Special Regional Edition Asia-Pacific
September 2004

Virtual endoscopy detects, characterizes gastric cancer

3D MSCT stages preoperative gastric and extragastric lesions at no additional time or cost

By: H.A. Abella

Volume gastric imaging with multislice CT, or "virtual endoscopy," helps find and characterize gastric cancer and should also be used for preoperative staging of these malignancies, according to several studies presented at the 2003 RSNA meeting.

Until recently, only a few studies had described 3D gastric imaging using spiral CT. None had addressed the role that volumetric visualization with MSCT could play in the diagnosis of gastric cancer.

Two studies from South Korea found that 3D MSCT had an average detection rate of 95%, compared with 85% for 2D imaging. T-staging was more accurate with 3D imaging, while no statistically significant difference was seen for N-staging, said Dr. Jung Hoon Kim, a radiologist at Soonchunhyang University Hospital in Seoul. His group studied 106 patients.

Dr. Eung Young Ko, a radiologist at Hallym University Hospital in Seoul, and colleagues reported that virtual endoscopy detected advanced and early gastric cancer better than 2D imaging. They evaluated 162 patients.

According to Kim, virtual endoscopy also plays a role in the diagnostic workup of other diseases affecting the gastric tube, including lymphoma and gastric submucosal tumors.

Dr. Seishi Kumano, a radiologist at Osaka University Graduate School of Medicine in Japan, and colleagues used MSCT gastroscopy to study 41 patients. The technique accurately assessed serosal invasion in gastric cancer. Furthermore, it did not require additional time or cost compared with the standard technique. Kumano recommended its use for staging all cases of gastric cancer.

Virtual endoscopy has some limitations when compared with standard endoscopy. It cannot detect color changes in the gastric mucosa, nor can it stain the mucosa. It cannot evaluate tumor-related gastric wall motion, as in type IV advanced gastric cancer. But 3D MSCT gastroscopy is easier on patients, who otherwise would undergo an invasive procedure, and it can evaluate both gastric and extragastric lesions, Kim said.

"The value of 3D in gastric cancer is open for discussion," Dr. Borut Marincek, radiology chair at University Hospital Zurich in Switzerland, told Diagnostic Imaging. "While this condition is more prevalent in the Far East, particularly in Japan, than in Europe or the U.S., the accumulation of data could have implications for patients affected by the disease all over the world."