下肢CTA技术在糖尿病患者检查中的应用进展

Application progress of lower extremity CTA technology in the examination of patients with diabetes mellitus

目前下肢血管疾病的检查方法有踝肱指数、超声、磁共振成像(MRI)、CT血管造影(CTA)、数字减影血管造影(DSA)等技术。DSA一直被公认为是下肢血管疾病诊断的金标准,CTA与DSA相比较,其诊断的准确性和特异性最相似,而被广泛应用于外周血管疾病诊断,尤其是糖尿病患者。但糖尿病患者普遍肾功能不好,容易发生对比剂肾病,更多的对比剂用量加大了糖尿病患者发生对比剂肾病的风险。随着人们对CT辐射危害越来越重视,下肢CTA扫描范围长必然会增加辐射剂量。如何才能既减少对比剂用量又减少辐射剂量,真正实现“双低”CT血管成像,才是该技术能否被广泛应用于糖尿病患者的前提。能谱CT的单能量技术,可以保证影像质量满足诊断的前提下,降低下肢CTA检查时患者的对比剂用量,保护糖尿病患者的肾脏。合理地优化能谱CTA的扫描条件,尽可能减少扫描的辐射剂量,满足合理最低剂量原则。本文对能谱“双低”CTA技术及其临床应用进展进行综述,以期为糖尿病患者的检查提供参考。

At present,the examination methods of lower extremity vascular diseases include ankle brachial index,B-ultrasound,magentic resonance imaging(MRI),CT angiography(CTA),digital subtraction angiography(DSA)and so on. DSA has been recognized as the gold standard for the diagnosis of lower limb vascular diseases. Compared with DSA,CTA has the most similar accuracy and specificity in diagnosis,and is widely used in the diagnosis of peripheral vascular diseases,especially in diabetic patients.However, diabetic patients generally have poor renal function and are prone to contrast induced nephropathy. More contrast agents increase the risk of contrast induced nephropathy in diabetic patients.With people pay more and more attention to the harm of CT radiation,the long CTA scanning range of lower limbs will inevitably increase the radiation dose. How to reduce the dosage of contrast agent and the dose of radiation,achieving the "double low" CT angiography,is the premise of whether the technology can be widely applied to diabetic patients. The energy spectrum CT single energy technology can ensure the image quality to meet the premise of diagnosis,reduce the dosage of contrast agent in the lower extremity CTA examination,and protect the kidneys of diabetic patients. The scanning conditions of energy spectrum CTA should be reasonably optimized to reduce the scanning radiation dose as much as possible and meet the principle of reasonable minimum dose. In this paper,we review the technology of energy spectrum "double low" CTA and its clinical application,in order to provide a reference for the examination of diabetic patients.