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GI RADIOLOGY Table of Contents   
Year : 2007  |  Volume : 17  |  Issue : 2  |  Page : 74-76
Depiction of lesser sac anatomy on MDCT by extravasated oral contrast in a case of gastric perforation

Department of Radiodiagnosis, Ruby Hall Clinic, Pune, India

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Keywords: Gastric perforation, lesser sac anatomy, MDCT

How to cite this article:
Atre A L, Tandon A, Unune N. Depiction of lesser sac anatomy on MDCT by extravasated oral contrast in a case of gastric perforation. Indian J Radiol Imaging 2007;17:74-6

How to cite this URL:
Atre A L, Tandon A, Unune N. Depiction of lesser sac anatomy on MDCT by extravasated oral contrast in a case of gastric perforation. Indian J Radiol Imaging [serial online] 2007 [cited 2021 Feb 25];17:74-6. Available from:
The peritoneal cavity contains a series of communicating but compartmentalized potential spaces that are not visualized on CT scans unless they are distended by fluid. Knowledge of the anatomy of these spaces and of the ligaments that define them is important in our understanding of pathological processes involving the peritoneal cavity especially after the advent of multi-detector CT (MDCT). One such potential space is the lesser peritoneal sac, which has long been of interest to radiologists. Disease processes producing generalized ascites or those involving the pancreas, transverse colon and posterior wall of the stomach, posterior wall of duodenum and the caudate lobe of the liver can produce pathological changes in the lesser sac. A case of gastric ulcer perforation was encountered at our institution, in which after administration of oral water-soluble contrast, not only was the exact site of perforation demonstrated but there was also an excellent depiction of the lesser sac anatomy due to contrast extravasation.

   Case Report Top

A 65-years-old woman who had a history of fever and abdominal pain for 20 days, presented with diarrhea. Ultrasound (USG) revealed moderate free fluid in the abdomen for which an intraperitoneal drain was kept. There was seropurulent discharge from the drain on the second day and the patient was referred for CT scan to look for any cause of sepsis or perforation.

CT scan was performed with a 40 slice MDCT unit (Philips Brillance-40 Mumbai), using the following scan parameters: 2 mm collimation, 1 mm reconstruction interval and a pitch factor of.825, 120 kV tube voltage and 200 mAs tube current. Images were obtained after oral and intravenous administration of a water-soluble contrast. The CT scan revealed extravasation of oral contrast into the lesser sac through the posterior gastric wall, in the region of the antrum, with an air-fluid level in the lesser sac. There was a moderate degree of ascites and large amount of free intraperitoneal air. CT anatomy of the lesser sac was well-depicted by the extravasated oral contrast on axial, coronal and sagittal images.

   Discussion Top

During the embryologic development of the alimentary tract, the stomach and duodenum rotate to the right to form a potential space between the stomach and pancreas, known as the omental bursa or lesser sac. [1] The lesser sac is that portion of the right hepatic space that is displaced as the liver grows to fill the right upper abdomen. [1] The right peritoneal space then moves medially behind the gastrohepatic ligament and stomach and is enfolded by the markedly redundant gastrosplenic ligament. [1]

The lesser sac communicates with the remainder of the right portion of the greater peritoneal cavity i.e. the perihepatic space via the foramen of Winslow. [1] This narrow inlet is bordered by the free edge of the hepatoduodenal ligament ventrally, the caudate lobe of the liver superiorly and the inferior vena cava posteriorly [1] [Figure - 1]A. This foramen, in our study was well-outlined by the extravasated oral contrast, on axial and coronal images [Figure - 1]A, C.

The lesser sac is divided into two major recesses by a diagonal fold of peritoneum reflecting posteriorly over the left gastric and hepatic arteries [2] [Figure - 2]A,D. The smaller superior recess is identified on transverse sections above the plane of the pancreas [Figure - 2]A. It completely encloses the medial surface of the caudate lobe [3] [Figure - 1]C. At the porta hepatis the superior recess lies just posterior to the portal vein [Figure - 2]A. On more cephalic sections, it lies immediately behind the lesser omentum deep within the fissure for the ligamentum venosum and follows the caudate lobe surface posteriorly and to the right extending almost to the inferior vena cava [Figure - 1]C. Near the diaphragm, the posterior part of this space lies adjacent to the right diaphragmatic crus, just inferior to the abdominal segment of the esophagus. This extent was better demonstrated on mid-sagittal reformatted images [Figure - 1]A. The larger inferior recess is located to the left of the midline and it lies between the stomach and the pancreas [4] [Figure - 2]C. It is bounded inferiorly by the transverse colon and its mesentery, but can extend for a variable distance between the anterior and posterior reflections of the greater omentum. [5] To the left, it is bounded by the gastro-splenic and lieno-renal ligaments, which meet at the splenic hilum. [5]

In addition to the excellent depiction of lesser sac anatomy, MDCT also helped us to locate the exact site of the perforation through the posterior gastric wall [Figure - 1]D,[Figure - 2]C[7].

   References Top

1.Dodds WJ, Foley WD, Lawson TL, Stewart ET, Taylor A. Anatomy and imaging of the lesser peritoneal sac. AJR Am J Roentgenol 1985;144:567-75.  Back to cited text no. 1  [PUBMED]  
2.Meyers MA. Dynamic radiology of the abdomen: Normal and pathological anatomy, 3 rd ed. Springer-Verlag: New York; 1988.  Back to cited text no. 2    
3.Raval B, Hall JT, Jackson H. CT diagnosis of fluid in lesser sac mimicking thrombosis of inferior vena cava. J Comput Assist Tomogr 1985;9:956-8.  Back to cited text no. 3  [PUBMED]  
4.Allen KS, Siskind BN, Burrell MI. Perforation of distal esophagus with lesser sac extension: CT demonstration. J Comput Assist Tomogr 1986;10:612-4.  Back to cited text no. 4  [PUBMED]  
5.Jeffery RB, Federle MP, Goodman PC. Computed tomography of lesser peritoneal sac. Radiology 1981;141:117-22.  Back to cited text no. 5    
6.Mellins HZ. The lesser peritoneal sac. In : Margulis AR, Burhenne HJ, editors. Alimentary tract roentgenology. Vol. 2. Mosby: St. Louis; 1973. p. 1182-93.  Back to cited text no. 6    
7.Hickey MC, Ghosh SK, Hugh AE. Radiology of the lesser sac. Clin Radiol 1973;24:162-5.  Back to cited text no. 7  [PUBMED]  

Correspondence Address:
Anurag Tandon
Dept. of Radiodiagnosis Ruby Hall Clinic 40, Sassoon Road Pune-411 001 Maharashatra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.33613

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