1Department of Internal Medicine, Institute of Gastroenterology Tokyo Womens' Medical College, 2School of Science and Engineering, Waseda University
Low gray-level areas, Density of gastric cancer cell
We studied the tissue characterization of gastric cancer echoes, with attention to the low gray-level
areas. We investigated low gray-level areas in gastric cancer echoes and supposed the low gray-level of
gastric cancer echoes to reflect masses of gastric cancer cells, judging the homogenous low-echo area in
the medullary type of gastric cancer echo. We selected three-seven regions of interest (ROI, 10×10
pixeles) on gastric cancer echo in each case, and we calculated the percentage of low gray-level pixels in
the ROI (P(LGL)). The low gray level was determined to be under 45/256 in cases of medullary and
intermediate cancer, and was determined to be under 65/256 in cases of gastric cancer cases with fibrosis.
We evaluated percentage of low gray level pixels on ROI in each case by variance analysis. On the other
hand, we calculated density of gastric cancer cells of resected specimens under high magnification. As a
result, P (LGL) was related to density of gastric cancer cells in each case. We concluded that low echo
areas of gastric cancer echo reflected masses of gastric cancer cells. This method might be useful for
diagnosing the depth invasion of gastric cancer with fibrosis.