1.5T超高b值DWI联合常规序列诊断前列腺癌的准确度

Accuracy of 1.5T ultra-high b-value DWI combined with routine sequence in diagnosis of prostate cancer

目的探讨1.5T超高b值弥散加权成像(DWI)联合常规序列对前列腺癌(PCa)的诊断准确度。方法68例临床怀疑PCa患者行MRI扫描,2名医师分别采取3种方案诊断PCa:在常规序列T1WI和T2WI扫描的基础上,方案A联合DWI序列b=1000 s/mm^2,方案B联合DWI序列b=2000 s/mm^2,方案C联合DWI序列b=1000、2000 s/mm^2。以超声引导下穿刺活检结果为金标准,比较三种方案诊断PCa的效能。结果52例患者确诊为PCa。方案A、方案B诊断一致性差(Kappa=0.352、0.386,P<0.01),方案C诊断一致性中等(Kappa=0.679,P<0.01)。与方案A比较,医师1和医师2采用方案B的AUC增大(0.850 vs.0.688,Z=2.357,P=0.02;0.919 vs.0.730,Z=3.110,P<0.01),医师1和医师2采用方案C的AUC亦增大(0.951 vs.0.688,Z=3.952,P<0.01;0.968 vs.0.730,Z=4.146,P<0.01)。结论DWI序列(b=2000 s/mm^2)联合常规序列有助于诊断PCa,DWI序列(b=1000、2000 s/mm^2)联合常规序列可提高PCa诊断的准确度。

Objective To investigate the diagnostic accuracy of ultra-high b-value diffusion weighted imaging(DWI)combined with conventional sequence for prostate cancer(PCa).MethodsSixty-eight patients clinically suspected to be PCa underwent MRI scanning using three schemes adopted by two doctors.On the basis of conventional T1 WI and T2 WI scanning,the scheme A was conducted by combined use of DWI sequence with a b-value of 1000 s/mm^2,the scheme B was conducted by combined use of DWI sequence with a b-value of 2000 s/mm^2,and the scheme C was conducted by combined use of DWI sequence with the b-values of 1000 s/mm^2 and 2000 s/mm^2.Ultrasound-guided biopsy was taken as gold standard and the diagnostic efficacy of three schemes was compared.Results Of 68 patients,52 were pathologically diagnosed as PCa.The diagnostic consistency of scheme A and scheme B was poor(Kappa=0.352 and 0.386,P<0.01),which of scheme C was moderate(Kappa=0.679,P<0.01).Compared with scheme A,the area under curve(AUC)of scheme B adopted by doctor 1 and doctor 2 was larger(0.850 vs.0.688,Z=2.357,P=0.02 and 0.919 vs.0.730,Z=3.110,P<0.01),and AUC of scheme C adopted by doctor 1 and doctor 2 was also larger(0.951 vs.0.688,Z=3.952,P<0.01 and 0.968 vs.0.730,Z=4.146,P<0.01).Conclusion On the basis of conventional T1 WI and T2 WI scanning,combined use of DWI sequence with a b-value of 2000 s/mm^2 is helpful to diagnosing PCa and combined use of DWI sequence with the b-values of 1000 s/mm^2 and 2000 s/mm^2 can improve the diagnostic accuracy of PCa.