双源CT“双低”成像在冠状动脉桥血管的初步研究

Preliminary study of“double low”Dual-source coronary CT angiography in coronary artery bypass grafts

目的评价双源CT"双低"成像在冠状动脉桥血管检查的可行性和有效性。方法连续入组38例冠状动脉搭桥术后患者。冠状动脉CT血管造影(CCTA)采用前瞻性心电触发序列扫描、低管电压结合迭代算法,采用等渗低浓度碘对比剂碘克沙醇(270mgI/ml)。其中20例患者进行了有创冠状动脉造影(CAG)检查。两位评价者评价桥血管的CTA图像质量和是否存在显著狭窄(≥50%)和闭塞,以CAG为参照标准,评价CCTA诊断桥血管显著狭窄和闭塞的敏感性、特异性、阳性预测值(PPV)和阴性预测值(NPV)。结果 38例患者共评价76支桥血管,按照分段,评价387段桥血管,可诊断的血管段达到99.5%(385/387)。20例造影患者中以CAG为参照标准,CCTA诊断桥血管显著狭窄的敏感性、特异性、PPV和NPV分别为100%(4/4)、97.6%(40/41)、80.0%(4/5)和100%(40/40)。CCTA准确诊断了9支闭塞的桥血管。结论双源CT"双低"扫描方案对于桥血管检查具有可行性,该扫描方案可以显著降低辐射剂量和对比剂的碘负荷而保证诊断所需图像质量。对桥血管显著狭窄和闭塞的诊断准确性较高。

Objective To evaluate the feasibility and effectiveness of “double low”coronary CT angiography （CCTA） in patients with coronary artery bypass grafts （CABG） .Methods A total of 38 consecutive patients underwent CABG follow up with CCTA were prospectively enrolled .Prospectively ,ECG‐triggered sequential imaging with low tube voltage and it‐erative reconstruction integrating with low concentration Iodixanol 270 （270 mgI/ml） were used in CCTA study .Of the enrolled patients ,20 cases also underwent invasive coronary angiography （CAG） .Subjective assessment of image quality and presence of significant stenosis （≥50% ） and occlusion of coronary grafts was performed .The sensitivity ,specificity , positive predictive value （PPV） ,and negative predictive value （NPV） were calculated using CAG as the reference stand‐ard .Results A total of 76 CABG vessels were analyzed .In total 387 segments of coronary grafts evaluated ,385（99 .5% ） segments were diagnostically evaluable .The sensitivity ,specificity ,PPV ,and NPV of CCTA for diagnosing the signifi‐cant stenosis of coronary grafts were 100% （4/4） ,97 .6% （40/41） ,80 .0% （4/5） ,and 100% （40/40） .Nine occluded coro‐nary grafts were accurately diagnosied with CCTA .Conclusion “Double low” CCTA is feasible in patients with CABG . This protocol can reduce the radiation dose and iodine load while maintaining diagnostic image quality and is accurate to di‐agnose significant stenosis and occlusion of CABG .