| Objective:1. To evaluate the diagnosis of multislice spiral CT in gastrointestinal stromal tumors, and to find the enhancement features of dynamic enhanced MSCT scanning in GIST tumor.2. To evaluate multislice the MPR and CPR techniques of spiral CT on positioning diagnosis of GIST.3. To investigate the relationship of tumor size with necrotic and calcification of GIST.4. Improve the diagnosis and differential diagnosis of GIST for the clinical classification of the tumor, to provide reference information of significant value for treatment plan.Materials and Methods:Collection of the South Hospital from January 2005 to November 2009 period 35 cases of pathologically confirmed GIST, including 14 cases of stomach, small intestine in 9 cases, colon in 2 cases,4 cases of retroperitoneal, abdominal and pelvic 6 cases(parenteral),19 cases were male,16 female, aged 26 to 77 years, average age is 55.88 years. The group of 35 patients showed 21 cases of upper abdominal discomfort, abdominal mass in 7 cases,6 cases of upper gastrointestinal bleeding, blood in the stool in 5 cases, physical examination occasionally found in 3 cases.35 cases were CD34 and/or CD117 expression. The group of 35 cases was confirmed by surgery, routine pathology and immunohistochemistry confirmed 32 cases of spindle cell tumors,2 cases of necrosis, and spindle cell tumor, one case of spindle mesenchymal tumor. There have no low malignant potential, low malignant potential in 8 cases, moderate in 8 cases of malignant potential,19 cases of highly malignant potential. CD117-positive 35 cases; CD34 positive in 25 cases, negative in 10 cases; vimentin (Vim) positive in 31 cases,4 cases were negative.By GE Light Speed 16 slice CT, using 16×1.25 mm detector mode, pitch 1.375, collimation and pitch of 7.5 mm; All patients underwent plain and dynamic enhanced computed tomography, patients have to fast before the examination, ban water and cleaning enema, orally 30 min before scanning by 1.5%to 2%diatrizoate 800-1000 ml, so that gastrointestinal filling. Patients were supine position, scanning area from the diaphragm to the pubic symphysis level, first scan and then do three dynamic enhanced CT scans. Forearm vein by using high-pressure syringe to 3.0 ml/s injection of contrast agent iohexol (300mgI/ml) 70～100 ml.3 Dynamic enhancement after contrast injection, respectively,25～30s (arterial phase),60-70s (venous phase), 120～180s (late phase) started scanning, and to 1.25 mm thickness of the image reconstruction, will be the original data into ADW 4.2 workstation reconstruction, line MPR (multiple planar reconstruction) and CPR (curved planar reformation) after treatment of tumors and the relationship between the digestive tract wall. Statistics of all cases by the general situation of the lesion site, size, growth pattern, shape, density, edge, ulcers, strengthen the characteristics of invading into adjacent tissues and organs and the presence of metastasis were analyzed, and results were compared with pathologic study.Results:33 cases of single cases,14 cases of gastric (40%), which occurred in 2 cases of gastric antrum, body of stomach lesser curvature in 1 case,1 case of posterior gastric wall, gastric 4; small intestine in 9 cases (25%), which occurred in ileocecal 1 case,1 case of the jejunum, duodenum in 5 cases, the other two cases of intestinal lesions and intestinal lumen connected to the cavity inside or outside and inside; 4 cases of retroperitoneal (11%),2 cases frequently occurring case of multiple abdominal and pelvic placeholder. Maximum lesion diameter 2.5～22cm,<5 cm in 8 cases (22.9%),≥5 cm in 27 cases (77.1%). 13 cases were regular in shape of round shapes, and border more clearly; 22 cases showed more irregular, lobulated, and the unclear boundaries and adjacent structures or edge blur. In this group of 35 patients with GIST in the cavity type in 12 cases,10 cases of extraluminal, intramural type 2 cases,11 cases of gastrointestinal appearance. Plain uniform density in patients with 12 patients,23 patients uneven, enhanced scanning in all cases are different degrees of enhancement, which significantly enhanced in 17 cases,18 cases of obvious strengthening; homogeneous enhancement in 13 cases, inhomogeneous enhancement 22 cases,6 cases with arterial phase enhancement was the most significantly higher than the venous phase enhanced arterial phase, and delayed phase enhanced also slightly higher than the portal venous phase, plain and arterial enhancement scan three statistical difference between significance (F= 42.049, P= 0.001), in addition to portal venous phase and delayed phase showed no significant difference between, the rest of the differences were statistically significant between.26 cases of low-density cystic tumor center, tumor calcification in three cases of simple, low-density cystic calcification combined in 3 cases, cystic degeneration and hemorrhage,1 case of cystic tumor necrosis and tumor size was positively correlated (r=0.629,P<0.001); liver transfer within the 5 cases, liver and pelvic metastasis in 1 case,2 cases of peritoneal metastasis, lymph nodes in 3 cases (2 cases lesions were pathologically confirmed inflammatory changes,1 case was pathologically confirmed as metastasis). Around the violations occurred in 11 cases, mainly lesions and organ boundaries are violated unclear, vague or disappear fat space, violations can occur locally, unusual organ. Enhanced scanning process in the abnormal artery in 2 cases.Conclusion:1. Multislice spiral CT of gastrointestinal stromal tumor has a high diagnostic value, GIST CT scan in the often isolated in the class round, oval or irregular-shaped class of soft tissue density mass. Cystic tumor of the body prone to tumor necrosis or hemorrhage Ershi uneven density, part of the mass seen in the dot sheets calcification. The larger volume of tumor more vulnerable to necrotic. If cystic necrosis, calcification, hemorrhage more common in malignant stromal tumors.2. Dynamic enhanced multi-slice CT scan three different mass can be enhanced by way of their degree of enhancement is also a difference, but most of the mass in the vein of strengthening significantly higher than the arterial phase, and the delay is also slightly higher than that of strengthening portal phase. Thus, MSCT three dynamic enhanced MRI in the preoperative favorable location and GIST diagnosis and differential diagnosis.3. Gastrointestinal stromal tumor of the CT manifestations with histopathologic very closely, multi-slice CT to determine the tumor and the relationship with the surrounding tissues and organs, with or without metastasis, etc. have some value, but in determining tumor of benign and malignant still a limit, currently only based on CT diagnosis of tumor size and the internal availability of cystic degeneration, necrosis and signs of bleeding to determine the benign or malignant, diagnosis relies on pathology, immunohistochemistry and electron microscopy.4. Through the thin slice spiral CT reconstruction, the station obtained from the reconstructed images (MPR and CPR) can be rotated to different angles from the detailed observations on the lesions, can clearly show lesion in shape, size, internal structure, growth characteristics and lesion and surrounding tissues and organs of the relationship, can significantly improve the diagnostic accuracy of lesion localization, clinical grade of the tumor, a treatment plan to provide significant value reference information.5. Multislice spiral CT scan a wide range of scanning speed, inspection time is short, high spatial resolution and high resolution, image quality, is a noninvasive, simple and advanced inspection technology, in gastrointestinal cancer presurgical evaluation, diagnosis has a good prospect.
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