Hanoï Medical University Hospital, Dong Da, Hanoi, Viet Nam.
Université Grenoble Alpes, Laboratoire d'Ecologie Alpine, Grenoble 38041, France; CNRS, UMR 5553, Grenoble, 38041, France.
Diagn Interv Imaging. 2022 Nov;103(11):545-554. doi: 10.1016/j.diii.2022.06.001. Epub 2022 Jun 27.
The purpose of this study was to quantify the influence of factors of variability on apparent diffusion coefficient (ADC) estimation in the normal prostate peripheral zone (PZ).
Fifty healthy volunteers underwent in 2017 (n = 17) or 2020 (n = 33) two-point (0, 800 s/mm²) prostate diffusion-weighted imaging in the morning on 1.5 T scanners A and B from different manufacturers. Additional five-point (50, 150, 300, 500, 800 s/mm²) acquisitions were performed on scanner B in the morning and evening. ADC was measured in PZ at midgland using ADC maps reconstructed with various b-value combinations. ADC distributions from 2017 and 2020 were compared using Wilcoxon rank sum test. ADC obtained in the same volunteers were compared using Bland Altman methodology. The 95% confidence interval upper limit of the repeatability/reproducibility coefficient defined the lowest detectable ADC difference.
Forty-nine participants with a mean age of 24.6 ± 3.8 [SD] years (range: 21-37 years) were finally included. ADC distributions from 2017 and 2020 were not significantly different and were combined. Despite high individual variability, there was no significant bias (10 × 10 mm²/s, P = 0.58) between ADC measurements made on both scanners. On scanner B, differences in lowest b-values chosen within the 0-500 s/mm² range for two-point ADC computation induced significant biases (56-109 × 10 mm²/s, P < 0.0001). ADC was significantly lower in the morning (bias: 33 × 10 mm²/s, P = 0.006). The number of b-values had little influence on ADC values. The lowest detectable ADC difference varied from 85 × 10 to 311 × 10 mm²/s across scanners, b-value combinations and periods of the day.
The MRI scanner, the lowest b-value used and the period of the day induce substantial variability in ADC computation.
本研究旨在量化各种变异性因素对正常前列腺外周带（PZ）表观扩散系数（ADC）估计的影响。
2017 年（n=17）或 2020 年（n=33），50 名健康志愿者分别在上午使用来自不同制造商的 1.5T 扫描仪 A 和 B 进行两点（0、800 s/mm²）前列腺弥散加权成像。在扫描仪 B 上，上午和晚上还进行了五点（50、150、300、500、800 s/mm²）采集。使用各种 b 值组合重建 ADC 图，在中叶测量 PZ 中的 ADC。使用 Wilcoxon 秩和检验比较 2017 年和 2020 年的 ADC 分布。使用 Bland-Altman 方法比较同一志愿者的 ADC。重复性/再现性系数的 95%置信区间上限定义了可检测到的最低 ADC 差异。
最终纳入 49 名年龄 24.6±3.8 岁（21-37 岁）的志愿者。2017 年和 2020 年的 ADC 分布无显著差异，因此将两者结合。尽管个体间存在高度变异性，但两台扫描仪上的 ADC 测量值之间没有显著偏差（10×10 mm²/s，P=0.58）。在扫描仪 B 上，用于计算两点 ADC 的最低 b 值在 0-500 s/mm² 范围内的选择差异导致了显著的偏差（56-109×10 mm²/s，P<0.0001）。上午的 ADC 明显较低（偏差：33×10 mm²/s，P=0.006）。b 值的数量对 ADC 值的影响很小。在不同的扫描仪、b 值组合和一天中的不同时间段，可检测到的最低 ADC 差异从 85×10 到 311×10 mm²/s 不等。
MRI 扫描仪、使用的最低 b 值和一天中的时段会导致 ADC 计算产生显著的变异性。
