3D CUBE与2D T2加权成像技术应用于直肠癌新辅助治疗后再分期的比较:一项诊断试验

Rectal cancer restaging using 3D CUBE vs.2D T2-weighted technique after neoadjuvant therapy:a diagnostic study

目的本研究旨在比较3D CUBE序列与2D T2加权快速自旋回波(FSE)序列用于直肠癌新辅助治疗后再分期的价值。方法:本回顾性研究纳入了72例经肠镜和病理活检证实的直肠癌患者。新辅助治疗后,所有病例接受盆腔磁共振成像(MRI)检查,1.5T MRI扫描序列包括层厚1.4 mm的冠状位3D CUBE T2加权FSE序列和层厚为5 mm的矢状位、冠状位及轴位2D T2加权FSE序列。记录两种序列总的收集时间。以术后病理为金标准,评估两种成像技术的再分期准确性。绘制受试者操作特征(ROC)曲线并计算曲线下面积(AUC)。结果:阅片人一判断3D T2加权成像和2D T2加权成像对T分期的诊断准确率分别为81.9%和72.2%,阅片人二分别为86.1%和75.0%。判断肿瘤是否突破肌层时,3D序列的AUC明显高于2D序列(阅片人一:0.878 vs.0.783;阅片人二:0.905 vs.0.796;均P<0.05)。而在判断是否有淋巴结转移时,两种序列AUC的差异无统计学意义(阅片人一:0.719 vs.0.698;阅片人二:0.740 vs.0.698,均P>0.05)。在肠壁显示度、肿瘤显示度和总体图像质量方面,两种序列的差异均无统计学意义(均P>0.05)。但相较于2D序列,3D序列收集时间更短,信号强度比率更高(均P<0.05)。结论:相较于2D T2加权FSE序列,3D CUBE T2加权序列能更准确地对新辅助治疗后的直肠癌进行再分期,而且其扫描时间更短,并能进行多方位的图像重建。

Objective.This study aimed to compare the accuracy of rectal cancer restaging after neoadjuvant therapy with 3D CUBE sequence with 2D T2-weighted fast spin-echo(FSE)sequence.Methods.This retrospective study comprised 72 patients with rectal cancer confirmed by colonoscopy and biopsy.After neoadjuvant therapy,all patients underwent pelvic magnetic resonance imaging(MRI)examination at 1.5T MRI sequences including a single coronal 3D CUBE T2-weighted FSE sequence with 1.4mmthickness and a 2D T2-weighted FSE sequence in the sagittal,coronal and axial planes with 5mmthickness.The total acquisition time of the two sequences was recorded.Results were compared with postsurgical pathology(gold standard).The diagnostic accuracy was evaluated;and receiver operating characteristic(ROC)curves and the area under the curves(AUC)were calculated.Results.The T category staging accuracy of 3D T2WI and 2D T2WI was 81.9% and 72.2%,respectively,for reviewer 1 and 86.1% and 75.0% for reviewer 2.The AUC of 3D was higher than that of 2D(0.878 vs.0.783 for reader 1 and 0.905 vs.0.796 for reader 2;both P<0.05)when judging whether the tumor broke through themuscle layer.There was no significant difference between 3D and 2D in judging whether lymph nodes weremalignant(AUC 0.719 vs.0.698 for reader 1 and 0.740 vs.0.698 for reader 2;both P>0.05).There were no significant differences in the visibility of the rectal wall layer,tumor lesion and the overall image quality(all P>0.05).Compared with 2D sequences,the 3D sequence had shorter acquisition time and higher signal intensity ratio(both P<0.05).Conclusion.3D CUBE T2-weighted sequences offer better diagnostic accuracy in rectal cancer restaging after neoadjuvant therapy when compared with 2D T2-weighted FSE sequences;it has a shorter scanning time and more versatility of orientation reconstruction.