CT finding and diagnosis of gastrointestinal sromal tumor

Objective: To explore imaging features of gastrointestinal stromal tumor(GIST). Methods: CT findings were retrospectively analyzed in 26 cases with surgically and pathologically proved GIST. Results: Among the 26 cases, 17 masses were located in stomach, 7 in small intestine and 2 in rectum. On non-contrast enhanced CT scan, the density of masses is equal to that of soft-tissue. The lesions were homogenous in 8 cases; hypo-dense necrosis was found within the lesions in ]8 cases; calcification was revealed in 5 cases; and well demarcated lesions were demonstrated in 19 cases. In contrast enhanced scan, remarkable enhancement was seen in the parenchyma of the tumor, CT value increased from 20-60 HU, while no enhancement was revealed in the necrosis and cystic area of the tumor. Five cases out of 26 had been diagnosed as benign GIST, while malignant GIST was determined in the other 21 cases. CD34 antibody was positive in all 26 cases. Depending on the pathological findings, the CT manifestations of tumors may be classified as substantial lesions, lesions with small necrosis and lesions with large necrosis and cystic change. Conclusion: There are characteristic CT manifestations of GIST, helpful in determining the pathological nature of the GIST and the prognosis. (authors)