Combination of 68 Ga-PSMA PET/CT and multiparameter MRI improves the detection of clinically significant prostate cancer: a lesion by lesion analysis

Purpose: To explore whether 68 Ga-PSMA PET/CT (PET/CT) or the combination of mpMRI and 68 Ga-PSMA PET/CT (com-MRI/PET) can improve the detection of csPCa. Methods: We retrospectively enrolled 54 patients who underwent both mpMRI and PET/CT before radical prostatectomy. Regions of interest (ROI) on imaging from mpMRI, PET/CT and pathology were marked. A lesion was defined when ROI was marked in the same location on continuous imaging at any of the imaging setting. All lesions were recorded by Prostate Imaging Reporting and Data System (PI-RADS), miPSMA expression score (MI-ES) and pathology results and analyzed. The diagnostic performance was analyzed by receiver operating characteristics (ROC) analysis. Specific improvement for lesions with different PI-RADS score and were analyzed by net reclassification improvement (NRI). Results: Totally, 90 lesions from 54 patients were analyzed, among which 66 lesions were csPCa. ROC analysis showed improvement of com-MRI/PET comparing with mpMRI for csPCa detection (Δ area under the curves (ΔAUC) 0.06; 95% CI, 0.01–0.12; p<0.05). With calculated cutoff, com-MRI/PET has a significant overall improvement compared with mpMRI (NRI, 21.9%, p<0.01), with an improvement on sensitivity (89% versus 76%, p<0.01) and no sacrifice on specificity (96% versus 88%, p>0.05). Diagnostic improvement for csPCa detection happened on lesions with PI-RADS 3 (NRI 66.7%, P<0.01). Conclusions: The com-MRI/PET improves the detection of csPCa for lesions with PI-RADS 3.

目的：探讨68Ga - PSMA PET/CT（正电子发射断层扫描/计算机断层扫描）或多参数磁共振成像（mpMRI）与68Ga - PSMA PET/CT联合（com - MRI/PET）是否能提高临床显著性前列腺癌（csPCa）的检测率。 方法：我们回顾性纳入了54例在根治性前列腺切除术前均接受了mpMRI和PET/CT检查的患者。标记mpMRI、PET/CT影像以及病理上的感兴趣区域（ROI）。当在任何一种影像设置下连续影像的同一位置标记出ROI时，则定义为一个病灶。所有病灶均按照前列腺影像报告和数据系统（PI - RADS）、微小PSMA表达评分（MI - ES）以及病理结果进行记录和分析。通过受试者工作特征（ROC）分析诊断效能。通过净重分类改善（NRI）分析对不同PI - RADS评分病灶的特定改善情况。 结果：共分析了54例患者的90个病灶，其中66个病灶为csPCa。ROC分析显示，在csPCa检测方面，com - MRI/PET相较于mpMRI有所改善（曲线下面积差值（ΔAUC）为0.06；95%置信区间为0.01 - 0.12；p < 0.05）。通过计算临界值，与mpMRI相比，com - MRI/PET总体上有显著改善（NRI为21.9%，p < 0.01），敏感性提高（89%对76%，p < 0.01），特异性无降低（96%对88%，p > 0.05）。在PI - RADS评分为3的病灶上，csPCa检测的诊断改善情况明显（NRI为66.7%，P < 0.01）。 结论：对于PI - RADS评分为3的病灶，com - MRI/PET可提高csPCa的检测率。