Yoneyama Masami, Nakamura Masanobu, Obara Makoto, Namiki Takashi, Takemura Atsushi, Tatsuno Satoshi, Sawano Seishi
Yaesu Clinic, C-road Bldg 4F, 2-1-18 Nihonbashi, Chuo-ku, Tokyo, Japan,
Radiol Phys Technol. 2014 Jan;7(1):167-75. doi: 10.1007/s12194-013-0247-9. Epub 2013 Dec 4.
We propose a simple scheme of 3D turbo spin echo (TSE) with low-refocusing flip angles (RFAs) for obtaining sufficient T1-weighted contrast. The low RFA can easily lead spins into a pseudo-steady-state (PSS) condition, but a preparation scheme is required for smooth transition into static PSS. For obtaining T1 contrast, PSS preparation is the most important factor, and therefore we focused on the PSS preparation. To optimize the T1 contrast in the proposed sequence, we compared the following parameters: RFAs of 90° and 30°, and a PSS preparation scheme of "90° + α/2" and asymptotic preparation. Subsequently, to demonstrate the quality of the proposed sequence, we compared the image quality regarding conventional 3D TSE and 2D spin echo (SE). A combination of an RFA of 30° and the "90° + α/2" preparation scheme showed the highest T1 contrast. The optimized sequence provided higher contrast and sharper images compared to 3D TSE, and it showed contrast and a signal-to-noise ratio similar to those of 2D SE.
我们提出了一种采用低重聚焦翻转角(RFA)的三维快速自旋回波(TSE)简单方案,以获得足够的T1加权对比度。低RFA很容易使自旋进入伪稳态(PSS)状态,但需要一种准备方案才能平稳过渡到静态PSS。为了获得T1对比度,PSS准备是最重要的因素,因此我们专注于PSS准备。为了在所提出的序列中优化T1对比度,我们比较了以下参数:90°和30°的RFA,以及“90° + α/2”的PSS准备方案和渐近准备。随后,为了证明所提出序列的质量,我们比较了关于传统三维TSE和二维自旋回波(SE)的图像质量。30°的RFA与“90° + α/2”准备方案的组合显示出最高的T1对比度。与三维TSE相比,优化后的序列提供了更高的对比度和更清晰的图像,并显示出与二维SE相似的对比度和信噪比。