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目的比较3.0 T MR单序列分次屏气与分序列单次屏气在胃癌扩散加权成像(diffusion weighted ima-ging,DWI)的信噪比(SNR)、对比噪声比(CNR)、表观扩散系数(ADC)值和伪影等方面的差异。资料与方法对经胃镜病理证实的18例胃癌患者行术前MR DWI检查,均行单序列分次屏气与分序列单次屏气两次扫描,比较两种检查方法的SNR、CNR、ADC值及伪影等影响图像质量的因素,以及胃癌与正常胃壁ADC值之间的差异。结果18例胃癌DWI图像上均显示为高信号,两种检查方法间正常胃壁及癌肿ADC测量差异无统计学意义(P>0.05),而单次屏气DWI的SNR、CNR明显高于分次屏气扫描,单次屏气胃腔内自由水以及背景噪声信号强度明显低于分次屏气扫描,差异均有统计学意义(P<0.05);单次屏气法DWI图像的呼吸运动及并行采集空间敏感性编码技术(ASSET)伪影明显减轻;胃癌ADC值与正常胃壁ADC值间比较差异有统计学意义(t=-10.167,P<0.001),胃癌组明显低于正常胃壁组ADC值。结论 3.0 T MR胃癌DWI中单次屏气图像质量明显优于分次屏气扫描,胃癌ADC值明显低于正常胃壁ADC值,具有很好的临床应用价值。
Objective To compare the SNR, CNR and apparent diffusion coefficients of 3.0 T MR single-sequence graded and fractionated breath-hold gas imaging in gastric cancer with diffusion weighted imaging (DWI) ADC) values and artifacts and other differences. Materials and Methods 18 cases of gastric cancer confirmed by gastroscopic pathology were performed preoperative MR DWI. Both single-slice and double-slice single breath-hold were scanned twice. SNR, CNR and ADC were compared between the two methods Artifacts and other factors affecting the image quality, as well as the difference between normal gastric ADC and gastric cancer. Results The DWI images of 18 cases of gastric cancer showed high signal intensity. There was no significant difference between the two methods in normal gastric wall and cancer ADC (P> 0.05), while SNR and CNR of DWI in single breath-hold were significantly higher than those in fractional (P <0.05). The intensity of breath motion and parallel acquisition of single-breath-hold DWI images were significantly higher than those of single breath-hold scanning ASSET artifacts were significantly reduced. The ADC value of gastric cancer was significantly different from that of normal gastric wall (t = -10.167, P <0.001). The gastric cancer group was significantly lower than that of normal gastric wall group. Conclusion The image quality of single breath-hold image in DWI 3.0T MR gastric cancer is better than that of single breath-hold scanning. The ADC value of gastric cancer is significantly lower than that of normal gastric wall, which has a good clinical value.