双层探测器光谱CT对前列腺癌的诊断价值

Diagnostic value of dual-layer detector spectral CT for prostate cancer

目的:探讨双层探测器光谱CT对前列腺癌(prostate cancer,PCa)病灶的显示效果及对临床有意义前列腺癌(clinically significant prostate cancer,CsPCa)的诊断价值。方法:回顾性收集2019年10月至2022年7月经病理确诊的47例PCa患者的光谱图像,根据Gleason评分将患者分为CsPCa组(Gleason评分≥7分,28例)和临床无意义前列腺癌(clinically insignificant prostate cancer,CisPCa)组(Gleason评分=6分,19例)。由2名放射科医师采用独立盲法阅片,测量病灶的CT值、碘密度值(iodine concentration,IC)及有效原子序数值(Zeff)等,计算标准化碘浓度(normalized iodine concentration,NIC)及动脉增强分数(arterial enhancement fraction,AEF),并评价图像的主、客观质量。比较2组PCa患者之间光谱CT参数的差异,并绘制ROC曲线分析其诊断效能。结果:静脉期40 keV虚拟单能量图像(virtual monoenergetic image,VMI)的信噪比、对比噪声比及主观图像质量评分优于120 kVp常规CT图像和50~70 keV VMI,差异均具有统计学意义(P均<0.05),且2名医师评价结果一致性良好(Kappa值为0.613)。CsPCa组患者的前列腺特异抗原(PSA)水平、病灶大小、AEF以及动脉期光谱CT定量参数值大于CisPCa组,差异均有统计学意义(P均<0.05)。光谱定量参数中动脉期IC、AEF值鉴别CsPCa的效能高于其他参数,AUC值分别为0.793、0.752,差异无统计学意义(P>0.05);IC、AEF联合PSA对CsPCa的诊断效能优于IC、AEF单独诊断,AUC值为0.923,差异均有统计学意义(P均<0.05)。结论:光谱CT较常规CT能明显提高对PCa病灶的显示效果,其中静脉期40 keV VMI显示病灶最佳,且光谱CT定量参数有助于CsPCa的诊断,具有较高的临床价值,为PCa的术前无创检查提供了新的思路。

Objective To explore the display of prostate cancer(PCa)by dual-layer detector spectral CT,and analyze its diagnostic value for clinically significant prostate cancer(CsPCa).Methods The energy spectrum images of 47 patients with pathologically confirmed PCa admitted to a hospital from October 2019 to July 2022 were retrospectively collected.The patients were divided into a CsPCa group(Gleason score≥7,n=28)and a clinically insignificant prostate cancer(CisPCa)group(Gleason score=6,n=19)according to the Gleason score.Two radiologists measured the CT values,iodine concentration(IC)and effective atomic number(Zeff)values of the lesions independently and blindly,calculated the normalized iodine concentration(NIC)and arterial enhancement fraction(AEF)and evaluated the subjective and objective quality of the images.The differences in spectral CT parameters between the 2 groups of PCa patients were compared,and the ROC curves were plotted to analyze their diagnostic efficacy.Results The signal-to-noise ratio,contrast-to-noise ratio and subjective image quality scores of venous phase 40 keV virtual monoenergetic image(VMI)were higher than those of the 120 kVp conventional CT image and 50-70 keV VMI,with the difference statistically significant(P<0.05),and the two radiologists had high consistency with a Kappa value of 0.613.The prostate-specific antigen(PSA)level,lesion size and arterial phase energy spectrum quantitative parameters of the CsPCa group were significantly greater than those of the CisPCa group,and the differences were statistically significant(all P<0.05).Arterial phase IC and AEF were the most effective in differentiating CsPCa among the energy spectrum quantitative parameters,with the AUC values being 0.793 and 0.752 respectively,and the differences were not statistically significant(P>0.05);combined arterial phase IC and AFF with PSA behaved better than only arterial phase IC or AFF,with the AUC value being 0.923,and the differences were statistically significant(all P<0.05).Conclusion Spectral CT can significantly improve the display of PCa lesions when compared with the conventional CT,and venous-phase 40 keV VMI behaves the best in showing the lesions.The quantitative parameters of spectral CT contribute to the diagnosis of CsPCa,and a new idea is provided for preoperative noninvasive examination of PCa.[Chinese Medical Equipment Journal,2023,44(5):59-63]