Optimization of contrast-enhanced MR angiography : basic and clinical investigations

为了优化MR血管成像，我们采用1.5 t临床MR系统和4.7 t实验MR系统进行了以下成像实验：(1)设计并制作了具有稳定、脉动和湍流的血管模型；(2)利用飞行时间、相位对比和增强磁共振血管成像技术对血管模型进行成像，研究最佳脉冲序列（包括重复时间、回波时间、翻转角度和流动灵敏度）和造影剂注射方法；(3)采用飞行时间、相位对比和增强磁共振血管成像技术对动物血管进行成像，并探讨了最佳脉冲序列和注射造影剂的方法；(4)在血管模型和动物血管上制造人工血管狭窄，研究MR血管造影评价血管狭窄的最佳脉冲序列和造影剂注射方法。我们对怀疑患有血管疾病的患者进行了优化的MR血管造影，并将其与常规血管造影结果进行了比较，并评估了MR血管造影的诊断准确性。优化的MR血管造影和增强的MR血管造影能清晰地显示脑血管病变（烟雾病）和主动脉病变（高松动脉炎），对脑血管和主动脉疾病的诊断具有较高的准确性。优化后的磁共振增强血管造影清晰地描绘了头颈部血管瘤，并能显示血管瘤的诊断和亚型。我们正在进行针对各种血管疾病进行优化的MR血管造影。此外，我们正计划优化全身各个部位的动脉和静脉的MR血管造影。

In an attempt to optimize MR angiography, we performed the following imaging experiments using 1.5-T clinical MR system and 4.7-T experimental MR system : (1) we designed and made vascular models which have steady, pulsatile, and turbulent flows ; (2) we imaged the vascular models using time-of-flight, phase contrast, and contrast-enhanced MR angiography, and investigated the optimal pulse sequences (including repetition time, echo time, flip angle, and flow sensitivity) and injection methods of contrast medium ; (3) we imaged various vessels of animals using time-of-flight, phase contrast, and contrast-enhanced MR angiography, and investigated the optimal pulse sequences and injection methods of contrast medium ; and, (4) we made artificial stenoses in the vascular models and animal vessels, and investigated the optimal pulse sequence and injection methods of contrast medium to evaluate the stenoses with MR angiography.We performed the optimized MR angiography for patients suspected of having vasculardiseases, compared the findings with conventional angiographic findings, and evaluated the diagnostic accuracy of MR angiography. Optimized MR angiography and contrast-enhanced MR angiography clearly depicted the cerebrovascular lesions (moyamoya disease) and aortic lesions (Takayasu arteritis), and showed a high accuracy for the diagnosis of cerebrovascular and aortic diseases. Optimized contrast-enhanced MR angiography clearly depicted head and neck hemangiomas, and it was able to show the diagnosis and subtype of hemangiomas.We are performing MR angiography that was optimized for various vascular diseases.Furthermore, we are planning to optimize MR angiography for arteries and veins in each site of the whole body.