Department of Radiology and Molecular Imaging, Oakland University William Beaumont School of Medicine, Royal Oak, MI, United States of America.
Department of Urology, Oakland University William Beaumont School of Medicine, Royal Oak, MI, United States of America.
Clin Imaging. 2021 Dec;80:454-458. doi: 10.1016/j.clinimag.2021.09.003. Epub 2021 Sep 21.
Prostate volume and PSA density (PSAd) are important in the risk stratification of suspected prostate cancer (Pca). PI-RADS v2.1 allows for determining volume via segmentation or ellipsoid calculation. The purpose of our study was to compare ellipsoid and segmentation volume calculation methods and evaluate if PSAd diagnostic performance is altered.
We retrospectively assessed 397 patients (mean age/standard deviation: 63.7/7.4 years) who underwent MRI and prostate biopsy or prostatectomy, with Pca classified by Gleason ≥3 + 4 and ≥4 + 4 disease. Prostate total volumes were determined with ellipsoid calculations (TVe) and with semi-automated segmentation (TVs), along with inter-rater reliability with intraclass correlation coefficient (ICC). PSAd was calculated for TVe and TVs and ROC curves were created to compare performance for Gleason ≥3 + 4 and ≥4 + 4 disease.
TVe was significantly higher than TVs (p < 0.0001), with mean TVe = 55.4 mL and TVs = 51.0 mL. ROC area under the curve for PSAd derived with TVe (0.63, 95%CI:0.59-0.68) and TVs (0.64, 95%CI:0.59-0.68) showed no significant difference for Gleason ≥3 + 4 disease (p = 0.45), but PSAd derived with TVs (0.63, 95%CI: 0.58-0.68) significantly outperformed TVe (0.61, 95%CI: 0.57-0.67) for Gleason ≥4 + 4 disease (p = 0.02). Both methods demonstrated excellent inter-rater reliability with TVe with ICC of 0.93(95%CI: 0.92-0.94) and TVs with ICC of 0.98(95%CI: 0.98-0.99).
Traditional ellipsoid measurements tend to overestimate total prostate volume compared to segmentation, but both methods demonstrate similar diagnostic performance of derived PSA density for PI-RADS clinically significant disease. For higher grade disease, PSAd derived from segmentation volumes demonstrates statistically significant superior performance. Both methods are viable, but segmentation volume is potentially better.
前列腺体积和 PSA 密度（PSAd）在疑似前列腺癌（Pca）的风险分层中很重要。PI-RADS v2.1 允许通过分割或椭圆计算来确定体积。本研究的目的是比较椭圆和分割体积计算方法，并评估 PSAd 诊断性能是否改变。
我们回顾性评估了 397 名患者（平均年龄/标准差：63.7/7.4 岁），这些患者接受了 MRI 和前列腺活检或前列腺切除术，Pca 分类为 Gleason≥3+4 和≥4+4 疾病。使用椭圆计算（TVe）和半自动分割（TVs）确定前列腺总体积，并使用组内相关系数（ICC）评估观察者间可靠性。为 TVe 和 TVs 计算 PSAd，并绘制 ROC 曲线以比较 Gleason≥3+4 和≥4+4 疾病的性能。
TVe 明显高于 TVs（p<0.0001），平均 TVe=55.4ml，TVs=51.0ml。使用 TVe（0.63，95%CI：0.59-0.68）和 TVs（0.64，95%CI：0.59-0.68）计算得出的 PSAd 的 ROC 曲线下面积对于 Gleason≥3+4 疾病没有显著差异（p=0.45），但对于 Gleason≥4+4 疾病，使用 TVs（0.63，95%CI：0.58-0.68）计算得出的 PSAd 明显优于 TVe（0.61，95%CI：0.57-0.67）（p=0.02）。两种方法的 TVe 的观察者间可靠性均非常出色，ICC 为 0.93（95%CI：0.92-0.94），而 TVs 的 ICC 为 0.98（95%CI：0.98-0.99）。
与分割相比，传统的椭圆测量方法往往会高估总前列腺体积，但这两种方法在 PI-RADS 临床显著疾病中都显示出 PSA 密度的相似诊断性能。对于更高等级的疾病，源自分割体积的 PSAd 表现出统计学上显著的优越性能。这两种方法都是可行的，但分割体积可能更好。
