RadioGraphics
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

DOI: 10.1148/rg.273065085
This Article
Right arrow Abstract Freely available
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow CME Test (opens in a new window)
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Yoo, E.
Right arrow Articles by Kim, K. W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yoo, E.
Right arrow Articles by Kim, K. W.
Related Collections
Right arrow Computed Tomography
Right arrow Gastrointestinal Radiology

Greater and Lesser Omenta: Normal Anatomy and Pathologic Processes1

Eunhye Yoo, MD, Joo Hee Kim, MD, Myeong-Jin Kim, MD, Jeong-Sik Yu, MD, Jae-Joon Chung, MD, Hyung-Sik Yoo, MD, and Ki Whang Kim, MD

1 From the Department of Diagnostic Radiology (E.Y., J.H.K., M.J.K., J.S.Y., J.J.C., H.S.Y., K.W.K.) and Institute of Gastroenterology (M.J.K.), Yonsei University College of Medicine, Seodaemun-ku, Shinchon-dong 134, Seoul 120-752, Republic of Korea. Presented as an education exhibit at the 2005 RSNA Annual Meeting. Received May 2, 2006; revision requested July 24 and received September 11; accepted September 18. All authors have no financial relationships to disclose.

Figure 1A
View larger version (48K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1a.  Drawing of the anatomy of the greater and lesser omenta (a) and axial (b), coronal (c), and sagittal (d) diagrams of the upper abdomen. The greater omentum (GO) is composed of a double layer of peritoneum that extends from the greater curvature of the stomach (S) inferiorly. Its descending and ascending portions usually fuse to form a four-layer vascular fatty apron; the resulting space is contiguous with the lesser sac (LS). The lesser omentum (LO) connects the lesser curvature of the stomach and proximal duodenum with the liver (L) and contains blood vessels, nerves, and lymph nodes. The lesser sac is empty and collapsed so that only parts of its boundaries, such as the posterior gastric wall and pancreatic body, are observed on axial CT scans. Ao = aorta, C = colon, K = kidney, P = pancreas, Sp = spleen, 1 = falciform ligament, 2 = gastrohepatic ligament, 3 = gastrosplenic ligament.

 

Figure 1B
View larger version (41K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1b.  Drawing of the anatomy of the greater and lesser omenta (a) and axial (b), coronal (c), and sagittal (d) diagrams of the upper abdomen. The greater omentum (GO) is composed of a double layer of peritoneum that extends from the greater curvature of the stomach (S) inferiorly. Its descending and ascending portions usually fuse to form a four-layer vascular fatty apron; the resulting space is contiguous with the lesser sac (LS). The lesser omentum (LO) connects the lesser curvature of the stomach and proximal duodenum with the liver (L) and contains blood vessels, nerves, and lymph nodes. The lesser sac is empty and collapsed so that only parts of its boundaries, such as the posterior gastric wall and pancreatic body, are observed on axial CT scans. Ao = aorta, C = colon, K = kidney, P = pancreas, Sp = spleen, 1 = falciform ligament, 2 = gastrohepatic ligament, 3 = gastrosplenic ligament.

 

Figure 1C
View larger version (42K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1c.  Drawing of the anatomy of the greater and lesser omenta (a) and axial (b), coronal (c), and sagittal (d) diagrams of the upper abdomen. The greater omentum (GO) is composed of a double layer of peritoneum that extends from the greater curvature of the stomach (S) inferiorly. Its descending and ascending portions usually fuse to form a four-layer vascular fatty apron; the resulting space is contiguous with the lesser sac (LS). The lesser omentum (LO) connects the lesser curvature of the stomach and proximal duodenum with the liver (L) and contains blood vessels, nerves, and lymph nodes. The lesser sac is empty and collapsed so that only parts of its boundaries, such as the posterior gastric wall and pancreatic body, are observed on axial CT scans. Ao = aorta, C = colon, K = kidney, P = pancreas, Sp = spleen, 1 = falciform ligament, 2 = gastrohepatic ligament, 3 = gastrosplenic ligament.

 

Figure 1D
View larger version (40K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1d.  Drawing of the anatomy of the greater and lesser omenta (a) and axial (b), coronal (c), and sagittal (d) diagrams of the upper abdomen. The greater omentum (GO) is composed of a double layer of peritoneum that extends from the greater curvature of the stomach (S) inferiorly. Its descending and ascending portions usually fuse to form a four-layer vascular fatty apron; the resulting space is contiguous with the lesser sac (LS). The lesser omentum (LO) connects the lesser curvature of the stomach and proximal duodenum with the liver (L) and contains blood vessels, nerves, and lymph nodes. The lesser sac is empty and collapsed so that only parts of its boundaries, such as the posterior gastric wall and pancreatic body, are observed on axial CT scans. Ao = aorta, C = colon, K = kidney, P = pancreas, Sp = spleen, 1 = falciform ligament, 2 = gastrohepatic ligament, 3 = gastrosplenic ligament.

 

Figure 2A
View larger version (137K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 2a.  Peritoneal carcinomatosis in a 22-year-old man with epigastric pain. Axial (a) and coronal (b) CT scans show large amounts of ascites, diffuse nodular omental infiltration (omental cake) (arrows), and abnormal gastric wall thickening (arrowhead in b), findings compatible with carcinomatosis from the stomach.

 

Figure 2B
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 2b.  Peritoneal carcinomatosis in a 22-year-old man with epigastric pain. Axial (a) and coronal (b) CT scans show large amounts of ascites, diffuse nodular omental infiltration (omental cake) (arrows), and abnormal gastric wall thickening (arrowhead in b), findings compatible with carcinomatosis from the stomach.

 

Figure 3
View larger version (139K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 3.  Peritoneal carcinomatosis in a 30-year-old woman with malignant melanoma. CT scan shows hematogenous dissemination of malignant nodules in the peritoneal space including the omentum (arrows), retroperitoneal spaces, and the subcutaneous fat layer of the abdomen.

 

Figure 4
View larger version (128K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 4.  Tuberculous peritonitis in a 38-year-old woman with abdominal distention for 1 week. CT scan shows a large amount of ascites with even peritoneal thickening (arrowhead) and diffuse omental infiltration (arrow) without associated lymphadenopathy. The initial impression was carcinomatosis. When the primary malignancy is unclear, the differential diagnosis should include tuberculous peritonitis, particularly in endemic areas. The final diagnosis was tuberculous peritonitis.

 

Figure 5
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 5.  Malignant peritoneal mesothelioma in a 47-year-old man with dyspnea for 1 month. CT scan shows a diffuse, platelike mass in the greater omentum (arrows), massive ascites, and peritoneal thickening. Malignant mesothelioma was confirmed with pleural biopsy and cytologic analysis of peritoneal fluid.

 

Figure 6A
View larger version (145K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 6a.  Pseudomyxoma peritonei in a 47-year-old man with abdominal discomfort. Axial (a) and coronal (b) CT scans show multiple low-attenuation nodules and masses in the omentum and peritoneal cavity. Curvilinear or punctate calcifications of the seeding nodules; scalloping of the liver, spleen, and stomach; and small bowel adhesions from mesenteric infiltration are noted. Pseudomyxoma peritonei was proved with peritoneoscopic biopsy.

 

Figure 6B
View larger version (169K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 6b.  Pseudomyxoma peritonei in a 47-year-old man with abdominal discomfort. Axial (a) and coronal (b) CT scans show multiple low-attenuation nodules and masses in the omentum and peritoneal cavity. Curvilinear or punctate calcifications of the seeding nodules; scalloping of the liver, spleen, and stomach; and small bowel adhesions from mesenteric infiltration are noted. Pseudomyxoma peritonei was proved with peritoneoscopic biopsy.

 

Figure 7
View larger version (136K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 7.  Peritoneal lymphomatosis in a 71-year-old man with abdominal distention for 15 days. CT scan shows ascites in the pelvic cavity and innumerable seeding nodules in the peritoneal cavity and omentum (white arrow). Multiple enlarged lymph nodes with conglomeration (black arrows) are seen in the retroperitoneal spaces. Endoscopic gastric biopsy showed B-cell lymphoma, thus confirming the diagnosis of lymphomatosis.

 

Figure 8
View larger version (142K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 8.  Secondary neoplasm of the greater omentum in an 80-year-old woman with dyspepsia. Coronal CT scan shows a large lobulated mass (arrows) in the left upper quadrant of the abdomen. The mass represents an exophytic tumor from the greater curvature of the stomach, a finding suggestive of an exophytic gastric carcinoma.

 

Figure 9
View larger version (114K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 9.  Metastatic peritoneal tumor in a 73-year-old woman with a palpable abdominal mass for 2 months. CT scan shows a large, lobulated, heterogeneous mass in the midabdomen, inferolateral to the stomach. Thickened peritoneum (arrow) adjacent to the mass is suggestive of a malignant lesion. Metastatic carcinoma was confirmed at surgical excision. The patient had a history of ovarian carcinoma.

 

Figure 10A
View larger version (104K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 10a.  Abdominal lymphangioma in a 38-year-old woman with a gastric ulcer, which was an incidental finding at CT. Axial unenhanced (a) and coronal contrast-enhanced (b) CT scans show a lobulated cystic mass in the greater omentum inferior to the gastric antrum. The mass is most likely a cystic lymphangioma.

 

Figure 10B
View larger version (120K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 10b.  Abdominal lymphangioma in a 38-year-old woman with a gastric ulcer, which was an incidental finding at CT. Axial unenhanced (a) and coronal contrast-enhanced (b) CT scans show a lobulated cystic mass in the greater omentum inferior to the gastric antrum. The mass is most likely a cystic lymphangioma.

 

Figure 11A
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 11a.  Abdominal paragonimiasis in a 49-year-old man with hepatic lesions incidentally found during laparoscopic cholecystectomy. (a) CT scan shows multilocular cystic lesions in the right lobe of the liver. (b) CT scan shows multifocal ill-defined cystic lesions and several nodules (arrow) in the omentum on the right side of the abdomen. These appearances are suggestive of multilobulate parasitic abscesses in the liver with peritoneal seeding of parasitic granulomas. Biopsy of the liver and omentum demonstrated paragonimiasis.

 

Figure 11B
View larger version (132K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 11b.  Abdominal paragonimiasis in a 49-year-old man with hepatic lesions incidentally found during laparoscopic cholecystectomy. (a) CT scan shows multilocular cystic lesions in the right lobe of the liver. (b) CT scan shows multifocal ill-defined cystic lesions and several nodules (arrow) in the omentum on the right side of the abdomen. These appearances are suggestive of multilobulate parasitic abscesses in the liver with peritoneal seeding of parasitic granulomas. Biopsy of the liver and omentum demonstrated paragonimiasis.

 

Figure 12A
View larger version (107K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 12a.  Omental infarction in a 47-year-old man with abdominal pain. Axial (a) and sagittal (b) CT scans show localized fatty infiltration and congestion with a secondary mass (arrow) in the right lower aspect of the anterior abdomen. This appearance most likely indicates an omental infarction.

 

Figure 12B
View larger version (159K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 12b.  Omental infarction in a 47-year-old man with abdominal pain. Axial (a) and sagittal (b) CT scans show localized fatty infiltration and congestion with a secondary mass (arrow) in the right lower aspect of the anterior abdomen. This appearance most likely indicates an omental infarction.

 

Figure 13
View larger version (119K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 13.  Foreign-body granuloma in a 39-year-old woman with a palpable mass for 10 years and abdominal pain for 1 week. Unenhanced CT scan shows a large, well-circumscribed mass with dense calcification in the anterior midabdomen, an appearance suggestive of a foreign-body granuloma or organizing hematoma. After injection of contrast material, the mass showed no enhancement. A foreign-body granuloma with surgical gauze was found at surgical excision. The patient had a history of cesarean section 10 years earlier.

 

Figure 14
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 14.  Ventral hernia in a 66-year-old woman with a palpable mass in the abdomen. Sagittal CT scan shows herniation of omental fat through a defect (arrow) in the anterior abdominal wall. Focal ill-defined lesions with increased attenuation (arrowheads) in the omental fat adjacent to the abdominal wall defect are suggestive of omental fat infarction secondary to vascular compromise.

 

Figure 15A
View larger version (122K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 15a.  Morgagni hernia in a 70-year-old woman with an abnormality at chest radiography. Axial (a), coronal (b), and sagittal (c) CT scans show focal upward displacement of the transverse colon and omental fat (arrows in b and c) in the right anterior cardiophrenic area, an appearance suggestive of a Morgagni hernia.

 

Figure 15B
View larger version (161K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 15b.  Morgagni hernia in a 70-year-old woman with an abnormality at chest radiography. Axial (a), coronal (b), and sagittal (c) CT scans show focal upward displacement of the transverse colon and omental fat (arrows in b and c) in the right anterior cardiophrenic area, an appearance suggestive of a Morgagni hernia.

 

Figure 15C
View larger version (137K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 15c.  Morgagni hernia in a 70-year-old woman with an abnormality at chest radiography. Axial (a), coronal (b), and sagittal (c) CT scans show focal upward displacement of the transverse colon and omental fat (arrows in b and c) in the right anterior cardiophrenic area, an appearance suggestive of a Morgagni hernia.

 

Figure 16A
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 16a.  Fluid collection in the lesser sac in a 36-year-old man 2 days after subtotal gastrectomy with gastrojejunostomy for stomach cancer. Axial (a) and coronal (b) CT scans show a collection of meglumine diatrizoate (Gastrografin; Bracco Diagnostics, Princeton, NJ) in the lesser sac (black arrow). This finding was suggestive of leakage (white arrow in b) from the anastomosis of the gastrojejunostomy; such leakage was visualized during an upper gastrointestinal study with meglumine diatrizoate 2 days later.

 

Figure 16B
View larger version (136K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 16b.  Fluid collection in the lesser sac in a 36-year-old man 2 days after subtotal gastrectomy with gastrojejunostomy for stomach cancer. Axial (a) and coronal (b) CT scans show a collection of meglumine diatrizoate (Gastrografin; Bracco Diagnostics, Princeton, NJ) in the lesser sac (black arrow). This finding was suggestive of leakage (white arrow in b) from the anastomosis of the gastrojejunostomy; such leakage was visualized during an upper gastrointestinal study with meglumine diatrizoate 2 days later.

 

Figure 17A
View larger version (137K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 17a.  Inflammatory infiltrate in the lesser sac in a 68-year-old man with a history of heavy alcohol use who had epigastric pain for 2 days. CT scans show infiltration of peripancreatic fat (a) and spread of an inflammatory exudate to the lesser sac (arrow in b) and retroperitoneal space, findings suggestive of acute pancreatitis.

 

Figure 17B
View larger version (146K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 17b.  Inflammatory infiltrate in the lesser sac in a 68-year-old man with a history of heavy alcohol use who had epigastric pain for 2 days. CT scans show infiltration of peripancreatic fat (a) and spread of an inflammatory exudate to the lesser sac (arrow in b) and retroperitoneal space, findings suggestive of acute pancreatitis.

 

Figure 18
View larger version (127K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 18.  Lesser sac hematoma 1 day after abdominal blunt trauma in a 40-year-old man with acute abdominal pain. Contrast-enhanced CT scan shows a large acute hematoma in the lesser sac between the stomach and pancreas. Emergent laparotomy with hematoma evacuation and "bleeder" ligation was performed.

 

Figure 19A
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 19a.  Pancreatic pseudocysts in a 31-year-old man who had acute pancreatitis 3 weeks earlier. Axial (a) and coronal (b) CT scans show multiple cystic lesions in the lesser sac (arrow) and left subphrenic space, an appearance suggestive of pancreatic pseudocysts.

 

Figure 19B
View larger version (144K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 19b.  Pancreatic pseudocysts in a 31-year-old man who had acute pancreatitis 3 weeks earlier. Axial (a) and coronal (b) CT scans show multiple cystic lesions in the lesser sac (arrow) and left subphrenic space, an appearance suggestive of pancreatic pseudocysts.

 

Figure 20
View larger version (128K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 20.  Lymph node metastasis in a 46-year-old woman with an increased tumor marker level. CT scan shows a small nodular lesion (arrow) in the lesser omentum. The radiologic impression was metastatic lymphadenopathy. Early gastric cancer was detected at endoscopy, and a perigastric lymph node metastasis was confirmed at surgery.

 

Figure 21
View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 21.  Gastrointestinal stromal tumor in a 43-year-old woman with abdominal discomfort for 2 months. CT scan shows a well-circumscribed heterogeneous mass between the left lobe of the liver, stomach, and pancreas. The differential diagnosis included an exophytic hepatic neoplasm, a gastric submucosal tumor, and a primary neoplasm of the lesser omentum. At surgery, the patient was found to have a malignant gastrointestinal stromal tumor that originated from the stomach.

 

Figure 22A
View larger version (117K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 22a.  Cystic lymphangioma in a 48-year-old woman with abdominal discomfort. Axial (a) and coronal (b) CT scans show a large multiloculated cystic mass in the lesser sac. The attenuation of the lesion was about 16 HU (range, –14 to 40 HU) on unenhanced scans. The diagnosis of cystic lymphangioma was confirmed at surgical excision.

 

Figure 22B
View larger version (135K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 22b.  Cystic lymphangioma in a 48-year-old woman with abdominal discomfort. Axial (a) and coronal (b) CT scans show a large multiloculated cystic mass in the lesser sac. The attenuation of the lesion was about 16 HU (range, –14 to 40 HU) on unenhanced scans. The diagnosis of cystic lymphangioma was confirmed at surgical excision.

 




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
RADIOGRAPHICS RADIOLOGY RSNA JOURNALS ONLINE
Copyright © 2007 by the Radiological Society of North America.