sarcoma.

GIST is a visceral sarcoma that arises from the gastrointestinal tract. The clinical features and radiologic differential diagnosis of gastrointestinal stromal tumours are discussed. Gastrointestinal stromal tumours is a rare gastrointestinal tumour. Computed tomography (CT) is an imaging modality of choice for diagnosing GIST. The aim of this Retrospective study is to evaluate CT feature of GIST in20 cases. In this study 20 biopsy proven cases of GIST were evaluated retrospectively in our department from November 2010 to July 2012. The CT scan was performed prior to the treatment in all these patients. CT imaging feature includes, tumour location, size/diameter, degree & pattern of enhancement, intraluminal/exophytic, internal necrosis & haemorrhage, perilesional rat stranding, local spread, nodal & distant metastasis. Out of 20 patients, in 13/20 (65 %) cases tumour was found in stomach, 4/20 (20%) in small bowel (jejunum & ileum), 2/20 (10%) in omentum and mesentery; and 1 (5%) case tumour was found in transverse colon. 14/20 (70%) had exophytic tumour with communicating to lumen of gastrointestinal tract or in omentum and mesentery; rest 6/20 (30%) had polypoidal mass. Size of tumour ranges from 4 to 15 cm, with mean of 7.9 cm.15/20 (75%) cases shows heterogeneous enhancement with necrosis and/or calcification, rest 5/20 (25%) had homogenous enhancement. The CT HU ranges from 35 to 55, with mean of 40, 14/20 (75 %) cases had well defined margins of tumour, and rest 6 (30%) cases showed perilesional fat stranding and loss of fat plane with adjacent organ.2/20 (10%) cases showed regional nodal involvement and 3/20 (15%) cases shows distant metastasis to liver(2) & lungs (1). Keywords: Gastrointestinal stromal tumour, GIST, Computed tomography, sarcoma.