Contrast Free MRI for Imaging Vascular Calcification in Diabetic Lower Extremity

糖尿病是外周动脉疾病(PAD)和 同时患有PAD和糖尿病的患者更有可能出现伤口形成、感染和 肢体丧失的风险更高。在糖尿病的背景下，PAD的一个特征是浓集的 胫骨动脉和足底动脉钙化、顽固性闭塞症。然而，很难做到 无创性评估胫骨和足底流出动脉的通畅性 糖尿病患者肢体多节段、弥漫性、钙化斑块。在……里面 此外，目前临床诊断工具中使用的造影剂，如数字减影 血管造影术(DSA)、计算机断层血管造影术(CTA)或增强对比 磁共振血管造影术是有肾脏疾病的糖尿病患者的禁忌 不够用。 无对比磁共振血管成像(CF-MRA)成为一种有利的检查方法 这些患者的影像检查方法。目前的CF-MRA技术显示出良好的敏感性 和特异性检测下肢动脉狭窄，但依赖于 心电图仪(ECG)触发。糖尿病患者的异常心电信号 更有可能超重和/或肥胖导致不理想的或无用的血管造影结果。 更重要的是，目前的CF-MRA技术没有可靠的方法来评估 动脉壁钙化。本研究的目的是开发和验证一种新的CF-MRA 技术，不使用任何心电信号，以评估动脉狭窄和钙化。 将解决两个具体目标。在特定目标1中，一种新的CF-MRA技术 开发动脉流出道血管狭窄和钙化的定量测量方法 并在3D打印的钙化血管模型中进行了验证。在具体目标2中，敏感性和 血管钙化和狭窄检测的特异性将在较低的 应用新的CF-MRA技术对25例有症状的PAD和糖尿病患者的四肢进行检查， 分别与CTA和DSA进行比较。据推测，钙化的程度 而新的CF-MRA测量的狭窄程度将与实际情况强烈相关 模型中钙化和狭窄的大小(r&gt；0.9)。高灵敏度和高特异度(&gt；90%) 使用新的CF-MRA将实现对钙化和狭窄的检测。这个 这项研究的完成将为全面评估心脏血管系统奠定基础 PAD和糖尿病患者的下肢，这对有效的治疗计划是必不可少的 用于血运重建和肢体保肢。

Diabetes is an important independent risk factor for peripheral arterial disease (PAD) and patients with both PAD and diabetes are more likely to have wound formation, infection, and higher risk of limb loss. A hallmark of PAD in the setting of diabetes, is the accumulation of densely calcified, recalcitrant, occlusive disease of the tibial and pedal arteries. However, it is difficult to non-invasively assess patency of tibial and pedal outflow arteries accurately in the lower extremities of the patients with diabetes, due to multi-segment, diffuse, and calcified plaques. In addition, the contrast media used in current clinical diagnostic tools, such as digital subtraction angiography (DSA), computerized tomographic angiography (CTA), or contrast-enhanced magnetic resonance angiography, are contraindicated to patients with diabetes who have renal insufficiency. The contrast free magnetic resonance angiography (CF-MRA) becomes a favorable imaging method in these patients. Current CF-MRA techniques demonstrated good sensitivity and specificity for the detection of arterial stenosis in lower extremities, but relies on the electrocardiography (ECG) triggering. Irregular ECG signals in patients with diabetes who are more likely to be overweight and/or obese results in suboptimal or useless angiographic findings. More importantly, current CF-MRA techniques have no robust methods to assess the extent of arterial wall calcification. The objective of this study is to develop and validate a new CF-MRA technique, without using any ECG signal, to assess both arterial stenosis and calcification. Two specific aims will be addressed. In Specific Aim 1, a new CF-MRA technique for quantitative measurements of arterial outflow vessel stenosis and calcification will be developed and validated in a 3D printed calcified vascular phantom. In Specific Aim 2, sensitivity and specificity of vascular calcification and stenosis detection will be determined in the lower extremities of 25 patients with symptomatic PAD and diabetes using the new CF-MRA technique, in comparison with CTA and DSA, respectively. It is hypothesized that the extent of calcification and stenosis degree measured by the new CF-MRA will be strongly correlated with the actual size of calcification and stenosis in the phantom (r > 0.9). High sensitivity and specificity (> 90%) will be achieved for the detection of calcification and stenosis with the new CF-MRA. The completion of this study will build a foundation to comprehensively assess the vasculature in the lower extremities of patients with PAD and diabetes, which is essential to effective treatment plans for revascularization and limb salvage.