Simeth Josiah, Johansson Adam, Owen Dawn, Cuneo Kyle, Mierzwa Michelle, Feng Mary, Lawrence Theodore S, Cao Yue
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
NMR Biomed. 2018 Jun;31(6):e3913. doi: 10.1002/nbm.3913. Epub 2018 Apr 19.
Dynamic gadoxetic acid-enhanced magnetic resonance imaging (MRI) allows the investigation of liver function through the observation of the perfusion and uptake of contrast agent in the parenchyma. Voxel-by-voxel quantification of the contrast uptake rate (k ) from dynamic gadoxetic acid-enhanced MRI through the standard dual-input, two-compartment model could be susceptible to overfitting of variance in the data. The aim of this study was to develop a linearized, but more robust, model. To evaluate the estimated k values using this linearized analysis, high-temporal-resolution gadoxetic acid-enhanced MRI scans were obtained in 13 examinations, and k maps were created using both models. Comparison of liver k values estimated from the two methods produced a median correlation coefficient of 0.91 across the 12 scans that could be used. Temporally sparse clinical MRI data with gadoxetic acid uptake were also employed to create k maps of 27 examinations using the linearized model. Of 20 scans, the created k maps were compared with overall liver function as measured by indocyanine green (ICG) retention, and yielded a correlation coefficient of 0.72. In the 27 k maps created via the linearized model, the mean liver k value was 3.93 ± 1.79 mL/100 mL/min, consistent with previous studies. The results indicate that the linearized model provides a simple and robust method for the assessment of the rate of contrast uptake that can be applied to both high-temporal-resolution dynamic contrast-enhanced MRI and typical clinical multiphase MRI data, and that correlates well with the results of both two-compartment analysis and independent whole liver function measurements.
动态钆塞酸增强磁共振成像（MRI）可通过观察造影剂在肝实质中的灌注和摄取来研究肝功能。通过标准双输入双室模型对动态钆塞酸增强MRI的造影剂摄取率（k）进行逐体素定量可能容易受到数据方差过拟合的影响。本研究的目的是开发一种线性化但更稳健的模型。为了使用这种线性化分析评估估计的k值，在13次检查中获得了高时间分辨率的钆塞酸增强MRI扫描，并使用两种模型创建了k图。在12次可用扫描中，两种方法估计的肝脏k值比较产生的中位数相关系数为0.91。还采用了具有钆塞酸摄取的时间稀疏临床MRI数据，使用线性化模型创建了27次检查的k图。在20次扫描中，将创建的k图与通过吲哚菁绿（ICG）滞留测量的整体肝功能进行比较，相关系数为0.72。在通过线性化模型创建的27个k图中，肝脏平均k值为3.93±1.79 mL/100 mL/min，与先前研究一致。结果表明，线性化模型为评估造影剂摄取率提供了一种简单且稳健的方法，可应用于高时间分辨率动态对比增强MRI和典型临床多期MRI数据，并且与双室分析结果和独立的全肝功能测量结果都具有良好的相关性。
