THE ROLE OF MULTIDETECTOR COMPUTED TOMOGRAPHY IN THE EVALUATION OF GASTRIC MALIGNANCY

Abstract

Diseases of the stomach and duodenum are immensely common, accounting for 4% of family doctor visits per year and account for about 50% of cases of dyspepsia. Gastric carcinoma represents the most common gastric neoplasm accounting for 95% of all gastric tumors. Prognosis and therapy of gastric carcinoma depend on the stage of the disease at the time of the diagnosis and the first challenge for clinicians is to define the extent of the tumor in order to plan the best treatment Besides, an early diagnosis and accurate staging are crucial for the choice of an accurate therapeutic approach and can also influence the survival rate. Endoscopy and double contrast barium examination of the upper gastrointestinal tract are still the basic investigational tool for diagnosing gastric malignancies, but they are stressful and uncomfort¬able for patients. Also, they are exclusively based on depiction of the gastric mucosa and are limited by their inability to evaluate transmural and extragastric exten¬sion of disease. This means that they are unsuitable for T as well as M-staging according to the TNM system. The depth of mural invasion and the presence of extragastric lesions can be determined with endoscopic ultrasonography (US) and computed tomography (CT) which are often used as preoperative image modalities in staging gastric malignancies. EUS was superior to CT in T staging and perigastric lymph node evaluation in previous studies. However, it cannot be used for metasatatic staging (peritoneal dissemination and liver metastasis) due to diminution of the field of view. Recently, fast scanning with rapid infu¬sion of IV contrast medium administration (dynamic CT) and filling the stomach with a large amount of low-density fluid have been used to overcome the limitations of conventional CT in the evaluation of the transmural and extraserosal spread of disease with rates of high accuracy rates.