الفهرس 
Basic and radiological anatomy of the stomachOnly 14 pages are availabe for public view
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Abstract
The stomach is involved by a spectrum of benign and malignant neoplastic lesions. More than 95% of malignant tumors of the stomach are adenocarcinomas which can be classified macroscopically into early and advanced types, and microscopically into tubular, papillary, mucinous and signet ring types.
The clinical manifestations of gastric neoplasms vary from abdominal pain to vague symptoms such as weight loss and anemia. In most cases, Computerized Tomography (CT) is requested to better demonstrate a pathologic process seen or suggested clinically or by other diagnostic means such as upper gastrointestinal radiographic series or endoscopy.
Computed tomography (CT) has proved to be a valuable adjunct to endoscopy. CT clearly demonstrates the primary pathologic condition and shows the extension of the disease to adjacent or distant structures.
In this essay, the role of multidetector row spiral CT technique in staging of gastric adenocarcinoma has been discussed. Three dimensional imaging of the stomach using shaded surface display technique allows the detection and evaluation of the early gastric cancer which become brighter, and even endoscopic 3D CT of the stomach may provide an overview of the tumor mass within the lumen of the stomach as seen with gastroscopy. 3D CT of the stomach has some limitations as creating 3D CT reconstruction is time consuming (about 25-35 min/patient), and detecting flat and small lesions is difficult. Virtual endoscopy of the stomach is the most promising technique that allows visualization of the inner surface of the stomach simulating the view traditionally obtained by gastroscopy. All these techniques are presented together for better diagnosis of gastric neoplasms with special emphasis on CT signs and criteria for differentiation of each lesion.
The use of MPR images allows the radiologist to choose an optimal imaging plane to accurately evaluate the depth of tumor invasion of the gastric wall and to identify the thin fat plane between the tumor and adjacent organs.
MPR images can also provide more accurate measurement of lymph node size, and better differentiation between lymph nodes and small perigastric vessels is possible.
Virtual gastroscopy allows detection of subtle mucosal changes and differentiation of mucosal lesions from submucosal lesions in the same way as conventional gastroscopy. It provides additional information for evaluation of mucosal detail in the stomach.
Virtual gastroscopy has several advantages over gastroscopy: It has a wider field of view than conventional gastroscopy, and it has no blind point because retrospective reformation is available. Volume rendering provides global orientation of the focal findings in the stomach in the same way as conventional gastroscopy imaging. The referring physicians especially appreciate this orientation because it provides useful information for preoperative mapping.
Dynamic contrast-enhanced multi–detector row CT with MPRs acquired during the portal venous phase correctly depict the presence or absence of solid organ metastases.
Multidetector CT with MPR overcomes the limitations of two-dimensional axial CT, and virtual endoscopy provides images similar to conventional endoscopic images for the evaluation of EGC. Multidetector CT with MPR and virtual endoscopy is a promising noninvasive method for the early detection and accurate preoperative staging of EGC, which could lead to improved prognosis and are essential in planning optimal therapies, such as endoscopic mucosal resection or gastric resection. The early detection and accurate preoperative staging of EGC are very important because these patients may be ideal candidates for laparoscopic or minimally invasive surgery.
Gastric studies have enabled accurate diagnosis and staging of gastric adenocarcinoma. Better understanding of the need to optimize CT protocols suggests that the diagnostic value of CT in these applications will increase.
In spite of the increasing role of endoscopic ultrasound and magnetic resonance imaging in evaluating the stomach, CT will remain an important cost effective imaging tool in preoperative staging of gastric adenocarcinoma