平衡稳态自由进动序列非增强MR血管成像在糖尿病患者足部动脉成像中的应用研究

目的 评价基于血流敏感散相为准备脉冲的平衡稳态自由进动序列非增强MR血管成像(FSD-bSSFP NC-MRA,简称FSD-bSSFP),在糖尿病周围血管病变患者足部动脉成像中的临床应用价值.方法 对43例有足部症状的糖尿病患者采用FSD-bSSFP序列和三维对比增强序列(CEMRA)进行足部动脉成像.然后由2名有经验的放射科医师共同对2种成像技术的足部动脉图像质量、静脉污染和足部动脉分支的显示情况进行评分.采用Wilcoxon秩和检验对FSD-bSSFP和CEMRA图像质量、静脉污染情况、足背动脉及分支显示情况进行统计学分析;对2组图像足背动脉的信号强度(SI)、信噪比(SNR)和对比噪声比(CNR)采用配对t检验进行比较.结果 FSD-bSSFP的图像质量评分为(2.7±1.1)分,CE-MRA为(2.6±0.8)分,两种扫描序列的图像质量差异无统计学意义(Z=0.134,P＞0.05).FSD-bSSFP对足背动脉分支显示情况良好,为(3.2±0.9)分,CE-MRA为(2.5±0.9)分,两者间差异有统计学意义(Z=5.246,P＜0.05).FSD-bSSFP静脉污染为(1.8±0.4)分,CE-MRA为(2.1±0.8)分,两者间差异有统计学意义(Z=2.541,P＜0.05).FSD-bSSFP图像的SNR为148.6±26.7,CNR为88.3±19.0.3D CE-MRA图像的SNR为148.5±45.6,CNR为121.0±41.0.两者间SNR差异无统计学意义(t=0.013,P＞0.01),CE-MRA CNR高于FSD-bSSFP,差异有统计学意义(t=5.113,P＜0.05).结论 FSD-bSSFP非增强MRA可获得较好的足部动脉图像,可显示足背动脉及三级分支,为肾功能不全或其他原因不能使用对比剂的患者提供一个安全有效的补充方法.

A study of arteries of foot by flow sensitive dephasing prepared balanced steady-state free precession MR angiography in diabetes

Objective To investigate balanced steady-state free precession with flow-sensitive dephasing magnetization preparation (FSD-bSSFP) in the assessment of arteries of foot in diabetic patients.Methods The lower-extremity peripheral arteries of 43 diabetic patients were evaluated by FSD-bSSFP no contrast MRA and contrast-enhanced MRA (CE-MRA)in. Two experienced observers assessed the image quality, degree of venous contaminated and visibility of pedal artery branches by FSD-bSSFP and CE-MRA respectively in consensus. The signal intensity( SI), signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the source images of both groups were measured and Wilcoxon and t tests were performed. Results The image score of FSD-bSSFP group was 2.7 ± 1.1 and CE-MRA was 2.6 ± 0.8, there was no statistical difference ( Z = 0. 134, P ＞ 0. 05 ). The image score of demonstration of the pedal artery branches and degree of venous contamination on FSD-bSSFP were 3.2 ± 0. 9 and 1.8 ± 0. 4 respectively which were superior to that of CE-MRA (2.5 ± 0.9 and 2.1 ± 0.8 respectively). Significant statistical difference existed between the two groups in demonstration of pedal artery branches ( Z = 5.246, P ＜ 0.05 ) and degree of venous contamination (Z =2.541 ,P ＜0.05). SNR of FSD-bSSFP was 148.6 ±26.7, CNR was 88.3 ± 19.0. SNR of CE-MRA was 148.5 ± 45.6, CNR was 121.0 ± 41.0. No statistical difference existed between SNR between two methods (t = 0.013, P ＞ 0.05 ). But CNR of CE-MRA was superior to that of FSD-bSSFP and significant statistical difference existed between these two methods ( t = 5.113, P ＜ 0.01 ). Conclusion FSD-bSSFP without contrast could be used in the evaluation of foot arteries in patients of renal dysfunction and diabetes.