T1-Weighted Imaging of the Brain at 3 Tesla Using a 2-Dimensional Spoiled Gradient Echo Technique
T1-Weighted Imaging of the Brain at 3 Tesla Using a 2-Dimensional Spoiled Gradient Echo Technique
复制标题
使用二维破坏梯度回波技术在 3 特斯拉下对大脑进行 T1 加权成像
作者：
V. Runge;Mittun C. Patel;S. Baumann;Alexander B. Simonetta;J. Ponzo;W. Lesley;G. W. Calderwood;L. Naul
理由和目的：本研究的目的是评估二维破坏梯度回波 (GRE) 成像方法，使用非常短的同相 TE 在 3 T 下对大脑进行常规 T1 加权成像。材料和方法：对紧邻配备类似设备的 1.5 T 设备的 3 T 磁共振 (MR) 设备进行患者检查进行比较。在 1.5 T 与 3 T 下对对比前和对比后 T1 加权图像进行评估，并与 1.5 T 下使用的二维 (2-D) 自旋回波序列和 3 T 下使用的 2-D GRE 序列进行比较。所使用的 2 个 MR 系统来自同一供应商，使用类似的 8 通道线圈，并使用相同的梯度。 T1 加权 GRE 序列在 3 T 下使用，依靠短 TE (2.4 ms) 来限制与血流相关的伪影和磁敏度伪影。对两种场强下的 16 名不同矢状患者检查（总共 32 次）进行了感兴趣区域分析，并对 10 次不同的对比前和对比后轴向检查（总共 40 次）进行了类似的分析。四位盲法神经放射学家也评估了这些研究。结果：使用描绘尾状核的中线矢状切片（信噪比 [SNR] 163 ± 28 vs. 70 ± 7、3 T vs. 1.5 T）和放射冠（SNR 214 ± 35 vs. 82 ± 10），3 T 在 SNR 和对比度噪声比方面均明显优于 1.5 T (CNR) (51 ± 14 vs. 12 ± 5).在轴向成像中，尽管切片厚度（5至3毫米）和扫描时间（5至1分钟）减少，但与3和1.5 T相比，对比前或对比后的SNR和CNR没有显着差异。在盲法胶片审查中，在运动伪影（减少）、灰白质分化和整体图像质量方面，3 T在矢状扫描上的表现略好于1.5 T。在轴向扫描中，3 T 在所有 3 个类别中（无论是对比前还是对比后）均表现明显更好。就整体图像质量而言，首选 3 T，9:2 前对比度和 4:1 后对比度。结论：使用短 TE 2-D GRE 技术可以在 3 T 下轻松进行高质量薄切片 (3 毫米) T1 加权成像。与 1.5 T 成像相比，这种方法提供了卓越的 SNR 和 CNR，同时减少了运动伪影和扫描时间，并被提倡用于 3 T 的常规脑成像。它很强大（迄今为止已在 1500 多名患者中使用），并且不会遇到明显的特定吸收比限制、较差的组织对比度或像 3 T 下的自旋回波 T1 加权成像所遇到的运动伪影。
Rationale and Objectives:The objective of this study was to evaluate a 2-dimensional spoiled gradient echo (GRE) imaging approach using a very short in-phase TE for routine T1-weighted imaging of the brain at 3 T. Materials and Methods:Patient examinations were compared from a 3 T magnetic resonance (MR) unit located immediately adjacent to a similarly equipped 1.5 T unit. Pre- and postcontrast T1-weighted images were evaluated and compared at 1.5 versus 3 T with a 2-dimensional (2-D) spin echo sequence used at 1.5 T and a 2-D GRE sequence at 3 T. The 2 MR systems used are from the same vendor, use similar 8-channel coils, and use identical gradients. The T1-weighted GRE sequence, used at 3 T, relies on a short TE (2.4 ms) to limit flow-related and susceptibility artifacts. Region-of-interest analysis was performed on 16 different sagittal patient examinations at both field strengths (32 total) and similarly on 10 different pre- and postcontrast axial examinations (40 total). Four blinded neuroradiologists also evaluated these studies. Results:Using an off-midline sagittal slice depicting the caudate nucleus (signal-to-noise ratio [SNR] 163 ± 28 vs. 70 ± 7, 3 T vs. 1.5 T) and corona radiata (SNR 214 ± 35 vs. 82 ± 10), 3 T markedly outperformed 1.5 T in both SNR and contrast-to-noise ratio (CNR) (51 ± 14 vs. 12 ± 5). On axial imaging, despite a reduction in slice thickness (5 to 3 mm) and scan time (5 to 1 minute), there was no significant difference pre- or postcontrast in SNR and CNR comparing 3 and 1.5 T. On blinded film review, 3 T performed slightly better on sagittal scans than 1.5 T in regard to motion artifacts (reduced), gray-white matter differentiation, and overall image quality. On axial scans, 3 T performed markedly better in all 3 categories both pre- and postcontrast. In regard to overall image quality, 3 T was preferred 9:2 precontrast and 4:1 postcontrast. Conclusions:High-quality, thin-section (3-mm) T1-weighted imaging can be readily performed at 3 T using a short TE 2-D GRE technique. This approach offers superior SNR and CNR with reduced motion artifacts and scan time as compared with imaging at 1.5 T and is advocated for routine brain imaging at 3 T. It is robust (used in over 1500 patients to date) and does not experience significant specific absorption ratio limitations, poor tissue contrast, or accentuated motion artifacts like encountered with spin echo T1-weighted imaging at 3 T.