Ritsuo Mouri

Evaluation and validation of computed virtual chromoendoscopy in early gastric cancer.

BACKGROUND The Flexible spectral Imaging Color Enhancement (FICE) system estimates the spectrum reflectance from a white-light endoscopic image and reconstitutes a color image from the wavelength, including useful information about the GI tract. The aim of this study was to investigate the usefulness of FICE with a specific wavelength in the assessment of early gastric cancers (EGCs), and the relationship between the FICE visualization and blood vessels. DESIGN A retrospective study. SETTING Department of Endoscopy, Hiroshima University, Hiroshima, Japan. PATIENTS AND MAIN OUTCOME MEASUREMENTS The study subjects consisted of 100 patients with EGCs (78 differentiated, 22 undifferentiated) who underwent an endoscopic or surgical resection. We analyzed the wavelengths to generate the maximum difference of the spectral reflectance between the normal gastric mucosa and the EGCs. We observed the same visual field first with white-light endoscopy and then with the FICE system. Then, we scored the demarcation of color between the cancer and the normal mucosa of white-light endoscopic observation and FICE observation, each without magnification. We examined the relationship between the score of the FICE image and the section of the vascular space. RESULTS The wavelength that generated the maximum difference in the tissue was 530 nm. The score of the FICE observation improved in 46 cases (46%), was unchanged in 54 cases (54%), and decreased in no cases (0%). There was a correlation between the score of the FICE images and the section of the vascular spaces. CONCLUSIONS The FICE observation demonstrated that setting the wavelength at 530 nm resulted in an improvement in the visualization of the EGCs. It is thought that the FICE system is noninvasive and may more easily detect EGC without dye during both routine and detailed examinations.

Usefulness of Endoscopic Ultrasonography in Determining the Depth of Invasion and Indication for Endoscopic Treatment of Early Gastric Cancer

Introduction Endoscopic ultrasonography (EUS) is a useful method for visualizing features of gastric cancer. However, a previously reported classification system tended to result in overstaging. We investigated the usefulness of EUS for evaluation of the depth of gastric cancer invasion and indications for endoscopic treatment. Methods Accuracy of EUS for determining the depth of invasion and incidences of a positive basal margin were assessed in 235 patients who underwent endoscopic treatment or surgery for gastric cancer. The EUS-determined depth of invasion was classified as follows: EUS-M (lesion confined to sonographic layers 1 and 2); EUS-M/SM border (lesion with changes in sonographic layer 3 but no deeper than 1 mm); EUS-SM (lesion with changes in sonographic layer 3 deeper than 1 mm); or EUS-AD (lesion with changes in sonographic layer 4 or 5). Results Accuracy of EUS for determining the depth of invasion was as follows: EUS-M, 99% were M and SM1 lesions; EUS-M/SM border, 87% were M and SM1 lesions; EUS-SM, 91% were SM2 lesions; EUS-AD, 100% were muscularis propria or deeper lesions. There was no EUS-M or EUS-M/SM border lesion for which endoscopic treatment resulted in a positive basal margin. Conclusions EUS is useful for accurately determining the depth of invasion of gastric cancer. When there are no endoscopically determined ulcerous changes, endoscopic treatment should be considered for EUS-M and EUS-M/SM border lesions, and EUS-SM lesions should be treated surgically.