Hormuth David A, Skinner Jack T, Does Mark D, Yankeelov Thomas E
Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA.
Magn Reson Imaging. 2014 May;32(4):397-401. doi: 10.1016/j.mri.2013.12.019. Epub 2014 Jan 7.
Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can quantitatively and qualitatively assess physiological characteristics of tissue. Quantitative DCE-MRI requires an estimate of the time rate of change of the concentration of the contrast agent in the blood plasma, the vascular input function (VIF). Measuring the VIF in small animals is notoriously difficult as it requires high temporal resolution images limiting the achievable number of slices, field-of-view, spatial resolution, and signal-to-noise. Alternatively, a population-averaged VIF could be used to mitigate the acquisition demands in studies aimed to investigate, for example, tumor vascular characteristics. Thus, the overall goal of this manuscript is to determine how the kinetic parameters estimated by a population based VIF differ from those estimated by an individual VIF. Eight rats bearing gliomas were imaged before, during, and after an injection of Gd-DTPA. K(trans), ve, and vp were extracted from signal-time curves of tumor tissue using both individual and population-averaged VIFs. Extended model voxel estimates of K(trans) and ve in all animals had concordance correlation coefficients (CCC) ranging from 0.69 to 0.98 and Pearson correlation coefficients (PCC) ranging from 0.70 to 0.99. Additionally, standard model estimates resulted in CCCs ranging from 0.81 to 0.99 and PCCs ranging from 0.98 to 1.00, supporting the use of a population based VIF if an individual VIF is not available.
动态对比增强磁共振成像（DCE-MRI）可以定量和定性地评估组织的生理特征。定量DCE-MRI需要估计血浆中造影剂浓度的时间变化率，即血管输入函数（VIF）。在小动物中测量VIF非常困难，因为它需要高时间分辨率的图像，这限制了可实现的切片数量、视野、空间分辨率和信噪比。另外，在旨在研究例如肿瘤血管特征的研究中，可以使用群体平均VIF来减轻采集需求。因此，本手稿的总体目标是确定基于群体的VIF估计的动力学参数与个体VIF估计的动力学参数有何不同。八只患有神经胶质瘤的大鼠在注射钆喷酸葡胺之前、期间和之后进行了成像。使用个体和群体平均VIF从肿瘤组织的信号-时间曲线中提取K(trans)、ve和vp。所有动物中K(trans)和ve的扩展模型体素估计的一致性相关系数（CCC）范围为0.69至0.98，皮尔逊相关系数（PCC）范围为0.70至0.99。此外，标准模型估计的CCC范围为0.81至0.99，PCC范围为0.98至1.00，这支持在没有个体VIF的情况下使用基于群体的VIF。
