The Research Institute and Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.
Magn Reson Med. 2010 Dec;64(6):1772-80. doi: 10.1002/mrm.22573. Epub 2010 Aug 16.
Dynamic contrast-enhanced MRI has been used in conjunction with tracer kinetics modeling in a wide range of tissues for treatment monitoring, oncology drug development, and investigation of disease processes. Accurate measurement of model parameters relies on acquiring data with high temporal resolution and low noise, particularly for models with large numbers of free parameters, such as the adiabatic approximation to the tissue homogeneity model for separate measurements of blood flow and vessel permeability. In this simulation study, accuracy of the adiabatic approximation to the tissue homogeneity model was investigated, examining the effects of temporal resolution, noise levels, and error in the measured arterial input function. A temporal resolution of 1.5 s and high SNR (noise sd = 0.05) were found to ensure minimal bias (<5%) in all four model parameters (extraction fraction, blood flow, mean transit time, and extravascular extracellular volume), and the sampling interval can be relaxed to 6 s, if the transit time need not be measured accurately (bias becomes >10%). A 10% error in the measured height of the arterial input function first pass peak resulted in an error of at most 10% in each model parameter.
动态对比增强 MRI 已与示踪剂动力学模型结合，广泛应用于治疗监测、肿瘤药物开发和疾病过程研究等领域。模型参数的准确测量依赖于具有高时间分辨率和低噪声的数据采集，特别是对于具有大量自由参数的模型，例如用于分别测量血流和血管通透性的组织均匀性模型的绝热近似。在这项模拟研究中，我们研究了组织均匀性模型的绝热近似的准确性，考察了时间分辨率、噪声水平和测量的动脉输入函数误差的影响。结果发现，时间分辨率为 1.5 秒和高 SNR（噪声 sd = 0.05）可确保所有四个模型参数（提取分数、血流、平均通过时间和细胞外间隙体积）的偏差最小（<5%），如果不需要准确测量通过时间（偏差超过 10%），采样间隔可以放宽到 6 秒。测量的动脉输入函数首过峰值高度的 10%误差导致每个模型参数的误差最大不超过 10%。
