巴马猪颈动脉HR-MRI重复扫描与TRICKS初步研究

Reproducibility of contrast-enhanced high-resolution magnetic resonance imaging of carotid artery of Bama mini pig

目的定量计算巴马小型猪颈动脉多序列HR-MRI重复扫描的一致性,并利用TRICKS技术观察巴马小型猪颈部血管的动态强化特征。方法运用3 T MRI仪对3只健康的巴马小型猪颈部血管进行扫描,定位序列为2D TOF MRA,HR-MRI包括3D TOF MRA、2D FSE FS的T_2WI和T_1WI,然后行TRICKS,最后是2D FSE FS T_1WI增强扫描。两周后重复上述扫描。定量分析两次HR-MRI扫描的T_2WI、T_1WI及T_1WI增强序列的血管总面积、管腔面积和管壁面积的组内和组间的一致性。观察TRICKS序列颈部血管解剖和动态强化表现。结果 HR-MRI重复扫描的分析发现T_1WI增强(CV<15%)和T_1WI平扫(ICC>0.75)的一致性较好;观察者内的分析显示各序列的一致性均非常好(ICC>0.75),且T_1WI增强的一致性最佳(ICC>0.80);观察者间的分析表明各序列的一致性均非常好(CV<15%,ICC>0.75)。TRICKS显示注射对比剂后第5期(24～30 s)颈总动脉系统显影最佳。结论巴马小型猪的颈部动脉适于HR-MRI成像,本研究的HR-MRI技术对巴马小型猪颈动脉管壁成像的重复扫描的一致性良好,可用于管壁病变的定量研究。

Objective To evaluate the scan-rescan reproducibility o f multiple contrast-enhanced （CE） high-resolution magnetic resonance imaging （HR-MRI） of carotid artery of Bama mini pig, and to observe the dynamic enhancement feature of cervical vessels. Methods The cervical vessels o f three healthy Bama mini pigs were scanned twice at 2-week interval using a 3 T MR system. The scan protocol included 2-D time-of-flight （TOF） MR angiography （MRA） for positioning, 3-D TOF MR A, 2-D fat-saturated （FS） fast spin-echo （FSE） T2-weighted imaging （T2WI） and Ti-weighted imaging （TxWI） for HR-MRI, time-resolved imaging of contrast kinetics （TRICKS） MRA and CE 2-D FS FSE TiWI. Areas of total vessel, lumen and vessel wall of the carotid artery on T2WI,TiWT and CE TiWI of HR-MRI were quantified and compared between two repeated scans to determine the intraobserver and inteiobserver agreement. The anatomical structure and dynamic enhancement of cervical vessels on TRICKS were observed as well. Results For interscan analysis, CE TiWI （CV〈15%） and T1WI （ICG〉0.75） showed good agreement. For intraobserver analysis, every sequence showed good agreement （ICC〉0.75）, and CE T1WI had excellent agreement （ICC〉0.80）. For interobserver analysis, every sequence showed good agreement （CV〈15%, ICC〉0.75）. The common carotid artery was optimally delineated at 24 -30 s after contrast agent injection on TRICKS. Conclusion The carotid artery wall of Bama mini pig can be optimally depicted on HR-MRI with good reproducibility for quantitative study of vessel wall lesions.