MR DIGITAL SUBTRACTION ANGIOGRAPHY OF LOWER EXTREMITY

本研究的主要目的是开发和评价对比增强磁共振数字减影血管造影术（MRDSA），用于下肢动脉疾病的快速、无创和准确成像。 准确和无创的MRDSA将是一个具有成本效益的替代评估外周血管疾病。具体目标是：1）开发集成的3D和2D MRDSA技术，2）开发用于成像外周动脉病变频谱的策略，3）评估MRDSA在外周血管疾病患者中的临床可行性。MRDSA的3D和2D采集对于周围血管疾病的成像都具有优势和局限性。 我们计划克服它们的局限性并将它们的优点联合收割机结合起来。将开发交错螺旋3D技术，以优化信噪比、空间分辨率和扫描时间。将使用哈达玛编码、多重投影、超高平面内分辨率、磁化准备和数字滤波对2D序列进行细化。 3D和2D脉冲将被集成到一个序列中，以提供快速高分辨率动脉成像，而不会造成静脉污染。病理生理学决定了造影剂团的循环和治疗的成像需求。 因此，MRDSA的数据采集将根据病理生理条件进行调整。将通过定时扫描估计患者的疾病模式。将确定团注追踪MRDSA技术和相应的造影剂注射速率，以获得最佳SNR和空间分辨率以及最小静脉污染。 将开发由多站团注追踪采集和单个站高分辨率采集组成的综合成像策略，用于对广泛的外周血管疾病进行成像。将通过对一组周围血管疾病患者的MRDSA与X线血管造影进行比较，评价其临床可行性。 本研究的成功开展将使MRDSA成为一种准确、经济、无创的临床评估外周血管疾病的工具。

The broad objective of this research is to develop and evaluate contrast enhanced magnetic resonance digital subtraction angiography (MRDSA) for rapid, noninvasive and accurate imaging of arterial diseases in the lower extremity. Accurate and non-invasive MRDSA would be a cost-effective alternative for evaluating peripheral vascular disease. The specific aims are 1) develop integrated 3D and 2D MRDSA techniques, 2) develop strategies for imaging the spectrum of peripheral arterial pathology, 3) evaluate the clinical feasibility of MRDSA in patients with peripheral vascular disease. Both 3D and 2D acquisitions of MRDSA have advantages and limitations for imaging peripheral vascular disease. We plan to overcome their limitations and combine their advantages. Interleaved spiral 3D techniques will be developed to optimize signal-to-noise ratio (SNR), spatial resolution and scan time. 2D sequences will be refined with hadamard encoding, multiple projections, ultra high in-plane resolution, magnetization preparation, and digital filtering. Both 3D and 2D pulses will be integrated into one sequence to provide fast high-resolution arterial imaging without venous contamination. Pathophysiology determines the circulation of the contrast bolus and the imaging needs for therapy. Accordingly, data acquisition of MRDSA will be tailored to pathophysiologic conditions. Patients' disease patterns will be estimated with a timing scan. A bolus chase MRDSA technique and corresponding contrast injection rate will be identified for optimal SNR and spatial resolution and minimal venous contamination. A comprehensive imaging strategy consisting of multi-station bolus chase acquisition and individual station high-resolution acquisition will be developed for imaging a wide range of peripheral vascular disease. The clinical feasibility of MRDSA will be evaluated by comparing it with x-ray angiography in a group of patients with peripheral vascular disease. Successful development of this research will establish MRDSA as an accurate, economic and non-invasive clinical tool for assessing peripheral vascular diseases.