Department of Radiology, University of Alabama, Birmingham, AL, 35294, USA.
Alliance for Innovative Medical Technology, Southern Research, Birmingham, AL, 35205, USA.
Med Phys. 2017 Oct;44(10):5198-5209. doi: 10.1002/mp.12466. Epub 2017 Aug 12.
The aim of this study was to develop a portable perfusion phantom and validate its utility in quantitative dynamic contrast-enhanced magnetic resonance imaging of the abdomen.
A portable perfusion phantom yielding a reproducible contrast enhancement curve (CEC) was developed. A phantom package including perfusion and static phantoms were imaged simultaneously with each of three healthy human volunteers in two different 3T MR scanners. Look-up tables correlating reference (known) contrast concentrations with measured ones were created using either the static or perfusion phantom. Contrast maps of image slices showing four organs (liver, spleen, pancreas, and paravertebral muscle) were generated before and after data correction using the look-up tables. The contrast concentrations at 4.5 min after dosing in each of the four organs were averaged for each volunteer. The mean contrast concentrations (4 organs × 3 volunteers = 12) were compared for the two scanners, and the intra-class correlation coefficient (ICC) was calculated. Also, the ICC of the mean K values between the two scanners was calculated before and after data correction.
The repeatability coefficient of CECs of perfusion phantom was higher than 0.997 in all measurements. The ICC of the tissue contrast concentrations between the two scanners was 0.693 before correction, but increased to 0.974 after correction using the look-up tables (LUTs) of perfusion phantom. However, the ICC was not increased after correction using static phantom (ICC: 0.617). Similarly, the ICC of the K values was 0.899 before correction, but increased to 0.996 after correction using perfusion phantom LUTs. The ICC of the K values, however, was not increased when static phantom LUTs were used (ICC: 0.866).
The perfusion phantom reduced variability in quantitating contrast concentration and K values of human abdominal tissues across different MR units, but static phantom did not. The perfusion phantom has the potential to facilitate multi-institutional clinical trials employing quantitative DCE-MRI to evaluate various abdominal malignancies.
本研究旨在开发一种便携式灌注体模，并验证其在腹部定量动态对比增强磁共振成像中的效用。
开发了一种可产生重现性对比增强曲线（CEC）的便携式灌注体模。使用三种健康志愿者，在两台不同的 3T 磁共振扫描仪中，同时对灌注和静态体模进行成像。使用静态或灌注体模创建参考（已知）对比浓度与测量浓度之间的查找表。使用查找表校正数据前后，生成显示四个器官（肝、脾、胰腺和椎旁肌肉）的图像切片的对比图。在每个志愿者中，在给药后 4.5 分钟测量每个器官的平均对比浓度。比较两台扫描仪的四个器官的平均对比浓度（4 个器官×3 个志愿者=12），并计算组内相关系数（ICC）。此外，还分别计算校正前后两个扫描仪之间平均 K 值的 ICC。
在所有测量中，灌注体模 CEC 的重复性系数均高于 0.997。校正前，两台扫描仪之间组织对比浓度的 ICC 为 0.693，但使用灌注体模的查找表（LUT）校正后增加至 0.974。然而，使用静态体模校正后 ICC 并未增加（ICC：0.617）。同样，校正前 K 值的 ICC 为 0.899，但使用灌注体模 LUT 校正后增加至 0.996。然而，使用静态体模 LUT 时，K 值的 ICC 并未增加（ICC：0.866）。
与静态体模相比，灌注体模降低了不同磁共振设备定量评估人体腹部组织对比浓度和 K 值的变异性。灌注体模有可能促进采用定量 DCE-MRI 评估各种腹部恶性肿瘤的多机构临床试验。
