Hnatiuk Brad, Emery Derek J, Wilman Alan H
Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada.
J Magn Reson Imaging. 2008 Jan;27(1):71-7. doi: 10.1002/jmri.21225.
To determine whether three-dimensional (3D) contrast-enhanced MR angiography (CE-MRA) of carotid artery disease may be more effective when performed at double or triple the spatial resolution of the present common clinical standard at 1.5T.
A total of 110 consecutive patients with suspected carotid artery disease were imaged with elliptical centric 3D CE-MRA. The total acquisition time was increased from the standard clinical protocol of 21 seconds up to 60 seconds in 10-second steps, with corresponding voxel volume reductions from 0.95 mm(3) down to 0.35 mm(3). Quantitative and blinded qualitative measurements were then performed to determine the preferred imaging time.
In patients with significant stenosis, the 40-second acquisition with 0.53-mm(3) voxels produced significantly sharper images of the carotid bifurcation than the 21-second standard using 0.95-mm(3) voxels, but did not have a significant effect in patients without disease.
In patients with carotid artery stenosis, decreasing the voxel volume to 0.5 mm(3) by increasing the scan time from 21 to 40 seconds resulted in sharper depiction of the carotid stenosis. Further decreases in voxel volume, by extending the acquisition time further, did not improve the vessel depiction due to both signal-to-noise ratio (SNR) and sharpness losses.
确定在1.5T场强下，以当前常用临床标准空间分辨率的两倍或三倍进行颈动脉疾病的三维（3D）对比增强磁共振血管造影（CE-MRA）是否更有效。
连续110例疑似颈动脉疾病患者接受椭圆中心3D CE-MRA成像。总采集时间从标准临床方案的21秒以10秒为步长增加至60秒，相应的体素体积从0.95立方毫米减小至0.35立方毫米。然后进行定量和盲法定性测量以确定最佳成像时间。
在有明显狭窄的患者中，与使用0.95立方毫米体素的21秒标准采集相比，使用0.53立方毫米体素的40秒采集能产生明显更清晰的颈动脉分叉图像，但对无疾病的患者没有显著影响。
在颈动脉狭窄患者中，将扫描时间从21秒增加至40秒，使体素体积减小至0.5立方毫米，能更清晰地显示颈动脉狭窄。由于信噪比（SNR）和清晰度损失，进一步延长采集时间进一步减小体素体积并不能改善血管显示。
