Department of Radiology, University Hospitals, Case Center for Imaging Research, Cleveland, Ohio, USA.
AJNR Am J Neuroradiol. 2012 Jan;33(1):77-82. doi: 10.3174/ajnr.A2737. Epub 2011 Nov 17.
MR imaging of moving patients can be challenging and motion correction techniques have been proposed though some have associated new artifacts. The objective of this study was to semiquantitatively compare brain MR images of moving patients obtained at 1.5T by using partially radial and rectilinear acquisition techniques.
FLAIR, T2-, T1-, and contrast-enhanced T1-weighted image sets of 25 patients (14-94 years) obtained by using BLADE (like PROPELLER, a partially radial acquisition) and rectilinear techniques in the same imaging session were compared by 2 neuroradiologists in terms of extent of the motion artifact, image quality, and lesion visibility. ICC between opinions of the evaluators was calculated.
Of the total of 70 image sets, the motion artifact was small in the partially radial images in 43 and in the rectilinear images in 13, and the opinions of the evaluators were discordant in the remaining 14 sets (ICC = 0.63, P < .05). The quality of partially radial images was higher for 36 sets versus 9 rectilinear sets, with disagreement between the 2 evaluators in the remaining 25 (ICC = 0.15, P < .05). Pathologic lesions were better characterized on 37 sets of partially radial images versus 13 sets of rectilinear images, and opinions of the evaluators differed in 20 sets (ICC = 0.90, P < .05). The neuroradiologists deemed 4 sets of rectilinear images nondiagnostic compared with only 1 set of radial images.
The data demonstrate that our application of BLADE sequences reduces the extent of motion artifacts in brain images of moving patients, improving image quality and lesion characterization.
对移动患者进行磁共振成像可能具有挑战性,已经提出了运动校正技术,但其中一些技术会产生新的伪影。本研究的目的是通过使用部分径向和直线采集技术,对 1.5T 上移动患者的脑磁共振图像进行半定量比较。
在同一次成像过程中,使用 BLADE(类似于 PROPELLER,一种部分径向采集)和直线技术对 25 例患者(年龄 14-94 岁)的 FLAIR、T2、T1 和增强 T1 加权图像进行采集,由 2 位神经放射科医师在运动伪影程度、图像质量和病变可见性方面进行比较。计算评估者意见的 ICC。
在总共 70 个图像集中,43 个部分径向图像的运动伪影较小,13 个直线图像的运动伪影较小,14 个图像集的评估者意见不一致(ICC=0.63,P<0.05)。36 个部分径向图像的质量较高,9 个直线图像的质量较高,其余 25 个图像集的评估者意见不一致(ICC=0.15,P<0.05)。37 个部分径向图像上的病理性病变特征更好,13 个直线图像上的病变特征较差,评估者的意见在 20 个图像集上存在差异(ICC=0.90,P<0.05)。神经放射科医师认为 4 个直线图像不可诊断,而只有 1 个部分径向图像不可诊断。
数据表明,我们对 BLADE 序列的应用减少了移动患者脑图像中的运动伪影程度,提高了图像质量和病变特征。