透视触发并行采集高分辨率三维增强颈动脉磁共振血管成像术

目的评估透视触发和并行采集技术用于高分辨率三维增强颈动脉磁共振血管成像术(3DCEMRA)的可行性。方法80个临床诊断或怀疑颈动脉狭窄的病人接受3DCEMRA检查。使用透视触发软件触发启动颈动脉3DCEMRA扫描,同时采用K空间椭圆形中心填充法和加速因子为2的并行采集技术。对显示的各段动脉和有无静脉早期显影做分析。动脉狭窄分成动脉管壁不规则、轻度狭窄、严重狭窄和闭塞。颈动脉3DCEMRA的显示结果与其他检查结果做了对照。结果所有病例均顺利触发和完成颈动脉3DCEMRA检查。3DCEMRA显示了80例病人总共800支动脉段(100%显示率),所有病例在动脉显示区域内静脉均未显影或显影很淡,对诊断不构成影响。结果显示有680段动脉正常、41段动脉管壁不规则、24段动脉轻度狭窄、51段严重狭窄和4段闭塞。另外10段颈动脉狭窄处溃疡形成,12例患者除见颈动脉狭窄以外,还发现合并椎动脉和/或锁骨下动脉狭窄。36例病例,与其他血管成像技术作了比较,3DCEMRA的检查结果与之完全符合,未出现高估或低估血管狭窄程度。结论透视触发并行采集高分辨率3DCEMRA简单可行,成像时间短,空间分辨率高,能清楚显示颈动脉,它将在颈动脉狭窄的诊断中起重要作用。

High-resolution 3D Contrast-Enhanced MR Angiography of the Carotid Arteries with Fluoroscopic Triggering and Parallel Acquisition Techniques

Objective To evaluate the feasibility and diagnostic performance of high-resolution 3D contrast-enhanced MR angiography (3D CE MRA) of the carotid arteries with fluoroscopic triggering and parallel acquisition techniques.Methods 80 patients with clinically diagnosed or suspected carotid artery stenosis underwent high-resolution 3D CE MRA of the carotid arteries. A real-time sequence was used to fluoroscopically monitor the contrast arrival in the aortic arch and trigger the high-resolution 3D CE MRA of the carotid arteries. 3D CE MRA used elliptical centric view order to fill the K-space. Parallel acquisition technique with acceleration factor of 2 was also used. The overall image quality of each arterial segment was evaluated. Early venous contamination was scored. The presence of arterial stenosis was evaluated and classified into the following: vessel irregularity,mild stenosis, significant stenosis and occlusion. 3D CE MRA findings were also compared to other imaging modalities if available. Results 3D CE MRA of the carotid arteries was successfully triggered and performed in all patients. Our study identified all 800 arterial segments in all subjects (100%). Venous contamination was rated as none or minimal and never interfered with arterial diagnosis. The results showed 680 normal arterial segments and 120 arterial segments with pathology including 41 segments with irregularity,24 segments with mild stenosis,51 segments with significant stenosis and 4 segments with occlusion. 3D CE MRA found ulceration in 10 segments of carotid artery. In 12 patients with carotid artery stenosis, additional stenosis was foundin vertebral and/or subclavian arteries . In 36 cases with other imaging techniques available , the demonstration of vascular pathology allagreed by 3D CE MRA without over-or underestimation.Conclusion High-resolution 3D CE MRA of the carotid arteries withfluoroscopic triggering and parallel acquisition techniques is feasible and easy to perform. It can reduce imaging time and improve spatial resolution. It can depict the carotid arteries clearly and will play an important role in diagnosis of carotid arterial stenosis.