68Ga-PSMA-11 PET/MR多参数成像对初诊前列腺癌的诊断

目的探讨⁶⁸Ga-前列腺特异膜抗原(PSMA)-11 PET/MR多参数多模态功能成像对初诊前列腺癌的诊断价值,并分析其对前列腺癌诊断和分期的效能。方法前瞻性收集2019年7月至2019年9月符合纳入标准的45例疑似或活组织检查(简称活检)确诊的前列腺癌患者(平均年龄69岁),在南京市第一医院行⁶⁸Ga-PSMA-11 PET/MR检查。以感兴趣区(ROI)方法在融合图像上半定量分析肿瘤放射性摄取,以最大标准摄取值(SUV_max)表示,测量肿瘤代谢体积(MTV)、平均标准摄取值(SUV_mean)并计算肿瘤组织PSMA表达负荷(SUV_mean×MTV);在MRI表观弥散系数(ADC)图(b=1500 s/mm2)测取ROI的ADC值。以病理结果为参考评价⁶⁸Ga-PSMA-11 PET/MR在术前诊断前列腺癌的效能及对临床分期的影响。采用Pearson相关分析前列腺癌组织放射性摄取、PSMA表达负荷、ADC值与前列腺特异抗原(PSA)的相关性;采用两独立样本t检验分析数据。结果病理检测45例患者中,前列腺癌38例,其中12例发生转移;前列腺增生(BPH)7例。⁶⁸Ga-PSMA-11 PET/MR检测出39例前列腺癌,其中1例为假阳性。⁶⁸Ga-PSMA-11 PET/MR诊断前列腺癌的灵敏度、特异性、阳性预测值、阴性预测值、准确性分别为100%(38/38)、6/7、97.4%(38/39)、6/6、97.8%(44/45)。前列腺癌肿瘤常呈局灶性放射性摄取,T2加权成像(WI)呈低信号,弥散受限;BPH常呈轻度不均匀摄取,T2WI、弥散加权成像(DWI)弥漫信号不均。前列腺癌的SUV_max明显高于BPH(24.66±19.21与4.97±2.13;t=5.208,P<0.001);ADC值明显低于BPH[(0.91±0.37)×10^-3与(1.08±0.24)×10^-3 mm/s²;t=2.816,P<0.05]。前列腺癌的SUV_max、PSMA表达负荷与PSA值呈正相关(r值:0.42和0.71,均P<0.05);ADC值与PSA值呈负相关(r=-0.37,P=0.013)。结论⁶⁸Ga-PSMA-11 PET/MR对初诊前列腺癌的诊断及早期分期有明显优势。

68Ga-PSMA-11 PET/MR multiparameter imaging in the diagnosis of naive prostate cancer

Objective To explore the diagnostic value of ⁶⁸Ga-prostate specific membrane antigen(PSMA)-11 PET/MR multiparameter multimodal functional imaging in the diagnosis of naive prostate cancer(PCa),and to analyze its efficacy in the early stages of PCa.Methods From July to September 2019,45 suspected or pathologically confirmed PCa patients(average age:69 years)who met the inclusion criteria were collected to perform ⁶⁸Ga-PSMA-11 PET/MR examination in Nanjing First Hospital.After the scanning was completed,the method of region of interest(ROI)was used to semi-quantitatively calculate the tumor radioactive uptake in the fusion image,including the maximum standardized uptake value(SUV_max),tumor metabolic volume(MTV)and mean standardized uptake value(SUV_mean),and PSMA expression load was calculated(SUV_mean×MTV).Apparent diffusion coefficient(ADC)values of ROI were measured in ADC images(b=1500 s/mm2).The efficacy of ⁶⁸Ga-PSMA-11 PET/MR in the preoperative diagnosis of PCa and the effect on clinical staging were evaluated with the pathological results.The correlation between prostate specific antigen(PSA)and radiation uptake in PCa tissues,PSMA expression load and ADC values was analyzed by Pearson correlation.Independent-sample t test was used to analyze the data.Results Pathologically,38 of the 45 patients were with PCa and 7 patients had benign prostatic hypertrophy(BPH),and metastasis occurred in 12 of the 38 PCa patients.⁶⁸Ga-PSMA-11 PET/MR detected 39 cases of PCa with one of which was false-positive.The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of ⁶⁸Ga-PSMA-11 PET/MR were 100%(38/38),6/7,97.4%(38/39),6/6 and 97.8%(44/45),respectively.The tumor tissues of PCa often showed focal radioactive uptake,and the T2 weighted imaging(WI)showed focal low signal and limited dispersion.BPH showed slightly uneven uptake,and T2WI and diffusion weighted imaging(DWI)showed uneven diffuse signals.SUV_max of PCa was significantly higher than that of BPH(24.66±19.21 vs 4.97±2.13;t=5.208,P<0.001).ADC values of PCa were significantly lower than that of BPH((0.91±0.37)×10^-3vs(1.08±0.24)×10^-3 mm/s²;t=2.816,P<0.05).SUV_max and the expression loads of PSMA in PCa were positively correlated with PSA(r values:0.42 and 0.71,both P<0.05).ADC values of tumor tissues in PCa were negatively correlated with PSA(r=-0.37,P=0.013).Conclusion ⁶⁸Ga-PSMA-11 PET/MR has great merits in the early diagnosis and staging of PCa.