比较小视野多激发平面回波序列DWI与常规单激发平面回波序列DWI在直肠癌中的应用价值

The Comparison of the Application Value of Reduced Field of View Image Reconstruction Using Image-Space Sampling Function and Full Field of View Single-Shot Echo-Planar Imaging DWI in Rectal Cancer

目的:比较直肠癌小视野(rFOV)基于图像空间重建(IRIS)技术弥散加权成像(rFOV IRIS-DWI)序列与常规视野(fFOV)单激发平面回波成像(ssEPI)DWI(ssEPI-DWI)序列的图像质量。方法:回顾性收集2022年10月—2023年8月于我院进行直肠MRI检查的30例直肠癌患者资料。入组患者均采用3.0 T MR扫描仪进行检查,均完成rFOV IRIS-DWI序列、ssEPI-DWI序列扫描。所有图像均传至Philips IntelligenceSpace Portal后处理工作站分析。由一名具有20年以上直肠癌MRI诊断经验的高级职称医生,分别在b=800 mm^(2)/s和b=1000 mm^(2)/s的DWI图像上评估2组图像质量:主观评价采用5分制评分,包括总体图像质量、图像伪影、图像变形、病变对比度、图像解剖结构;客观评价包括肿瘤最大层面面积、平均最大面积、信噪比(SNR)和对比度噪声比(CNR)。采用SPSS 26.0统计软件进行数据分析。2组DWI图像质量主观评分比较采用配对Wilcoxon秩和检验,客观评价指标比较采用配对样本t检验。结果:rFOV IRIS-DWI序列主观评价中的图像总体质量、变形、伪影、对比度、解剖结构均优于fFOV ssEPI-DWI序列(P<0.05)。rFOV IRIS-DWI序列、fFOV ssEPI-DWI序列的主观评价总分分别为20.6分、17.4分,差异具有统计学意义(P<0.05)。rFOV IRIS-DWI序列的肿瘤最大层面面积、平均最大面积均大于fFOV ssEPI-DWI序列(P<0.05)。结论:相对于fFOV ssEPI-DWI序列,rFOV IRIS-DWI序列能明显提高直肠癌图像分辨率,减轻磁敏感伪影和图像变形,提高图像质量。

Purpose:To compare the image quality of reduced field of view(rFOV)image-space sampling function DWI(rFOV IRIS-DWI)sequence and fFOV single-shot echo-planar imaging DWI(fFOV ssEPI-DWI)sequence in rectal cancer.Methods:The data of 30 patients with rectal cancer who underwent rectal MRI examination in our institution between October 2022 and August 2023 were retrospectively collected.All patients underwent MRI examination by a 3.0 T MR scanner(Ingenia Elition,Philips,Netherlands)using rFOV IRIS-DWI sequence and fFOV ssEPI-DWI sequence.All DWI images were uploaded to Philips Intelligence Space Portal postprocessing workstation for evaluation and analysis.One senior radiologist with over 20 years of experience in the MRI diagnosis of rectal cancer randomly evaluated the images of rFOV IRIS-DWI sequence with b=800 mm^(2)/s and fFOV ssEPI-DWI sequence with b=1000 mm^(2)/s,respectively.Subjective evaluation of image quality including overall image quality,image artifacts,image distortion,lesion contrast and image anatomical details were performed according to a 5-point scale reference.And the objective evaluation of image quality including maximum area of tumor,average maximum area of tumor,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were also performed.SPSS 26.0 statistical software was used for data analysis.Paired Wilcoxon rank sum test was used to compare the subjective scores of image quality between rFOV IRIS-DWI sequence and fFOV ssEPI-DWI suquence,and paired sample t test was used to compare the objective image quality between the two DWI sequences.Results:The overall image quality,image distortion,artifacts,contrast,and the detail of anatomical structure in the rFOV IRIS-DWI sequence were significantly better than in the fFOV ssEPI-DWI sequence(P<0.05).The total scores of the subjective evaluation in the rFOV IRIS-DWI sequence and fFOV ssEPI-DWI sequence were 20.6 and 17.4,respectively,and the difference was statistically significant(P<0.05).The maximum area and average maximum area of rFOV IRIS-DWI sequence were larger than that in the fFOV ssEPI-DWI sequence(P<0.05).Conclusion:Compared to fFOV ssEPI-DWI sequence,rFOV IRIS-DWI sequence can significantly improve the images resolution,reduce sensitivity artifacts and image distortion,and improve image quality in rectal cancer patients.