Wang Yuenan, Booth Carmen J, Kim Hyeonjin, Qiu Maolin, Constable R Todd
Biomedical Engineering, Yale University, New Haven, CT 06520-8043, USA.
Magn Reson Med. 2009 May;61(5):1185-92. doi: 10.1002/mrm.21964.
MRI has the potential of providing a noninvasive assessment of liver pathology. This work introduces a portal pressure gradient (PPG) model derived from fluid mechanics, where the PPG is proportional to the average velocity and inversely proportional to the vessel area in the upper part of portal vein. Using a phase-contrast spoiled gradient echo sequence, the PPG model was verified in a phantom study and was tested in an animal study using 35 rats with various degrees of hepatic fibrosis induced by carbon tetrachloride (CCl(4)). Histological examination was conducted to determine the severity of hepatic fibrosis. The fibrosis score monotonically increased with the duration of CCl(4) treatment. The PPG was highly correlated with nonzero fibrosis scores (r(2) = 0.90, P < 0.05). There was a significant difference between control and cirrhosis groups (P < 0.0006, alpha < 0.0018). The difference between control and fibrosis (noncirrhosis) groups (P < 0.002, alpha < 0.006) was also significant. Without the administration of any contrast agent, the MRI-PPG approach shows promise as a noninvasive means of evaluating liver fibrosis.
磁共振成像（MRI）有潜力对肝脏病变进行无创评估。这项研究引入了一种基于流体力学的门静脉压力梯度（PPG）模型，其中PPG与门静脉上部的平均流速成正比，与血管面积成反比。使用相位对比扰相梯度回波序列，该PPG模型在体模研究中得到验证，并在一项动物研究中对35只由四氯化碳（CCl₄）诱导产生不同程度肝纤维化的大鼠进行了测试。进行组织学检查以确定肝纤维化的严重程度。纤维化评分随CCl₄处理时间的延长而单调增加。PPG与非零纤维化评分高度相关（r² = 0.90，P < 0.05）。对照组与肝硬化组之间存在显著差异（P < 0.0006，α < 0.0018）。对照组与纤维化（非肝硬化）组之间的差异（P < 0.002，α < 0.006）也很显著。无需使用任何造影剂，MRI-PPG方法有望成为评估肝纤维化的一种无创手段。
