Tu1159 Clinical Outcome of Type 1 Gastric Carcinoid With Endoscopic Management—Multi-Center Study in Japan

one patient, the mass lesion was not related to bowel wall and surgical resection confirmed its omental origin.On CT the pre contrast average density of these tumors was 37 HU (range 20-58 HU).Calcifications were unusual and found in only 8 %.All tumors showed significant enhancement on post contrast CT (average of 31 HU (range 10-99)).35% of the tumors (n=9) showed homogeneous enhancement and the rest enhanced heterogeneously (n=17).Areas of necrosis were seen in almost one third of the cases (n=8, 31% of the tumors).Presence of metastases was associated with larger primary tumor size (mean: 13.2cm (95% CI: 7.3-19.3))when compared to non metastatic tumors (mean: 5.1 cm (95% CI: 3.7-6.4)).In addition, the presence of necrosis on CT scan was associated with increased risk of metastasis when compared to non necrotic tumors (75% vs. 5.6 %; p = 0.0002).Heterogeneous enhancement on post contrast CT was also associated with the presence of metastasis (41.2 % vs. 0%; p=0.02).There was no significant association between tumor location, patient age and degree of enhancement and the presence of metastasis (p value > 0.05).Using binary logistic regression, tumor necrosis remained statistically significant with p value of 0.013 (p<0.05).Nine patients underwent CT/PET at our department, 7 of them showed GIST tumors as a focal area of increased metabolism with SUV values range from 2.5-7.Three tumors were metabolically relatively inactive with SUV values less than 2.5.Conclusion: CT scan is a valuable tool in evaluation of patients with GIST by suggesting the diagnosis and predicting malignant behavior.Large size, the presence of necrosis and heterogeneous enhancement on CT were associated with metastasis.