实时透视触发三维动态增强磁共振血管成像技术及其在颈部动脉的应用

Three-dimensional dynamic contrast-enhanced MR angiography with real-time fluoroscopic triggering: techniques and clinical applications in carotid arteries

目的：探讨磁共振实时透视触发三维增强磁共振血管成像技术（3DDCEMRA）在颈部动脉临床应用的可行性。方法：颈部动脉疾病患者和颈部动脉正常者各30例，均行三维快速时间飞跃磁共振血管成像（3DTOFMRA）和3DDCEMRA。3DTOFMRA采用三维快速时间飞跃梯度回波（3DFGRE）序列，薄层、多层块轴位扫描；3DDCEMRA应用三维快速时间飞跃干扰梯度回波（3DFSPGR）序列，快速注射（注射速度2．0-3．0ml／s）对比剂钆一喷替酸葡甲胺（Gd．DTPA）20～25ml（0．15～0．2mmol／kg），磁共振实时透视触发即时扫描。两种方法所得全部原始图像在后处理工作站进行MIP重建，按解剖及影像诊断要求对颈部动脉的显示效果、颈部正常动脉连续性及边缘锐利度等进行比较评价。结果：60例颈部3DDCEMRA图像中，57例颈部动脉显示较佳，占95％；显示不佳3例，占5％；其中疾患组诊断为动脉硬化斑块3例、血管狭窄15例、血管闭塞6例、血管畸形4例、细小动脉瘤2例。3DDCEMRA对颈部动脉的显示效果、颈部正常动脉连续性及边缘锐利度等均优于3DTOFMRA（p〈0．001）。结论：3DDCEMRA对颈部动脉的硬化斑块、狭窄、闭塞、畸形、细小动脉瘤等病变的诊断均优于传统3DTOFMRA，具有较高的临床应用价值。

Objective： To investigate the feasibility of three-dimensional dynamic contrast-enhanced MR angiography （3DDCEMRA） with real-time fluoroscopic triggering in carotid arteries. Methods： Three-dimensional time of flight MR angiography （3DTOFMRA） and 3DDCEMRA were performed in 60 cases. 3DTOFMRA imaging sequence was three-dimensional fast gradient echo with thin slice and multi-slab, and 3DDCEMRA imaging sequence was three-dimensional time of flight spoiled gradient echo. The 20-25 ml Gd-DTPA was injected with the rate of 2.0-3.0 ml/sec and the dose 0.15-0.2 ml/kg. With the MR fluoroscopic triggering technique, all the primary graphs were analyzed by maximum intensity projection reconstruction in the pest processing station. The image qualities, included sensitivity, continuity and sharp-edged degree of these two different techniques were evaluated according to the diagnosed demand and dissecting. Results： Major branch was displayed in 57 cases, which presented 95% of total of cases classified as good image quality. 3DDCEMRA had significantly higher sensitivity, continuity, and sharp-edged degree than 3DTOFMRA in evaluation of carotid arteries. Conclusion： 3DDCEMRA is an effectively and minimally invasive method for evaluating lesions in carotid arteries.