CT值变化率在胃肠道间质瘤靶向治疗影像学评效的应用研究

目的探讨CT值变化率在伊马替尼治疗胃肠道间质瘤（Oastrolntestinal Stromal Tumor．GIST）CT早期疗效评价的应用价值，探索结合长径及CT值变化率后的Choi标准在临床适用范围。方法回顾分析2003年4月至2008年1月，我院175例伊马替尼治疗复发转移性GISL息者，其中26例有中短期（2～6个月）连续GT复查者纳入研究。轴位图像测量肿瘤最长径线及最大层面静脉期强化CT值，按照Choi标准要求（≤5灶／脏器，≤10灶／例）累加并平均得到病例长径及CT值均值。计算治疗前后长径及GT值变化率。全部病例根据Choi标准划分为有缓解组（Good Eesponses，Goodg）和无缓解组（Poorgesponses，FoorR）。Kaplan—Meier法比较结合及未结合CT值标准（降低≥15％）对评价肿瘤疗效的差异，评价Choi标准在短期治疗过程中复查病例的应用情况。结果根据Choi标准评价治疗缓解19例，无缓解7例，缓解率73％。中位随访时间为23．5个月，截至2008年1月26例患者的中位肿瘤进展时间（Time to Tumor Progression，TTP）为17.5个月。本组5例出现长径结合CT值变化率后评价为缓解的情况。仅根据长径退缩率≥10％分组得到的TTP异无统计学意义（P〉0．05），结合CT值降低率≥15％标准后，分组TTP出现差异（P〈0.01）。首次（基线）CT检查在服药后2个月内患者，应用Choi标准评价缓解和无缓解组间TTP差异有统计学意K（P〈0.05）。结论联合CT值变化率与长径退缩率作为指标，可在早期有效评价GIST伊马替尼治疗疗效，更为客观的反映中长期预后。

Study of CT Attenuation Value in the Use of Early Evaluation of Imatinib in Treatment of Gastrointestinal Stromal Tumor

Objective To investigate the decrease rate of CT attenuation value in the early evaluation of gastrointestinal stromal tumor （GIST） treated by imatinib, and to explore the clinical use range of Choi criteria which combined the lengthdiameter retraction and CT attenuation value decrease rate. Methods Retrospectively analysis 175 cases of GIST treated by imatinib during Apr 2003 to Jan 2008, among which 26 cases had nediumm-short term （2-6months） CT follow-ups enrolled in the study. The length-diameter was measured on axial images, and CT attenuation coefficient （HU） of tumors was measured by drawing ROIs around the margin of entire tumor. The sum of leogth-diameter and mean HU of selected lesions in each pafient was computed according to Choi criteria （≤5/organ, ≤10/case）. The decrease rate of length-diameter and tumor HU was computed. All of the patients were divided into two groups （goed responder, GoodR and poor responder, PoorR） according to Choi criteria. Kaplan-Meier test was employed to evaluate the CT attenuation value in the use of therapeutic effect evaluation. The use of Choi criteria in short-term treatment reexamination was also evaluated. Rosults Theaewere 19 cases of GoodR and 7 cases of PoorR by Choi criteria, and the response rate was 73%. Median follow-up was 23.5 months Median time to tumor progression （ITP） was 17.5 months up to January 2008. Five cases were evaluated as good responder after combined with the CT value change rate. No statistical difference of TTP appeared baween two groups only by retraction rate ≥10% of lengthdiameter （P〉0.05） which displayed signifcance after combined with the decrease rate ≥15% of HU （P〈0.01）. There was statistical significance of TIP between GoodR and PoorR groups divided by Choi criteria among the patients whose baseline CT examinations were performed shortly after （〈2months） imatinib administration （P〈0.05）.Conclusion The new criteria combined the decrease rate of CT attenuation value with retraction rate of length-diameter can be used in early evaluation of GIST treated by imafinib, which can predict the mid-long term prognosis more objectively.