RS-EPI序列在前列腺肿瘤DWI中的临床应用价值

Clinical application value of readout-segmented echo-plannar imaging sequence in prostate tumors with diffusion weighted imaging

目的：通过比较前列腺肿瘤的分段读出平面回波成像（RS—EPI）和单次激发平面回波成像（SS-EPI）的影像表现，探讨RS-EPI在前列腺肿瘤诊断中的应用价值。方法：回顾性分析34例行3．0TMRISS-EPI和RS-EPI检查并经穿刺活检确诊为前列腺肿瘤患者的病例资料。由两位影像医生在不提供任何临床及MRI序列信息的情况下，针对扩散加权成像（DWI）图像的病灶显示清晰程度、几何变形、空间分辨力、诊断信心四个方面按5个等级（1～5分）进行独立评分，由第三位影像医生在工作站上半定量测量图像的信噪比（SNR）、对比度和对比噪声比（CNR）并进行统计学分析。结果：RS-EPI序列上病灶显示清晰程度（K=0．649，P〈0．001）、图像变形（K=0．599，P〈0．001）、空间分辨力（K=0．768，P〈0．001）、诊断信心（K=0．622，P〈0．001）等方面，两位医师的评分具有良好的一致性。SS-EPI序列上，病灶显示清晰程度（K=0．587，P〈0．001）、图像变形（K=0．554，P〈0．001）、空间分辨力（K=0．640，P〈0．001）、诊断信心（K=0．597，P〈0．001）等方面，两位医师的评分具有良好的一致性。RS-EPI和sS-EPI序列的平均分值如下：病灶显示清晰程度分别为4．56和3．85分，几何变形分别为4．34和3．28分，空间分辨力分别为4．41和2．84分，诊断信心分别为4．34和3.74分，SNR分别为173．49和234．78，对比度分别为6．29和7．23，CNR分别为144．98和202．13。结论：基于RS-EPI序列的高分辨力DWI与SS-EPI序列相比明显提高了图像质量，更有利于前列腺肿瘤的显示。

Objective：To compare the clinical utility of readout-segmented echo-planar imaging （RS-EPI） with single- shot echo-planar imaging （SS-EPI） and explore the value of RS-EPI in the diagnosis of prostatic neoplasms. Methods： RS- EPI and SS-EP1 diffusion weighted images of prostatic neoplasm patients were obtained using 3.0T MR before ultrasound guided systemic biopsy. Two radiologists, unaware of the clinical data and sequences, retrospectively and independently in- terpreted MR images, which consisted of lesion conspicuity, distortion, resolution, and diagnostic confidence, and these were graded using a 5-point Likert scale. Signal-to-noise ratio （SNR） and contrast-to-noise ratio （CNR） calculations were made by a third radiologist. Results： There was good reader agreement in the scores, RS-EPI sequence： lesion eonspicuity （κ=0.649,P〈0.001）,distortion （κ=0. 599,P〈0. 001）,resolution （κ=0. 768,P〈0. 001） and diagnostic confidence （κ= 0. 622, P〈0.001）. SS-EPI sequence ： lesion conspicuity （κ= 0. 587, P〈0. 001 ）, distortion （κ= 0.554, P〈0.001 ）, resolution （κ=0. 640,P〈0. 001） and diagnostic confidence （κ=0. 597,P〈0. 001）. The mean scores for SS-EPI and RS-EPI were as follows：lesion conspicuity 4.56 and 3.85, distortion 4.34 and 3.28, resolution 4.41 and 2.84 and diagnostic confidence 4.34 and 3.74. The SNR,C,CNR for RS-EPI were lower than those for SS-EPI. SNR：173.49 and 234.78, C： 6.29 and 7.23, CNR： 144.98 and 202. 13. Conclusion：RS-EPI DWI images show improved image quality as compared to SS-EPI for produ- cing high-resolution DWI which favours the manifestation of prostate neoplasms.