastroenterology and 2 Radiology, Hacettepe University, Ankara. The Turkish Journal of Gastroenterology 2006, Volume 17, No 3, Page(s) 212-215 5-Triplication of the gallbladder. Banu Alicioglu, Department of Radiology, Trakya University School of Medicine, Edirne 22030, Turkey. World J Gastroenterol. 2007 Apr 7; 13 (13) 2004-6. 6- Left-sided gallbladder associated with congenital liver cyst. R. COLOVIC1, N. COLOVIC1, G. BARISIC1, H. D. E. ATKINSON2 & Z. KRIVOKAPIC1. ISSN 1365-182X print/ISSN 1477-2574 online # 2006 Taylor & Francis DOI: 10.1080/13651820410016642 7- Left-sided gallbladder: Its clinical significance and imaging presentations Sheng-Lung Hsu, Tai-Yi Chen, Tung-Liang Huang, Cheuk-Kwan Sun, Allan M Concejero, Leo Leung-Chit Tsang, Yu-Fan Cheng. 8- The Aberrant Gallbladder: Angiographic and Radioisotopic Considerations VINCENT P. CHUANG. Am J Roentgenol 1 27 : 41 7-421. 1976 417 9- Gastrointestinal Case of the Day Kenneth D. Hopper,1 Mary Ellen Fisher, Claudia J. Kasales, Paul S. Potok, Jon W. Meilstrup, and Daniel B. Kelley. AJR 1994;162:1448-1451 0361-803X/94/1626-1448 ©American Roentgen Ray Society. 10- Torsion of Gallbladder: Report of a case. Yon Pil Cho and al. Yonsei Med J Vol. 46, No 6, 2005. 11- Imaging of Gallbladder Variants Jon W. Meilstrup,1 Kenneth D. Hopper, and Gary A. Thieme. AJR 157:1205-1208, December 1991 0361 - 803X/91/1 576-1 205 C American Roentgen Ray Society. 12- Multiseptate Gallbladder with Cholelithiasis Diagnosed Incidentally in an Elderly Patient. Wataru Miwa, Kyutaro Toyama, Yoko Kitamura, Kazuko Murakami, Kazuhisa Kamata, Tessyu Takada, Hiroaki Tanabe and Masaaki Kanayama. Internal Medicine Vol. 39, No. 12 (December 2000).


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