Liu Mira M, Dyke Jonathan, Gladytz Thomas, Jasse Jonas, Bolger Ian, Calle Sergio, Pavaluri Swathi, Crews Tanner, Seshan Surya, Salvatore Steven, Stillman Isaac, Muthukumar Thangamani, Taouli Bachir, Farouk Samira, Lewis Sara, Bane Octavia
BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
Department of Radiology/Citigroup Biomedical Imaging Center, Weill Cornell Medicine, New York, NY, USA.
ArXiv. 2024 Aug 12:arXiv:2408.06427v1.
Estimation of multi-compartment intravoxel 'flow' in in ml/100g/min with multi-b-value diffusion weighted imaging and a multi-Gaussian model in the kidneys.
A multi-Gaussian model of intravoxel flow using water transport time to quantify (ml/100g/min) is presented and simulated. Multi-compartment anisotropic DWI signal is simulated with Rician noise and SNR=50 and analyzed with a rigid bi-exponential, a rigid tri-exponential and diffusion spectrum imaging model of intravoxel incoherent motion (spectral diffusion) to study extraction of multi-compartment flow. The regularization parameter for spectral diffusion is varied to study the impact on the resulting spectrum and computation speed. The application is demonstrated in a two-center study of 54 kidney allografts with 9 b-value advanced DWI that were split by function (CKD-EPI 2021 eGFR<45ml/min/1.73m) and fibrosis (Banff 2017 interstitial fibrosis and tubular atrophy score 0-6) to demonstrate multi-compartment flow of various kidney pathologies.
Simulation of anisotropic multi-compartment flow from spectral diffusion demonstrated strong correlation to truth for both three-compartment anisotropic diffusion ( ) and two-compartment anisotropic diffusion ( ), outperforming rigid models in cases of variable compartment number. Use of a fixed regularization parameter set to increased computation up to 208-fold and agreed with voxel-wise cross-validated regularization (concordance correlation coefficient=0.99). Spectral diffusion of renal allografts showed decreasing trend of tubular and vascular flow with higher levels of fibrosis, and significant increase in tissue parenchyma flow (f-stat=3.86, p=0.02). Tubular was significantly decreased in allografts with impaired function (eGFR<45ml/min/1.73m)(Mann-Whitney U t-stat=-2.14, p=0.04).
Quantitative multi-compartment intravoxel 'flow' can be estimated in ml/100g/min with from multi-Gaussian diffusion with water transport time, even with moderate anisotropy such as in kidneys. The use of spectral diffusion with a multi-Gaussian model and a fixed regularization parameter is particularly promising in organs such as the kidney with variable numbers of physiologic compartments.
利用多b值扩散加权成像和多高斯模型，以毫升/100克/分钟为单位估计肾脏内多室体素“血流”。
提出并模拟了一种利用水传输时间量化（毫升/100克/分钟）的体素内血流多高斯模型。使用莱斯噪声和信噪比=50模拟多室各向异性扩散加权成像（DWI）信号，并采用刚性双指数、刚性三指数和体素内不相干运动（谱扩散）的扩散谱成像模型进行分析，以研究多室血流的提取。改变谱扩散的正则化参数，以研究其对所得谱和计算速度的影响。在一项针对54例肾移植受者的双中心研究中进行了应用展示，这些肾移植受者接受了具有9个b值的高级DWI检查，并根据功能（慢性肾脏病流行病学协作组[CKD-EPI]2021年估算肾小球滤过率[eGFR]<45毫升/分钟/1.73平方米）和纤维化程度（2017年班夫间质纤维化和肾小管萎缩评分0 - 6）进行分组，以展示各种肾脏病理状态下的多室血流情况。
谱扩散各向异性多室血流模拟结果显示，三室各向异性扩散（ ）和两室各向异性扩散（ ）与真实情况均具有很强的相关性，在室数量可变的情况下优于刚性模型。使用固定正则化参数设置为 可使计算量增加至208倍，并与体素级交叉验证正则化结果一致（一致性相关系数=0.99）。肾移植受者的谱扩散显示，随着纤维化程度升高，肾小管和血管血流呈下降趋势，组织实质血流显著增加（F检验值=3.86，p=0.02）。功能受损（eGFR<45毫升/分钟/1.73平方米）的肾移植受者肾小管 显著降低（曼-惠特尼U检验t值=-2.14，p=0.04）。
即使在肾脏等具有中等各向异性的器官中，利用水传输时间的多高斯扩散，也能够以毫升/100克/分钟为单位估计定量多室体素“血流”。在肾脏等具有可变生理室数量的器官中，使用具有多高斯模型和固定正则化参数的谱扩散方法尤其具有前景。
