398 AJR:195, August 2010 cavity by the dorsal and ventral mesogastri- um. Growth of the peritoneum and clockwise rotation of the stomach lead to the develop- ment of the perigastric ligaments (Fig. 1). The ventral mesogastrium attaches the fore- gut to the anterior abdominal wall and the diaphragm and forms the gastrohepatic and hepatoduodenal ligaments. The dorsal meso- gastrium fuses with the posterior abdominal wall and forms the splenorenal and gastrocol- ic ligaments. The remaining dorsal mesogas- trium evaginates to create the omental bursa. The caudal recess of the bursa fuses with the transverse colon to form the gastrocolic liga- ment and the greater omentum [6] (Fig. 2). Anatomy Disease processes commonly spread ei- ther transperitoneally or subperitoneally. In transperitoneal spread, disease commonly penetrates through the peritoneal layer and disseminates into the peritoneal cavity. Sub- peritoneal spread occurs when disease pro- cesses spread along the subperitoneal space of the peritoneal ligaments between the two layers of the peritoneum. The subperitone- al space is a large, interconnecting potential space that extends from the retroperitoneum into the peritoneal cavity. It thus represents a significant conduit for the spread of disease within the peritoneal cavity [7]. Gastric Cancer: Patterns of Disease Spread via the Perigastric Ligaments Shown by CT Cher Heng Tan 1 Silanath Peungjesada 2 Chusilp Charnsangavej 3 Priya Bhosale 3 Tan CH, Peungjesada S, Charnsangavej C, Bhosale P 1 Department of Body Imaging, University of Texas M. D. Anderson Cancer Center, Houston, TX. 2 Department of Radiology Services, VA North Texas Health Care System, Dallas, TX. 3 Department of Diagnostic Radiology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Box 368, Houston, TX 77030. Address correspon- dence to P. Bhosale (priya.bhosale@di.mdacc.tmc.edu). Gastrointestinal฀Imaging฀•฀Pictorial฀Essay CME This article is available for CME credit. See www.arrs.org for more information. AJR 2010; 195:398–404 0361–803X/10/1952–398 © American Roentgen Ray Society B etween 2001 and 2005, the age- adjusted incidence rate of inva- sive gastric cancer in the United States was estimated to be rela- tively low, at 8.0 per 100,000 men and women per year [1]. Nevertheless, this cancer takes a sizeable toll, with an overall 5-year survival rate estimated to be approximately 25% de- spite advances in surgical and staging tech- niques [1]. One of the reasons for this poor survival rate is the fact that gastric cancers tend to present late in the course of disease. The assessment of direct transmural and ex- traserosal spread of disease (T staging) and nodal involvement (N staging) has improved markedly with the advent of 3D MDCT with its excellent spatial and temporal resolution and its ability for multiplanar image reconstruction [2]. Because the depth of wall invasion, wheth- er there is nodal involvement, and whether there are distant metastases are major factors that in- fluence disease prognosis [3], CT has become a desirable preoperative imaging technique in this population [4, 5]. The presence of transmural extension with peritoneal spread has important implications for treatment because neoadjuvant chemotherapy is feasible for such cases [5]. Embryology The stomach is a derivative of the primi- tive foregut. It is suspended in the peritoneal Keywords: anatomy, CT, gastric cancer, ligaments, oncologic imaging DOI:10.2214/AJR.09.3070 Received May 19, 2009; accepted after revision November 11, 2009. OBJECTIVE. The stomach is suspended in the abdominal cavity by perigastric liga- ments, which are derived from the dorsal and ventral mesogastrium. These ligaments provide a direct contiguous pathway for the peritoneal spread of gastric cancer. In this article, we dis- cuss the embryology and anatomy of the stomach and describe the specific ligamentous routes along which gastric cancers may spread by direct invasion. CONCLUSION. Extragastric disease alters the prognosis and treatment options avail- able to patients with gastric cancer. Familiarity with the stomach’s embryology will help the radiologist understand its anatomy and, therefore, the patterns of regional spread of gastric cancer. The location of the primary tumor can predict involvement of specific perigastric liga- ments because locoregional spread of gastric cancer occurs along the arteries, veins, nerves, and lymphatic channels within those ligaments. Thus, identifying the location of the primary tumor can potentially improve patient outcomes. Tan et al. CT of Gastric Cancer Gastrointestinal Imaging Pictorial Essay Downloaded from www.ajronline.org by 52.73.204.196 on 05/18/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved