正常兔膝关节的三维UTE动态增强MRI实验研究

The experimental study of the 3D-UTE dynamic enhanced MRI in the normal rabbit knee joint

目的:探讨三维超短回波时间(UTE)双回波脉冲序列在主要含短T2成分组织的动态增强MRI中的应用。方法:采用随机数字对照表对6只新西兰大白兔的6个膝关节行MR平扫及UTE动态增强检查。分析正常兔的髌韧带、股骨下段或胫骨上段骨皮质、髓腔的动态增强特点,并与病理结果对照。采用t检验比较未成年兔与成年兔骨皮质的中央管计数。结果:正常兔髌韧带的UTE动态增强信号强度-时间曲线表现为缓慢上升型。未成年兔骨皮质动态增强曲线表现为缓慢上升至峰值时,稍有下降后维持于较高水平;成年兔骨皮质UTE动态增强特点表现为速升速降型。成年兔与未成年兔髓腔的UTE动态增强特点均表现为速升缓降型,组织内对比剂浓度持续较高水平。骨皮质的动态增强曲线差异与组织学所见基本匹配。结论:三维UTE双回波脉冲序列成像可用于主要含短T2成分组织的动态增强检查。

Objective：To investigate the application of 3D-ultrashort TE （3D-UTE）sequence in the dynamic enhanced MRI of the tissues containing majority of short T2 components.Methods：Plain scan and dynamic enhanced MRI with 3D ultrashort TE double echo pulse sequence were performed on 6 knee joints of 6 New Zealand white rabbits according to random digital comparison table.The characteristics of the dynamic enhanced MRI of the patellar ligament,the cortical bone and the bone marrow of the lower segment of the femur and the upper segment of tibia were investigated and compared with the histologic findings.To compare the central canal count of young and adult rabbits with t test.Results：The signal intensity-time curves of the dynamic enhanced MRI of the patellar ligament of the normal rabbits appeared as gradual slope of enhancement.The dynamic curve of the bone cortex of the young rabbits appeared as gradual slope of enhancement and slow washout pattern.The dynamic curve of the bone cortex of the adult rabbits appeared as fast increase of enhancement and fast washout pattern.The dynamic curve of the bone marrow of both young and adult rabbit appeared as fast increase of enhancement and gradual washout pattern.The contrast materials in the tissue persisted in high concentration.The dynamic characteristics of the bone cortex were in accordance with the histologic findings.Conclusion：3D UTE pulse sequence can be used in the dynamic enhanced MRI of the tissues containing majority of short T2 components.