MR扩散加权成像在胃良恶性肿瘤鉴别诊断中的应用价值

Application of Diffusion Weighted Imaging in Differential Diagnosis of Benign and Malignant of Stomach Neoplasm

目的探讨扩散加权成像(diffusion-weighted imaging,DWI)及其表观扩散系数(apparent diffusion coeffi-cient,ADC)在胃良、恶性肿瘤鉴别中的价值,确定ADC值在良恶性肿瘤鉴别中的最佳临界点。方法 39例经手术或胃镜活检病理证实的胃肿瘤性病变患者,进行常规MRI及DWI,b值采用800 s/mm2,以病理结果为金标准,统计分析胃良性和恶性占位之间的ADC值差异。结果当b值为800 s/mm2,良性组ADC平均值为(2.200±0.959)×10-3mm2/s,恶性组ADC平均值为(1.89±0.463)×10-3mm2/s,两组间有显著差异(F=25.12,P<0.05)。受试者工作特征(ROC)曲线显示,区别良恶性胃部肿瘤的最佳临界点为1.915×10-3mm2/s,其敏感性为88.7%,特异性为91.1%,约登指数为0.798。结论 DWI在胃肿瘤诊断中具有可行性。b值为800 s/mm2时,胃良性和恶性肿瘤之间的ADC值存在显著统计学差异,区别胃部良恶性肿瘤的最佳临界点为1.915×10-3mm2/s,ADC值对于鉴别胃良恶性肿瘤有辅助诊断价值。

Objective To determine the diagnostic value of Diffusion Weighted imaging（DWI） in differential diagnosis of begin and malignant of gastric neoplasm. Methods 49 cases with gastric neoplasm proved by operation pathologic re- sults were reviewed. 49 Cases were divided two groups ：the first group included 34 cases of malignant lesions and 15 cases of benign lesions, b value of 800 s/ram2 was used, ADC value of begin mass and malignant were compared. Results As b value were 800 s/mm2, ADC of begin mass and malignant mass were （2.200±0.959）×10^-3mm2/s,（1.89±0.463）×10^-3mm2/s respectively （F = 25.12, P 〈 0. 05 ）. The ROC curve showed that the optimal critical point of the distinction between benign and malignant stomach tumor was 1. 915 × 10^-3 mm2/s, which sensitivity and specificity were 88.7%, 91.1%, Youden index was 0.798. Conclusion Diffusion weighted imaging is feasible in diagnosis of gastric neoplasm, as b value is 800 s/mm2, ADC values of begin mass and malignant mass are significant different. ADC value could provide additional information in distinguishing benign and malignant gastric neoplasm.