Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
J Magn Reson Imaging. 2012 May;35(5):1187-95. doi: 10.1002/jmri.23518. Epub 2011 Nov 29.
To describe in-phase (IP)/out-of-phase (OP) imaging with single shot magnetization-prepared gradient-recalled-echo (MP-GRE) and to compare intra-individually IP/OP MP-GRE with IP/OP three-dimensional gradient-recalled-echo (3D-GRE) at 3.0 Tesla (T).
Thirty-six subjects (15 males, 21 females; mean age 46.97 ± 14.97) who had abdominal MRI examinations including precontrast T1-weighted IP/OP MP-GRE, IP/OP 3D-GRE were included in the study. Two radiologists independently evaluated the sequences qualitatively for extent of artifacts, lesion detectability, and conspicuity and subjective grading of liver steatosis. Quantitative evaluation was performed by one radiologist and included liver fat index, liver and spleen SNR, and liver-lesion and liver-spleen CNR.
Respiratory ghosting was more pronounced on 3D-GRE (P < 0.0008). The degrees of parallel imaging residual artifacts, shading and blurring were significantly higher on the 3D-GRE sequences (P < 0.0008). Spatial misregistration and bounce point artifacts were only observed with MP-GRE images. Pixel graininess was more apparent on MP-GRE (P < 0.0008). Lesion detectability, confidence, and conspicuity were considerably higher on MP-GRE. Visual appreciation of steatosis was superior on 3D-GRE. Overall image quality was superior on MP-GRE (P < 0.0008).
Higher image quality and improved lesion detectability were present with IP/OP MP-GRE technique. Inversion-recovery prepared techniques may represent an important evolution for precontrast T1-weighted image at 3.0T. The good image quality of MP-GRE sequences acquired in a free breathing manner should recommend its use in patients unable to suspend breathing.
描述单次激发磁化准备梯度回波(MP-GRE)的同相位(IP)/反相位(OP)成像,并比较 3.0T 时个体内 IP/OP MP-GRE 与 IP/OP 三维梯度回波(3D-GRE)的成像。
本研究纳入了 36 例接受腹部 MRI 检查的患者(15 名男性,21 名女性;平均年龄 46.97±14.97 岁),包括对比前 T1 加权 IP/OP MP-GRE、IP/OP 3D-GRE。两位放射科医生独立对序列的伪影程度、病变检出率、肝脏脂肪变性的显影程度和主观分级进行定性评估。一位放射科医生进行了定量评估,包括肝脏脂肪指数、肝脾 SNR 以及肝病变与肝脾的 CNR。
呼吸鬼影在 3D-GRE 上更为明显(P<0.0008)。并行成像残留伪影、阴影和模糊程度在 3D-GRE 序列上显著更高(P<0.0008)。仅在 MP-GRE 图像上观察到空间配准错误和反弹点伪影。MP-GRE 上的像素颗粒感更明显(P<0.0008)。MP-GRE 上病变的检出率、信心和显影程度都明显更高。3D-GRE 上对脂肪变性的视觉评估更好。MP-GRE 的整体图像质量更高(P<0.0008)。
IP/OP MP-GRE 技术具有更高的图像质量和改善的病变检出率。反转恢复准备技术可能是 3.0T 时对比前 T1 加权图像的重要发展。MP-GRE 序列在自由呼吸状态下获得的良好图像质量应推荐其用于无法暂停呼吸的患者。