Obata Takayuki, Uemura Koji, Nonaka Hiroi, Tamura Mitsuru, Tanada Shuji, Ikehira Hiroo
Department of Medical Imaging, National Institute of Radiological Sciences, Chiba 263-8555, Japan.
Magn Reson Imaging. 2006 Jan;24(1):97-101. doi: 10.1016/j.mri.2005.10.011. Epub 2005 Dec 19.
To acquire high-resolution magnetic resonance (MR) images, we developed a new blinking artifact reduced pulse (BARP) sequence with a surface coil specialized for microscopic imaging (47 mm in diameter).
To reduce eye movement, we ascertained that the subjects' eyes were kept open and fixated to the target in the 1.5-T MR gantry. To reduce motion artifacts from blinking, we inserted rest periods for blinking (1.5 s within every 5 s) during MR scanning (T2-weighted fast spin echo; repetition time, 5 s; echo time, 100 ms; echo train, 11; matrix, 256 x 128; field of view, 5 cm; 1-mm thickness x 30 slices). Three scans (100 s x 3) were performed for each normal subject, and they were added together after automatic adjustment for location to reduce quality loss caused by head motion.
T2-weighted MR images were acquired with a high resolution and a high signal-to-noise ratio. Motion artifacts were reduced with BARP, as compared with those with random blinking. Intraocular structures such as the iris and ciliary muscles were clearly visualized. Because the whole eye can be covered with a 1-mm thickness by this method, three-dimensional maps can easily be generated from the obtained images.
The application of BARP with a surface coil of the human eye might become a useful and widely adopted procedure for MR microimaging.
为获取高分辨率磁共振（MR）图像，我们开发了一种新的减少闪烁伪影脉冲（BARP）序列，该序列采用专门用于显微成像的表面线圈（直径47毫米）。
为减少眼球运动，我们确定在1.5-T MR扫描架内让受试者眼睛保持睁开并注视目标。为减少眨眼产生的运动伪影，我们在MR扫描期间（T2加权快速自旋回波；重复时间5秒；回波时间100毫秒；回波链11；矩阵256×128；视野5厘米；层厚1毫米×30层）插入眨眼休息时间（每5秒内1.5秒）。对每位正常受试者进行三次扫描（100秒×3），并在自动调整位置后将它们相加，以减少头部运动导致的质量损失。
获得了具有高分辨率和高信噪比的T2加权MR图像。与随机眨眼相比，BARP减少了运动伪影。虹膜和睫状肌等眼内结构清晰可见。由于用这种方法整个眼睛可以被1毫米的厚度覆盖，因此可以很容易地从获得的图像生成三维图谱。
将BARP与眼表面线圈结合应用可能成为MR显微成像中一种有用且广泛采用的方法。
