CT Features Of Gastrointestinal Stromal Tumors And Their Correlation With Malignant Risk

Objective:To analyze the CT features of gastrointestinal stromal tumors(GISTS)and evaluate their values in malignant risk prediction.Methods:The medical records of 35 patients with pathologically and immunohistochemically proven GISTS by surgery or biopsy at our institution were reviewed. Two radiologists retrospectively reviewed the CT findings, and the final interpretations were reached by consensus. The site, size, contour, border, growth pattern, necrosis, enhancement pattern, degree of enhancement, calcification, abdominal lymph nodes, ascite, bowl obstruction, direct invasion and metastasis of the tumors were analyzed.Single variable analysis and multivariate stepwise Logistic regre-ssion were employed to reveal independent variable X(various CT c-haracteristics) in predicting the dependent variable Y(benign, low po-tential malignant and malignant). First of all, the single variable ana-lysis was performed and the independent variables which had the st-atistical significance entered the further multivariate Logistic regressi- on analysis(the backward stepwise regression method, Logistic multi-variate stepwise regression analysis).The correlation between tumor c-haracteristics used Spearman rank correlation analysis, P <0.05 was r-egarded statistically significant.Results: The tumors were originated from the gastric wall(17 cases), small intestine(9 cases), peritoneum(5 cases) and rectum(2 cases) respectively, and 2 cases could not confirm their origin due to their big sizes and widely nearby infiltration. Pathology certified the benign(7 cases), malignant (17 cases) and low malignant potential (11 cases). The size of tumors ranged 2-5cm (benign), 6-25cm(malignant) and 5.6-10cm (low malignant potential). The contour of benign tumors were round or oval and the malignant tumors gave us the lobulated appearances, clear borders were shown in 33 cases. Growth patterns were the extraluminal(19 cases) and mixed(8 cases). 26 cases showed different degrees of intratumorous necrosis with heterogeneous enhancement, intermediate enhancement was found in 23 cases.Univariate analysis showed tumors'size, contour, growth pattern, necrosis, enhancement pattern and degree of enhancement showed significantly relative to tumors'malignant risk(P<0.05). Only tumors'size displayed the statistical significance when used the multivariate stepwise logistic regression analysis(P=0.033).Conclusion:(1)GISTS a clear boundary, mainly to the growth of cavity, there are different degrees of necrosis and non-uniform delayed enhancement, no lymph node swelling and metastasis and so on. (2) through the CT features of the tumor size (>10cm) can predict gastrointestinal stromal tumor of malignant risk, to provide valuable clinical information.