胃肠道间质瘤的多层螺旋CT诊断价值分析

目的探讨胃肠道间质瘤的MSCT表现及诊断价值。方法回顾性分析经免疫组化证实的16例胃肠道间质瘤MSCT资料，4例术后随访7～36月。结果本组肿瘤源于胃10例，小肠5例，肠系膜1例。肿瘤平均最大径9．94cm±7．75cm，其中良性5例，直径不超过5cm，形态规则，强化轻而均匀。交界性5例，其MSCT不具特征。恶性6例，多呈分叶及多囊实性改变，不均匀显著强化，动脉期见结节或条带状显著强化，侵犯周边及远处转移。MSCT定位、定性准确性分别为87．5％（14／16）、68．8％（11／16），对恶性的阳性预测值为85．7％（6／7）。6例动态增强5min延时期肿瘤均见中度强化，5例分化不同的胃间质瘤三期动态强化曲线有差别。4例随访发现3例有术后转移。结论MSCT多平面重建及动态增强更能显示胃肠道间质瘤的特征表现，对其定位、定性诊断及术后随访具有重要价值。

Analysis on the value of multislice spiral CT in diagnosing the gastrointestinal stromal tumor

Objective To investigate the imaging features and diagnostic value of multi-slice spiral CT （MSCT）for gastrointestinal stromal tumors （GIST）.nethods MSCT findings in 16 cases with immunohistochemically proven GIST were retrospectively analyzed. 4 cases were followed-up by MSCT from 7 to 36 months .Results The primary tumors originated from the stomach（n=10）, small bowel（n=5） and mesenterium（n=l）. Mean primary tumor size was 9.94 cm±7.75. The 5 cases of benign GIST were less than 5 cm and gently enhanced with regular contour in MSCT . There were not features of MSCT in the 5 borderline GIST. The MSCT characteristic appearances of 6 malignant GIST were as following ： lobulated contour and multilocular cysts were commonly seen . Tumors were usually heterogeneously enhanced markedly. Especially in arterial phase,the striking enhanced nodule or strip appearance were often displayed,with invasion of adjacent tissues and distant metastasis.The accuracy rates of localized diagnosis and qualitative diagnosis of GIST by MSCT were 87.5% （14/16） and 68.8% （11/16）,respectively. Positive predictive value in diagnosing malignant GIST by MSCT was 85.7%（6/7）. There were midrange enhancement in 6 cases during the 5 minutes delay phase.Each dynamic enhancement curve of 5 gastral stromal tumors was different. The recurrence or distant metastasis of tumors was found in 3 cases followed-up by MSCT. Conclusion Multi-phase enhanced MSCT with the muhiplanar reconstruction can clearly show the characteristic appearances of GIST.It plays an important role to display the location and evaluate the prognosis of GIST