多时相ASL技术及非对比增强功能性MRA评估移植肾的灌注及血管功能的基础研究

肾移植术后早期发现并及时处理可能发生的各种肾血管并发症及肾实质损伤是提高手术成功率的关键，这需要建立在准确的诊断与评估基础之上。使用对比剂的CT或MRI技术可评估血管的形态学改变及肾灌注状况，是目前肾移植术后评估的主要方法。但对比剂的使用可能会导致对比剂肾病或肾源性系统性纤维化（NSF），故已有肾功能损害的患者需慎重使用对比剂。本项目在前期研究基础上，采用SLEEK序列结合4D-flow技术，探索一种无需对比剂获得高质量三维血管图像的同时获得流速、血管切应力等功能参数的新型磁共振功能性血管成像技术，为指导肾动脉狭窄介入治疗提供更可靠依据；同时，在现有单时相ASL的基础上开发多时相ASL技术，以更准确评估肾灌注状况，联合DWI实现更准确肾实质损伤的评估。这些技术可能获得较现有技术更好的评估效果，且无需对比剂，避免了对比剂肾病及NSF的发生，因此其临床实用性强，将产生良好的经济效益与社会效益。

The key to improve the success rate of kidney transplantation is that the potential post-operational renal vascular complications and renal parenchyma damages are early detected and timely treated, and the treatment strategy is largely depend on the accurate diagnosis and precise assessment. Presently, the angiography and perfusion imaging by CT or MRI using contrast agents are the main methods for assessing the abnormalities of vascular morphology and renal perfusion after renal transplantation. However the use of contrast agents may lead to contrast-induced nephropathy and gadolinium contrast agent may result in nephrogenic systemic fibrosis, which may hamper those methods to be performed on the patients with renal dysfunction. Developed from our previous researches on this respect, the project aimed to develop a new technique of magnetic resonance angiography without contrast agents by an integrated pulse sequence with SLEEK (spatial labeling with multiple inversion pulses) and 4D flow MRI technique. With this new technique, not only can the high-quality 3-Dimensional vascular images be obtained, but also the functional parameters such as the speed of blood flow, vascular shear stress are accurately measured, which may provide more reliable information for guiding the interventional management on renal artery stenosis. Meanwhile, in the project, multiple-phase arterial spin labeling (ASL) technique is developed from currently adopted single-phase ASL with an attempt to a better evaluation of renal perfusion, and diffusion-weighted imaging is combined with it to a more accurately evaluation of the parenchyma damages of transplanted kidney. Compared to the current methods, these new methods need no contrast agents which can thoroughly avoid the incidence of contrast induced nephropathy and nephrogenic systemic fibrosis, yet may have the better value in evaluating the post-operational renal vascular complications and renal parenchyma damages. Therefore, broad clinical use and good economic and social benefits are expected.