Quantitative analysis of ECG-gated high-resolution contrast-enhanced MR angiography of the thoracic aorta
Quantitative analysis of ECG-gated high-resolution contrast-enhanced MR angiography of the thoracic aorta
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DOI：
10.2214/ajr.05.1467
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发表时间：
2007-02-01
影响因子：
5
通讯作者：
Carr, James C.
中科院分区：
文献类型：
--
作者：
Groves, Elliott M.;Bireley, William;Carr, James C.
OBJECTIVE.本研究的目的是评价对比增强MR血管造影与无心脏门控的MR血管造影相比，心脏门控对不同水平胸主动脉图像质量的影响。50例患者在1.5 T全身系统上进行了高分辨率对比增强MR血管造影。50例患者分为两组，每组25例连续患者;一组接受ECG门控MR血管造影，另一组接受无ECG门控MR血管造影。采用矢状（3D）梯度回波快速低角度激发（FLASH）序列（TR/TE，2.8/1.4;翻转角，25度;读数，512;体素大小，1.4 x 0.8 x 1.3 mm），所有三个梯度轴均采用非对称k空间扫描方案，以2 mL/s的速度注射0.2 mmol/kg钆喷酸葡胺。通过生成跨越主动脉血管壁的信号强度曲线并计算沿代表信号强度曲线斜率的线沿着两点之间的距离，在三个水平上评价胸主动脉的Sharpness。对强度分布的两侧进行分析和平均，然后用于计算锐度。另一组6例患者接受了门控和非门控序列;对该组的结果进行独立分析。对升胸主动脉锐度的定量分析显示，在50例患者组和6例患者组中，增加心脏门控后，升胸主动脉锐度显著增加（p < 0.005）。心脏门控显著提高了升主动脉的清晰度，升主动脉是心脏运动引起的大量模糊的一部分。高分辨率对比增强磁共振血管造影与心脏门控可以产生高质量的图像胸部血管，从而使血管疾病的准确诊断。
OBJECTIVE. The purpose of this study was to evaluate the effect of cardiac gating on the quality of images of the thoracic aorta at various levels during contrast-enhanced MR angiography compared with MR angiography without cardiac gating.MATERIALS AND METHODS. Fifty patients underwent high-resolution contrast-enhanced MR angiography on a 1.5-T whole-body system. The 50 patients were composed of two groups of 25 consecutive patients; one group underwent MR angiography with ECG gating and the other group underwent MR angiography without ECG gating. A sagittal (3D) gradient-echo fast low-angle shot ( FLASH) sequence (TR/TE, 2.8/1.4; flip angle, 25 degrees; readout, 512; voxel size, 1.4 x 0.8 x 1.3 mm) with an asymmetric k-space scanning scheme in all three gradient axes was used, and 0.2 mmol/kg of gadopentetate dimeglumine was injected at 2 mL/s. Sharpness of the thoracic aorta was evaluated at three levels by generating a signal intensity profile across the aortic vessel wall and calculating the distance between two points along a line representing the slope of the signal intensity profile. Both sides of the intensity profile were analyzed and averaged and then used to calculate sharpness. An additional group of six patients was included who had undergone both a gated and an ungated sequence; results of this group were analyzed independently.RESULTS. Quantitative analysis of the sharpness of the ascending thoracic aorta showed a significant increase in sharpness in both the 50-patient and six-patient groups (p < 0.005) with the addition of cardiac gating.CONCLUSION. Cardiac gating significantly improves the sharpness of the ascending aorta, a portion of the aorta that is subject to a great deal of blurring caused by cardiac motion. High-resolution contrast-enhanced MR angiography with cardiac gating can produce high-quality images of the thoracic vasculature, thus enabling accurate diagnosis of vessel disease.