Fujita N, Tanaka H, Takanashi M, Hirabuki N, Abe K, Yoshimura H, Nakamura H
Department of Radiology, Osaka University Medical School, Osaka, Japan.
AJNR Am J Neuroradiol. 2001 Oct;22(9):1719-26.
MR imaging has the potential capacity for noninvasively depicting the anatomy and function of thalamic nuclei. The purpose of this study was to identify the lateral geniculate nucleus (LGN), which is the thalamic relay nucleus for vision, with anatomic and functional MR imaging at 1.5 T.
Three-millimeter-thick axial images were obtained from eight volunteers by using a double-echo turbo spin-echo sequence for proton density- and T2-weighted contrast and a spin-echo 3D gradient-echo sequence for T1-weighted contrast. Each participant underwent a visual activation experiment using gradient-echo echo-planar imaging at the same location as that of the anatomic study.
In all cases, the LGN was recognized on proton density-weighted images as a small wedge-shaped area of high signal intensity relative to that of the surrounding white matter tracts. However, it was difficult to identify the LGN on T1- and T2-weighted images because of the smaller contrast-to-noise ratios between the LGN and the adjacent white matter tracts, compared with those of proton density-weighted images (P <.001). Bilateral thalamic activation and activation in the occipital cortex were shown in all participants. Each region of thalamic activation (23 +/- 3 mm2) was localized to the anatomically identified LGN.
The excellent correspondence between the anatomically and functionally identified LGN confirms that MR imaging is an indispensable method for visualizing functional neuroanatomy in thalamic nuclei.
磁共振成像（MR成像）具有无创描绘丘脑核团解剖结构和功能的潜在能力。本研究的目的是利用1.5T的解剖和功能磁共振成像识别外侧膝状体核（LGN），它是视觉的丘脑中继核。
对8名志愿者采用双回波快速自旋回波序列获取3毫米厚的轴向图像，用于质子密度加权和T2加权对比，采用自旋回波三维梯度回波序列用于T1加权对比。每位参与者在与解剖学研究相同的位置进行视觉激活实验，使用梯度回波平面回波成像。
在所有病例中，LGN在质子密度加权图像上被识别为相对于周围白质束呈高信号强度的小楔形区域。然而，由于与质子密度加权图像相比，LGN与相邻白质束之间的对比噪声比更小，因此在T1加权和T2加权图像上很难识别LGN（P<.001）。所有参与者均显示双侧丘脑激活和枕叶皮质激活。丘脑激活的每个区域（23±3平方毫米）定位于解剖学上确定的LGN。
解剖学和功能学上确定的LGN之间的良好对应证实，MR成像是可视化丘脑核团功能神经解剖结构的不可或缺的方法。
