Hayashi Takafumi, Wada Akihiko, Uchida Nobue, Kitagaki Hajime
Department of Radiology, Shimane University Faculty of Medicine, Izumo, Shimane, Japan.
Magn Reson Med Sci. 2009;8(1):33-8. doi: 10.2463/mrms.8.33.
Imaging diagnosis of Alzheimer disease (AD), the leading cause of dementia, requires evaluation of the extent of hippocampal atrophy. Coronal magnetic resonance (MR) images of patients with AD often demonstrate outward rotation of the hippocampus that is altered from a long horizontal elliptical to a long vertical elliptical shape. Such rotation may be related to the disease process of AD.
To determine whether hippocampal rotation is associated with AD, we investigated MR images from 11 patients with AD and 11 normal controls, measuring the hippocampal angle (HA) and the volume of the left hippocampus on coronal T(1)-weighted MR images. The HA is the angle between a horizontal line orthogonal to the falx cerebri and the uncal sulcus line between the deepest point of the uncal sulcus and the point nearest to the side of the ambient cistern in the uncal gyrus facing the uncal sulcus. The HA is measured on the most rostral slice in which the uncal sulcus can be identified and increases with hippocampal rotation.
We found correlation between the HA and standardized hippocampal volume in the AD group, but not in controls.
Hippocampal rotation is a new marker associated with the pathology of AD.
作为痴呆症的主要病因，阿尔茨海默病（AD）的影像学诊断需要评估海马萎缩的程度。AD患者的冠状磁共振（MR）图像常常显示出海马的向外旋转，即从长水平椭圆形变为长垂直椭圆形。这种旋转可能与AD的疾病进程有关。
为了确定海马旋转是否与AD相关，我们研究了11例AD患者和11名正常对照者的MR图像，在冠状T（1）加权MR图像上测量海马角（HA）和左侧海马的体积。HA是与大脑镰正交的水平线与钩回沟最深点和面对钩回沟的钩回中最靠近环池侧的点之间的钩回沟线之间的夹角。HA在可识别钩回沟的最靠前层面上测量，且随着海马旋转而增大。
我们发现AD组中HA与标准化海马体积之间存在相关性，而对照组中不存在这种相关性。
海马旋转是与AD病理学相关的一个新标志物。
