Stabinska Julia, Thiel Thomas A, Wittsack Hans-Jörg, Ljimani Alexandra, Zöllner Helge J
F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States.
Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.
medRxiv. 2025 Jul 15:2025.07.14.25331475. doi: 10.1101/2025.07.14.25331475.
To quantitatively assess the bias in the intravoxel incoherent motions (IVIM)-derived pseudo-diffusion volume fraction () caused by the differences in relaxation times between the tissue and fluid compartments, and to develop a 2D fitting approach and an optimal acquisition protocol for the relaxation compensated T2-IVIM imaging in the liver and kidney.
Numerical simulations were conducted to investigate the TR- and TE-dependent bias in when using the conventional IVIM model, and to evaluate the applicability of the extended 2D T2-IVIM model for reducing this bias. The findings were then validated using the IVIM data from healthy volunteers on a clinical 3-Tesla MRI scanner. Finally, a numerical framework for optimizing the T2-IVIM protocol for relaxation-compensated parameter estimation was proposed and tested using data.
When using the traditional IVIM model, a trend toward higher with increasing TE was found in the liver (R = 0.42, P = 0.043), but not in the kidney cortex (R = -0.067, P = 0.76) and medulla (R = 0.039, P = 0.86). The 2D T2-IVIM modeling yielded lower and reduced the intra-subject variability in the liver. Our results also suggest that a b-TE protocol with six b-values and three different TE values (50, 55, and 100 ms) might be optimal for liver T2-IVIM.
The extended 2D T2-IVIM model combined effectively minimizes the TE-dependent bias in and allows simultaneous estimation of the IVIM parameter and compartmental T2 values in the liver and kidney.
定量评估体素内不相干运动（IVIM）衍生的伪扩散容积分数（）因组织和液体成分弛豫时间差异而产生的偏差，并为肝脏和肾脏的弛豫补偿T2-IVIM成像开发二维拟合方法和最佳采集方案。
进行数值模拟，以研究使用传统IVIM模型时，与TR和TE相关的偏差，并评估扩展的二维T2-IVIM模型减少这种偏差的适用性。然后使用临床3特斯拉MRI扫描仪上健康志愿者的IVIM数据验证研究结果。最后，提出了一个用于优化T2-IVIM方案以进行弛豫补偿参数估计的数值框架，并使用数据进行了测试。
使用传统IVIM模型时，在肝脏中发现随着TE增加而有升高的趋势（R = 0.42，P = 0.043），但在肾皮质（R = -0.067，P = 0.76）和髓质（R = 0.039, P = 0.86）中未发现此趋势。二维T2-IVIM建模在肝脏中产生了较低的，并降低了个体内变异性。我们的结果还表明，具有六个b值和三个不同TE值（50、55和100毫秒）的b-TE方案可能是肝脏T2-IVIM的最佳方案。
扩展的二维T2-IVIM模型有效组合可最大程度减少与TE相关的偏差，并允许同时估计肝脏和肾脏中的IVIM参数和成分T2值。
