mDIXON-MRA技术评价乳腺癌腋窝淋巴结-血管关系时不同扫描方案对图像质量的影响

The effect of different scanning schemes on the image quality in evaluating the relationship between axillary lymph nodes and blood vessels of breast cancer

目的应用mDIXON-MRA技术评价乳腺癌腋窝淋巴结与血管关系,探讨其中不同团注流速和延迟扫描时间对图像质量的影响。材料与方法2018年12月至2020年1月共77例临床已确诊的乳腺癌患者,术前均行腋窝区域的磁共振扩散序列及增强血管成像,随机分4组进行动态扫描,分别给予不同对比剂流速:1.5 mL/s、2.0 mL/s、2.5 mL/s、3.0 mL/s,经过图像后处理重建,由两位放射科医师分别对所得图像进行评估和分级,测算信噪比(signal-to-noise ratio,SNR)和对比噪声比(contrast-to-noise ratio,CNR),判断淋巴结与周围血管的关系,并以手术病理结果为金标准进行统计学分析。结果4个不同的静脉团注流速组(1.5 mL/s、2.0 mL/s、2.5 mL/s、3.0 mL/s)评分平均值分别为1.375±0.405、1.446±0.375、1.953±0.351、1.422±0.428,SNR分别是6.363±0.474、5.028±0.510、6.320±0.325、6.638±0.446,CNR分别是4.345±1.670、5.528±1.794、5.506±1.143、5.376±1.569,4组对显示乳腺癌腋窝淋巴结与周围血管关系无明显影响(P>0.05)。不同的延迟扫描时间显示腋窝血管上有差异(P<0.05),早期组和晚期组评分平均值分别为1.561±1.001和2.250±1.443,SNR分别是5.966±1.699和6.791±1.926,CNR分别是5.506±0.829和5.504±0.825。早期和晚期延迟时间显示血管也有差异(P<0.05),通过与乳腺手术评估结果对比,时相20显示效果最好,时相25~30与时相20显示效果接近,晚期延迟时间显示效果高于早期。结论mDIXON-MRA技术中不同团注流速和延迟扫描时间的显示腋窝淋巴结和血管关系的效果不同,本研究推荐选择团注流速1.5 mL/s,延迟扫描时间150 s最佳。

Objective:To evaluate the relationship between axillary lymph nodes and blood vessels in breast cancer by using the technique of mDIXON-MRA,and to explore the influence of different bolus injection rate and delayed scanning time on image quality.Materials and Methods:Using Philips INGENIA 3.0 T DNA MR scanner,we collected the MR diffusion weighted imaging(DWI)and vascular imaging of the armpit region of 77 patients with clinically confirmed breast cancer from December 2018 to January 2020.The patients were divided into four groups,and the bolus injection rate was 1.5 mL/s,2.0 mL/s,2.5 mL/s,3.0 mL/s,respectively.After post-processing and reconstruction,two radiologists evaluated and graded the images respectively,measured and calculated signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR),judged the relationship between lymph nodes and peripheral blood vessels,and made statistical analysis based on the gold standard of clinical pathological results.Results:The mean values of the four groups(1.5 mL/s,2.0 mL/s,2.5 mL/s,3.0 mL/s)were 1.375±0.405,1.446±0.375,1.953±0.351 and 1.422±0.428,respectively.The mean values of SNR were 6.363±0.474,5.028±0.510,6.320±0.325,6.638±0.446,and the mean values of CNR were 4.345±1.670,5.528±1.794,5.506±1.143,5.376±1.569.There was no significant effect on the relationship between axillary lymph nodes and peripheral blood vessels(P>0.05).Different delayed scanning time showed the difference of axillary vessels(P<0.05).The average score of early group and late group was 1.561±1.001 and 2.250±1.443,respectively.The average values of SNR were 5.966±1.699,6.791±1.926,and the average values of CNR were 5.506±0.829,5.504±0.825.The delay time of early and late group also showed the difference(P<0.05).Compared with the evaluation results of breast surgery,the best evaluation effect is phase 20,and the evaluation effect is similar from phase 25 to phase 30 and phase 20,and the effect of late delay time is higher than that of early.Conclusions:The effect of different injection bolus rate and delayed scanning time on showing the relationship between axillary lymph nodes and blood vessels is different by using mDIXON-MRA technology.In this study,the injection bolus rate of 1.5 mL/s and delayed scanning time of 150 seconds are recommended to be the best.