Faranesh Anthony Z, Kraitchman Dara L, McVeigh Elliot R
Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA.
Magn Reson Med. 2006 May;55(5):1114-23. doi: 10.1002/mrm.20884.
The purpose of this work was to investigate the use of an intravascular contrast agent to determine perfusion kinetics in skeletal muscle. A two-compartment kinetic model was used to represent the flux of contrast agent between the intravascular space and extravascular extracellular space (EES). The relationship between the image signal-to-noise ratio (SNR) and errors in estimating permeability surface area product (Ktrans), interstitial volume (ve), and plasma volume (vp) for linear and nonlinear curve-fitting methods was estimated from Monte Carlo simulations. Similar results were obtained for both methods. For an image SNR of 60, the estimated errors in these parameters were 10%, 22%, and 17%, respectively. In vivo experiments were conducted in rabbits to examine physiological differences between these parameters in the soleus (SOL) and tibialis anterior (TA) muscles in the hind limb. Values for Ktrans were significantly higher in the SOL (3.2+/-0.9 vs. 2.0+/-0.5x10(-3) min-1), as were values for vp (3.4+/-0.8 vs. 2.1+/-0.7%). Differences in ve for the two muscles (8.7+/-2.2 vs. 8.5+/-1.6%) were not found to be significant. These results demonstrate that relevant physiological metrics can be calculated in skeletal muscle using MRI with an intravascular contrast agent.
这项工作的目的是研究使用血管内造影剂来确定骨骼肌的灌注动力学。采用双室动力学模型来表示造影剂在血管内空间和血管外细胞外间隙（EES）之间的通量。通过蒙特卡罗模拟估计了线性和非线性曲线拟合方法下图像信噪比（SNR）与估计通透表面积乘积（Ktrans）、组织间隙容积（ve）和血浆容积（vp）误差之间的关系。两种方法得到了相似的结果。对于图像SNR为60的情况，这些参数的估计误差分别为10%、22%和17%。在兔体内进行实验，以研究后肢比目鱼肌（SOL）和胫前肌（TA）中这些参数的生理差异。SOL中的Ktrans值显著更高（3.2±0.9 vs. 2.0±0.5×10⁻³ min⁻¹），vp值也是如此（3.4±0.8 vs. 2.1±0.7%）。未发现这两块肌肉的ve差异（8.7±2.2 vs. 8.5±1.6%）具有显著性。这些结果表明，使用血管内造影剂的MRI可以计算骨骼肌中的相关生理指标。
