低剂量增强高场MR下肢动脉造影的初步模型实验及临床应用  

An in vitro experimental study and clinical applications of MR angiography with low-dose contrast agent of lower limb arteries at 3.0 T

作　　者：张磊 畅坚 师东春 顾洪斌 李科 朱磊 胡自建 金真 许樟荣 

机构地区：[1]解放军第三○六医院医学影像科,北京100101 [2]解放军第三○六医院心胸外科,北京100101 [3]解放军第三○六医院糖尿病中心,北京100101

出　　处：《中华放射学杂志》2010年第10期1078-1083,共6页Chinese Journal of Radiology

摘　　要：目的 探讨高场MR下肢动脉增强造影（contrast-enhanced MRA,CE-MRA）使用较低剂量对比剂的可行性及临床应用价值.方法 应用3 T MR仪,测定对比剂Gd-DTPA浓度（0.5～6.0 mmol/L）与CE-MRA信号强度的关系.选定临床可能应用的浓度值（0.5、1.5、2.5、4.0 mmol/L）,对人造血管狭窄模型进行CE-MRA扫描并与DSA相对比,依据管腔表现能力初步确定适合于临床应用的对比剂低剂量范围.之后选用较低剂量13 ml Gd-DTPA（相当于1.1～1.3 mmol/L血液浓度）对78例糖尿病患者下肢动脉进行了三段法CE-MRA扫描,对图像质量进行评价,并对小腿动脉狭窄诊断率及其静脉污染影响程度进行了Fisher＇s确切检验.将其中有DSA检查的22例按照不同动脉节段（共220节段）及狭窄程度（划分为4级）与DSA结果进行了Kappa一致性检验.结果 Gd-DTPA在0.5～6.0 mmol/L范围内,浓度与信号强度呈线性正相关,应用较低浓度（1.5 mmol/L）Gd-DTPA进行CE-MRA可获得血管模型狭窄信息.临床数据分析表明低剂量对比剂对于膝以上动脉成像可诊断率达97.4%（76/78）,膝以下动脉造影质量受静脉污染显著影响,污染存在与否其诊断率分别为20.0%（31/155）及43.2%（67/155）（P＜0.01）.22例患者以DSA为标准,CE-MRA诊断狭窄的敏感度及特异度分别为96.0%（168/175）及73.3%（33/45）（K=0.72,P＜0.01）;但膝以下动脉诊断符合率（K值0.43～0.63）低于膝以上动脉（K值0.75～0.82）.结论 低剂量13mlGd-DTPA可以应用于临床下肢动脉狭窄性病变的CE-MRA检查,并且与DSA相比具有较高的诊断敏感度及特异度,但小腿静脉污染是CE-MRA检查中需要克服的缺陷.Objective To evaluate the feasibility and diagnostic accuracy of CE-MRA with low dose contrast agent by comparison with DSA in diabetic patients with peripheral arterial diseases. Methods （ 1 ）Study in vitro： test tubes containing Gd-DTPA of different concentrations were scanned, and the relationship between signal intensities and concentrations of GD-DTPA was analyzed. DSA and CE-MRA with selected concentrations of Gd-DTPA were performed on stenotic vascular models to estimate the proper low dose of GD-DTPA for clinical applications. （2） Clinical applications： 78 diabetic patients with peripheral arterial diseases were scanned from the abdomen and pelvis station to the calf-foot station in a 3 T MR system with standard bolus chase 3D CE-MRA sequence after injection of 13 ml GD-DTPA . The image quality,diagnostic rate of stenosis of arteries in calf and degree of venous contamination were evaluated with Fisher＇s exact test. DSA images of 220 vascular segments in 22 patients （ 10 segments per patient） were acquired as the gold standard and compared with CE-MRA by using Kappa test. Results The MR signal intensities were proportional to the concentrations of contrast agent in present study, and all stenotic segments of vascular model were displayed by CE-MRA with GD-DTPA at lower concentration of 1.5 mmol/L. As for MRA images of 78 diabetic patients with low dose Gd-DTPA, about 97.4% （76/78） showed diagnostic image quality for pelvic and thigh stations. But the MRA images of lower extremities were interfered by the venous contamination significantly （P ＜ 0.01 ）. Compared with DSA for 22 patients, the diagnostic sensitivity, specificity and agreement coefficient （Kappa value） of MRA were 96. 0% （ 168/175）, 73.3%（33/45）, and 0.72 （P＜0.01）, respectively. Conclusion Using 3.0 T MR scanner, high quality CE-MRA of lower limb arteries can be obtained for clinical applications with contrast agent dose as low as 13 ml,which has comparable diagnostic sensitivity and specificity wi

关 键 词：磁共振血管造影术 造影剂 小动脉 下肢 糖尿病血管病变 

分 类 号：R686[医药卫生—骨科学]