双参数MRI诊断前列腺癌的价值与假阳性原因分析

Value of biparametric MRI in diagnosis of prostate cancer and false positive analysis

目的探讨双参数磁共振成像(BPMRI)在前列腺癌鉴别诊断中的价值,总结分析BPMRI出现假阳性的原因。方法选择66例前列腺肿瘤患者,年龄54~90岁,平均年龄72.56岁;前列腺特异性抗原(PSA)3.7~336.0 ng/mL。MRI采集序列包括横断位T1加权成像(T1WI)、T2加权成像(T2WI)、压脂T2WI和弥散加权成像(DWI),冠状位T2WI。每个病例分析1个病灶,有多个病灶时以T2WI信号最低且体积最大的一个为目标病灶。行超声引导穿刺术后标本,做病理诊断。计算BPMRI诊断的灵敏度、特异度和正确率。结果 66例患者中前列腺癌31例(恶性组),前列腺良性疾病35例(良性组)。良性组前列腺增生(BPH)22例,前列腺炎4例,BPH伴炎症9例。BPMRI诊断PCa的灵敏度、特异度分别是83.87%、77.14%,阳性预测值、阴性预测值分别是76.47%、84.38%,总的诊断正确率80.30%,Youden指数为0.610。表观扩散系数(ADC)以小于0.90×10^(-3)mm^(2)/s为临界值(b=2 000),诊断PCa的灵敏度、特异度分别为77.10%、87.10%,Youden指数为0.642,曲线下面积为0.870。结论 BPMRI在前列腺肿瘤良恶性鉴别诊断中具有较高的价值,但需要鉴别假阳性结果。

Objective To detect value of biparametric magnetic resonance imaging(BPMRI) in differential diagnosis of prostate cancer, and analyze causes of false positives in BPMRI. Methods A total of 66 patients with prostate tumor were enrolled,which aged 54-90 years old with mean age of 72.56 years old. The prostate specific antigen(PSA) was 3.7-336.0 ng/mL.The MRI acquisition sequences included conventional T1 weighted imaging(T1 WI), T2 weighted imaging(T2 WI), fat-suppression T2 WI and diffusion weighted imaging(DWI) in transversal position, and T2 WI in coronary position. One lesion in each case was analyzed, and the lowest T2 WI signal and the largest volume were set as the target lesion in multiple lesions. The ultrasoundguided puncture was performed to obtain postoperative specimens for pathological diagnosis. The sensitivity, specificity and accuracy of BPMRI diagnosis were calculated. Results Of 66 cases, 31 cases were prostate cancer(malignant group), and 35 cases were benign prostate(benign group). The benign group included 22 cases of benign prostate hyperplasia(BPH), 4 of prostate inflammation and 9 of BPH with inflammation. The sensitivity and specificity of BPMRI in diagnosis of PCa were83.87 % and 77.14 %, positive predictive value and negative predictive value were 76.47 % and 84.38 %, the total diagnostic accuracy rate was 80.30 %, and Youden index was 0.610. The critical value of apparent diffusion coefficient(ADC) was less than 0.90 × 10^(-3) mm^(2)/s(b = 2 000), sensitivity and specificity in diagnosis of PCa were 77.10 % and 87.10 %, the Youden index was 0.642 and area under curve was 0.870. Conclusion It is demonstrated that BPMRI showed good value in differential diagnosis of benign and malignant prostate cancer, but false positive results need to be identified.