van der Velden Bas H M, van Rijssel Michael J, Lena Beatrice, Philippens Marielle E P, Loo Claudette E, Ragusi Max A A, Elias Sjoerd G, Sutton Elizabeth J, Morris Elizabeth A, Bartels Lambertus W, Gilhuijs Kenneth G A
Image Sciences Institute, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
Department of Radiotherapy, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
J Magn Reson Imaging. 2020 Nov;52(5):1374-1382. doi: 10.1002/jmri.27244. Epub 2020 Jun 3.
Differences in imaging parameters influence computer-extracted parenchymal enhancement measures from breast MRI.
To investigate the effect of differences in dynamic contrast-enhanced MRI acquisition parameter settings on quantitative parenchymal enhancement of the breast, and to evaluate harmonization of contrast-enhancement values with respect to flip angle and repetition time.
Retrospective.
PHANTOM/POPULATIONS: We modeled parenchymal enhancement using simulations, a phantom, and two cohorts (N = 398 and N = 302) from independent cancer centers.
SEQUENCE FIELD/STRENGTH: 1.5T dynamic contrast-enhanced T -weighted spoiled gradient echo MRI. Vendors: Philips, Siemens, General Electric Medical Systems.
We assessed harmonization of parenchymal enhancement in simulations and phantom by varying the MR parameters that influence the amount of T -weighting: flip angle (8°-25°) and repetition time (4-12 msec). We calculated the median and interquartile range (IQR) of the enhancement values before and after harmonization. In vivo, we assessed overlap of quantitative parenchymal enhancement in the cohorts before and after harmonization using kernel density estimations. Cohort 1 was scanned with flip angle 20° and repetition time 8 msec; cohort 2 with flip angle 10° and repetition time 6 msec.
Paired Wilcoxon signed-rank-test of bootstrapped kernel density estimations.
Before harmonization, simulated enhancement values had a median (IQR) of 0.46 (0.34-0.49). After harmonization, the IQR was reduced: median (IQR): 0.44 (0.44-0.45). In the phantom, the IQR also decreased, median (IQR): 0.96 (0.59-1.22) before harmonization, 0.96 (0.91-1.02) after harmonization. Harmonization yielded significantly (P < 0.001) better overlap in parenchymal enhancement between the cohorts: median (IQR) was 0.46 (0.37-0.58) for cohort 1 vs. 0.37 (0.30-0.44) for cohort 2 before harmonization (57% overlap); and 0.35 (0.28-0.43) vs. .0.37 (0.30-0.44) after harmonization (85% overlap).
The proposed practical harmonization method enables an accurate comparison between patients scanned with differences in imaging parameters.
3 TECHNICAL EFFICACY STAGE: 4.
成像参数的差异会影响从乳腺MRI计算机提取的实质增强测量值。
研究动态对比增强MRI采集参数设置的差异对乳腺实质定量增强的影响，并评估对比增强值在翻转角和重复时间方面的一致性。
回顾性研究。
模型/人群：我们使用模拟、模型以及来自独立癌症中心的两个队列（N = 398和N = 302）对实质增强进行建模。
1.5T动态对比增强T加权扰相梯度回波MRI。供应商：飞利浦、西门子、通用电气医疗系统公司。
我们通过改变影响T加权量的MR参数（翻转角（8°-25°）和重复时间（4-12毫秒））来评估模拟和模型中实质增强的一致性。我们计算了一致性前后增强值的中位数和四分位间距（IQR）。在体内，我们使用核密度估计评估了一致性前后队列中定量实质增强的重叠情况。队列1采用翻转角20°和重复时间8毫秒进行扫描；队列2采用翻转角10°和重复时间6毫秒进行扫描。
对自展核密度估计进行配对Wilcoxon符号秩检验。
在一致性之前，模拟增强值的中位数（IQR）为0.46（0.34-0.49）。一致性之后，IQR降低：中位数（IQR）：0.44（0.44-0.45）。在模型中，IQR也降低了，一致性之前中位数（IQR）：0.96（0.59-1.22），一致性之后为0.96（0.91-1.02）。一致性使队列之间实质增强的重叠显著更好（P < 0.001）：一致性之前，队列1的中位数（IQR）为0.46（0.37-0.58），队列2为0.37（0.30-0.44）（重叠57%）；一致性之后为0.35（0.28-0.43）对0.37（0.30-0.44）（重叠85%）。
所提出的实用一致性方法能够对成像参数不同的扫描患者进行准确比较。
3 技术效能阶段：4。
