Stress-rest calf muscle perfusion: a functional diagnostic test for peripheral arterial disease (PAD)

在美国，外周动脉疾病(PAD)每年影响近800万人，造成210亿美元的损失。使用 由于腿部血液供应减少，一些患者在行走时会感到小腿疼痛或疲劳。虽然垫 可以可靠地检测到脚踝低血压，以及解剖成像(MRI或CT)的狭窄 为了选择最佳的治疗方法，我们需要一种无创性的测试来评估小腿肌肉功能。 在这个项目中，我们建议使用高分辨率磁共振成像(Mri)来测量血液 在不同组的小腿肌肉中灌流，并在低负荷和高负荷后重复测量 锻炼小腿肌肉。这种负荷-静息成像方法是评估冠状动脉的标准方法。 疾病(CAD)，从来没有成功地应用于PAD。我们的初步结果显示出不同的模式 在健康患者和PAD患者之间的肌肉灌注率，因此这项技术前景广阔。在这4年中 项目中，我们将首先改进灌注成像方法，验证其重复性，然后与小牛进行比较 PAD患者与年龄匹配的健康对照的肌肉灌注测量。这一比较 将检验检测PAD患者功能异常的可行性。基线扫描后，PAD 患者将接受为期12周的监督运动疗法，然后在治疗后进行核磁共振扫描。比较 治疗前和治疗后的测量结果将表明治疗如何改善小腿肌肉的血流灌注， 以及这种血流变化如何与患者行走能力的增加相关。 该项目的长期目标是为PAD患者开发一种改进的诊断测试 预测谁将从治疗干预中受益。小腿肌肉的应激-静息灌流研究可以 结合常规外周MRA检查，评估血管狭窄的功能意义。 与常规的心脏负荷成像方法一样，小牛的功能测量得到了改进 在测试和开发改进的治疗方法时，灌流也应该被证明是有用的。

Peripheral arterial disease (PAD) affects nearly 8 million people and costs >$21B in the U.S. per year. With reduced blood supply to their legs, some patients experience calf pain or fatigue with walking. Although PAD can be reliably detected by a low ankle blood pressure, and anatomic imaging (MRI or CT) of the narrowing arteries, to select the best treatment approach, we need a non-invasive test to assess calf-muscle function. In this project, we propose to use high-resolution magnetic resonance imaging (MRI) to measure blood perfusion in different groups of calf muscle, and repeat the measurement after a low-load and a high-load exercise of calf muscle. This stress-rest imaging approach is standard of care for evaluation of coronary artery disease (CAD), and has never been successfully applied to PAD. Our preliminary results show distinct patterns of muscle perfusion between healthy and PAD patients, and thus great promise of the technique. In this 4-year project, we will first refine the perfusion imaging method, verify its reproducibility, and then compare the calf muscle perfusion measures in PAD patients against healthy age-matched healthy controls. This comparison will test the feasibility of detecting functional abnormality in PAD patients. After the baseline scans, the PAD patients will undergo a 12-week supervised exercise therapy, and then a post-therapy MRI scan. Comparison of the pre- and post-therapy measurement will indicate how the therapy improves the calf-muscle perfusion, and how this perfusion change correlates with increase in patient’s walking ability. The long term goals of this project are to develop an improved diagnostic test for patients with PAD to predict who will benefit from therapeutic intervention. The stress-rest perfusion studies of calf muscle can be performed in conjunction with routine peripheral MRA to assess the functional significance of vascular stenosis. As with the routinely performed cardiac stress imaging methods, improved functional measures of calf perfusion should also prove useful in the testing and development of improved therapeutic approaches.