MRI model magnet with an off-centered homogeneous field zone for Benton visual retention test

磁共振成像（MRI）需要一个高度均匀的磁场区，通常出现在MRI磁线圈的轴向中心。如果允许这种均匀区出现在沿线圈轴线偏离中心的位置，MRI的新应用可能会成为可能。为了验证这一想法，我们制作了一个具有偏心均匀场区的模型磁铁。作为这类MRI应用的一个例子，我们考虑了一种基于功能MRI的Benton视觉保留测试，该测试目前被用于痴呆症。

Magnetic resonance imaging (MRI) requires a highly homogenous magnetic field zone which usually appears at the axial center of the MRI magnet coil. If this homogeneous zone is allowed to occur at an off-centered position along the coil axis, quite new applications of MRI may be possible. In order to examine this idea, we fabricated a model magnet with an off-centered homogeneous field zone. As an example of application of this type of MRI, we consider a functional-MRI-based Benton visual retention test which is currently adopted on dementia.