基于T2WI与DWI的磁化传递技术在前列腺癌诊断及分级中的应用

Application of magnetization transfer imaging combined with DWI and T2WI in diagnosis and grading of prostate cancer

目的探讨磁化传递成像(magnetization transfer imaging,MTI)在前列腺癌(prostate cancer,PCa)诊断及分级中的应用价值。材料与方法回顾性分析134例临床疑诊PCa的患者临床及影像资料,所有患者均完成基于T2WI与扩散加权成像(diffusion-weighted imaging,DWI)序列的MTI检查。根据病理结果,把所有患者分为良性前列腺增生(benign prostatic hyperplasia,BPH)组和PCa组;根据Gleason分级分组(Gleason grade groups,GGG)系统将PCa进一步分为低级别(low score,Ls)组和高级别(high score,Hs)组。分析MTI应用于前列腺的可行性;比较施加磁化传递(magnetization transfer,MTr)脉冲前后,T2WI与DWI诊断PCa及识别高级别PCa的效能;进一步比较BPH与PCa组、Ls与Hs组磁化传递率(magnetization transfer ratio,MTR)的差异。结果基于T2WI与DWI序列的MTI图像质量佳,同一研究者前后2次及不同研究者间MTR测值一致性高。DWI序列施加MTr后,在PCa的诊断(MTr前AUC=0.779,MTr后AUC=0.850)以及高低级别PCa的鉴别上(MTr前AUC=0.697,MTr后AUC=0.818)诊断效能均有效提升。在进一步的MTR组间对比中,BPH与PCa组、Ls组与Hs组T2WI-MTR差异无统计学意义(P=0.06;P=0.59),而DWI-MTR差异均有显著统计学意义(P=0.01;P=0.01)。结论MTI技术有助于提升DWI序列的PCa诊断效能,同时能进一步提高其识别高级别PCa的能力;DWI-MTR在PCa诊断及分级中存在巨大潜力。

Objective:To determine the value of magnetization transfer imaging(MTI)in diagnosing prostate cancer(PCa)and assessing the histologic grade.Materials and Methods:This study was conducted prospectively.A total of 134 patients with clinical suspicion of PCa underwent biparametric MRI with magnetization transfer(MTr)technology,and followed by biopsy or radical prostatectomy.According to the results of pathologic diagnosis,all patients were divided into two groups PCa and benign prostatic hyperplasia(BPH).The patients in PCa group were divided into low-and high score groups(Ls group and Hs group)based on the new Gleason grade groups(GGG)system.The feasibility of MTr in prostate imaging is evaluated.The magnetization transfer ratio(MTR)were compared between the PCa group and BPH group,and prior to the different grade in PCa group.The efficacy of T2WI and diffusion-weighted imaging(DWI)sequences with or without MTr pulse in the diagnosis of PCa and the stratification of low-or high-grade PCa was compared.Results:After applying MTr technology,the image quality of T2WI and DWI images were optimized.There was high consistency of MTR measure between intraobserver and interobserver.After MTr pulse was applied to DWI sequence,the diagnostic efficacy of PCa(pre-MTr AUC=0.779,post-MTr AUC=0.850)and the differentiation of Ls and Hs(pre-sMTr AUC=0.697,post-MTr AUC=0.818)were effectively improved.Measured the MTR between BPH and PCa group,a significant difference between groups was found in the DWI sequence trial(t=-1.85,P=0.06),but not in the T2 sequence trial(t=-3.39,P=0.01).Measured the MTR between Ls group and Hs group,a statistically insignificant difference was found in the T2WI sequence trial(t=-0.53,P=0.59),but not in the DWI sequence trial(t=3.42,P=0.01).Conclusions:MTI can improve the performance for the PCa detect and identify high grade lesions,especially the MTR in DWI sequence showed great potential in diagnosing and grading PCa.