Section on Tissue Biophysics and Biomimetics, Program on Pediatric Imaging and Tissue Science, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Magn Reson Chem. 2011 Dec;49 Suppl 1(Suppl 1):S79-84. doi: 10.1002/mrc.2797.
Measurement of diffusion in porous materials and biological tissues with the pulsed field gradient (PFG) MR techniques has proven useful in characterizing the microstructure of such specimens noninvasively. A natural extension of the traditional PFG technique comprises multiple pairs of diffusion gradients. This approach has been shown to provide the ability to characterize anisotropy at different length scales without the need to employ very strong gradients. In this work, the double-PFG imaging technique was used on a specimen involving a series of glass capillary arrays with different diameters. The experiments on the phantom demonstrated the ability to create a quantitative and accurate map of pore sizes. The same technique was subsequently employed to image a celery stalk. A diffusion tensor image (DTI) of the same specimen was instrumental in accurately delineating the regions of vascular tissue and determining the local orientation of cells. This orientation information was incorporated into a theoretical double-PFG framework and the technique was employed to estimate the cell size in the vascular bundles of the celery stalk. The findings suggest that the double-PFG MRI framework could provide important new information regarding the microstructure of many plants and other food products.
使用脉冲梯度（PFG）MR 技术测量多孔材料和生物组织中的扩散已被证明可用于无创地描述此类样本的微观结构。传统 PFG 技术的自然扩展包括多对扩散梯度。这种方法已被证明具有在不同尺度上表征各向异性的能力，而无需使用非常强的梯度。在这项工作中，双 PFG 成像技术用于涉及一系列不同直径玻璃毛细管阵列的样本。在该模型上的实验证明了创建孔径定量且精确图谱的能力。随后，相同的技术被用于对芹菜茎进行成像。同一样本的扩散张量图像（DTI）有助于准确描绘血管组织区域并确定细胞的局部方向。将该方向信息纳入理论双 PFG 框架，并使用该技术估计芹菜茎血管束中的细胞大小。研究结果表明，双 PFG MRI 框架可以为许多植物和其他食品产品的微观结构提供重要的新信息。
