基于压缩感知技术的自由呼吸DCE-VIBE序列在胃癌MR增强检查中的应用价值

Application Value of Free Breathing DCE-VIBE Sequence Based on Compressed Sensing Technology in Enhanced MR Examination of Gastric Cancer

目的通过对比分析常规三维容积内插屏气检查(Volumetric Interpolated Breath-Hold Examination,VIBE)序列与基于压缩感知(Compressed Sensing,CS)技术的动态增强磁共振成像(Dynamic Contrast-Enhanced Magnetic Resonance Imaging,DCE-MRI)VIBE(以下简称“CS-DCE-VIBE”)序列在胃癌MR增强检查中的图像质量,探索CS-DCE-VIBE序列在胃癌MR增强扫描中的的应用价值。方法选取行胃MR扫描的120例胃癌患者为研究对象。根据检查前呼吸训练的情况,将患者分为屏气良好组和屏气不佳组,每组各60例,扫描序列包括常规VIBE和CS-DCE-VIBE序列。获得图像后,由2名经验丰富的放射科医师对这2种图像上可测量的病变进行感兴趣区勾画,分别计算信噪比(Signal to Noise Ratio,SNR)和对比噪声比(Contrast to Noise Ratio,CNR),采用组内相关系数和配对样本t检验进行一致性评估及差异性分析。接着2名医师采用双盲法对2种序列图像进行主观评分,采用加权Kappa检验及Wilcoxon秩和检验进行一致性评估及差异性分析。结果2名医师测量计算SNR、CNR和主观评分的一致性好。屏气良好组和屏气不佳组CS-DCE-VIBE序列图像的SNR及CNR均高于常规VIBE序列,两者间差异均有统计学意义(P<0.001)。对于屏气良好组,CS-DCE-VIBE序列图像的主观评分低于常规VIBE序列,两者间差异有统计学意义(P<0.001);而对屏气不佳组,CS-DCE-VIBE序列图像的主观评分高于常规VIBE序列,两者间差异有统计学意义(P<0.001)。结论CS-DCE-VIBE序列可为胃癌患者术前影像评估提供可靠的扫描方案,尤其为呼吸配合差的胃癌患者提供更好的临床诊断方法。

Objective By comparing and analyzing the image quality of conventional three-dimensional volumetric interpolated breath-hold examination(VIBE)sequences and dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)VIBE sequences based on compressed sensing(CS)technology(hereinafter referred to as CS-DCE-VIBE)in gastric cancer MR enhancement examinations,to explore the application value of CS-DCE-VIBE sequences in gastric cancer MR enhancement scanning.Methods A total of 120 patients with gastric cancer who underwent gastric MR scanning were selected as the study objects.Based on pre examination breathing training,patients were divided into a good breath holding group and a poor breath holding group,with 60 cases in each group.The scanning sequences included routine VIBE and CS-DCE-VIBE sequence.After obtaining the images,the region of interest of measurable lesions on these two types of images were delineated,and the signal-to-noise ratio(SNR)and contrast to noise ratio(CNR)were calculated by two experienced radiologists.The intraclass correlation coefficient and paired sample t-test were used for consistency evaluation and difference analysis.Next,a double-blind method was used to subjectively score the two sequences of images by two radiologists,and consistency evaluation and difference analysis were conducted by using Kappa test and Wilcoxon rank sum test.Results The consistency between the measurement and calculation of SNR,CNR,and subjective scores calculated by two radiologists was good.The SNR and CNR of the CS-DCE-VIBE sequence images in good breath holding group and a poor breath holding group were higher than those in the conventional VIBE sequence,and the differences between them were statistically significant(P<0.001).For the group with good breath holding,the subjective evaluation score of CS-DCE-VIBE sequence images was lower than that of conventional VIBE sequences,and the difference between the two was statistically significant(P<0.001).For the group with poor breath holding,the subjective score of CS-DCE-VIBE sequence images was higher than that of conventional VIBE sequences,and the difference between the two was statistically significant(P<0.001).Conclusion The CS-DCE-VIBE sequence can provide a reliable scanning scheme for preoperative imaging evaluation of gastric cancer patients,especially for better clinical diagnostic methods for gastric cancer patients with poor respiratory coordination.