Zhao Jing, Hamm Bernd, Brenner Winfried, Makowski Marcus R
Institute of Radiology and Nuclear Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117, Berlin, Germany.
Institute of Nuclear Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Augustenburger Platz 1, 13353, Berlin, Germany.
Insights Imaging. 2020 Dec 17;11(1):137. doi: 10.1186/s13244-020-00926-y.
This study aimed to calculate an applicable relative ratio threshold value instead of the absolute threshold value for simultaneous Ga prostate-specific membrane antigen/positron emission tomography ([Ga]Ga-PSMA-11 PET) in patients with prostate cancer (PCa).
Our study evaluated thirty-two patients and 170 focal prostate lesions. Lesions are classified into groups according to Prostate Imaging Reporting and Data System (PI-RADS). Standardized uptake values maximum (SUVmax), corresponding lesion-to-background ratios (LBRs) of SUVmax, and LBR distributions of each group were measured based on regions of interest (ROI). We examined LBR with receiver operating characteristic analysis to determine threshold values for differentiation between multiparametric magnetic resonance imaging (mpMRI)-positive and mpMRI-negative lesions.
We analyzed a total of 170 focal prostate lesions. Lesions number of PI-RADS 2 to 5 was 70, 16, 46, and 38. LBR of SUVmax of each PI-RADS scores was 1.5 (0.9, 2.4), 2.5 (1.6, 3.4), 3.7 (2.6, 4.8), and 6.7 (3.5, 12.7). Based on an optimal threshold ratio of 2.5 to be exceeded, lesions could be classified into MRI-positive lesion on [Ga]Ga-PSMA PET with a sensitivity of 85.2%, a specificity of 72.0%, with the corresponding area under the receiver operating characteristic curve (AUC) of 0.83, p < 0.001. This value matches the imaging findings better.
The ratio threshold value of SUVmax, LBR, has improved clinical and research applicability compared with the absolute value of SUVmax. A higher threshold value than the background's uptake can dovetail the imaging findings on MRI better. It reduces the bias from using absolute background uptake value as the threshold value.
本研究旨在计算一个适用于前列腺癌（PCa）患者的相对比值阈值，以替代同时进行镓前列腺特异性膜抗原/正电子发射断层扫描（[Ga]Ga-PSMA-11 PET）时的绝对阈值。
我们的研究评估了32例患者和170个前列腺局灶性病变。病变根据前列腺影像报告和数据系统（PI-RADS）进行分组。基于感兴趣区域（ROI）测量标准化摄取值最大值（SUVmax）、SUVmax相应的病变与背景比值（LBR）以及每组的LBR分布。我们通过接受者操作特征分析检查LBR，以确定多参数磁共振成像（mpMRI）阳性和mpMRI阴性病变之间的鉴别阈值。
我们共分析了170个前列腺局灶性病变。PI-RADS 2至5级的病变数量分别为70、16、46和38个。每个PI-RADS评分的SUVmax的LBR分别为1.5（0.9，2.4）、2.5（1.6，3.4）、3.7（2.6，4.8）和6.7（3.5，12.7）。基于超过2.5的最佳阈值比值，病变在[Ga]Ga-PSMA PET上可被分类为MRI阳性病变，灵敏度为85.2%，特异性为72.0%，相应的接受者操作特征曲线下面积（AUC）为0.83，p < 0.001。该值与影像学表现更匹配。
与SUVmax的绝对值相比，SUVmax的比值阈值LBR提高了临床和研究适用性。高于背景摄取的阈值能更好地与MRI上的影像学表现相吻合。它减少了将绝对背景摄取值用作阈值所带来的偏差。
