A probe for specimen magnetic resonance microscopy.
A probe for specimen magnetic resonance microscopy.
复制标题
用于标本磁共振显微镜的探针。
DOI：
10.1097/00004424-199202000-00013
复制
发表时间：
1992
影响因子：
6.7
通讯作者：
Johnson,GA
中科院分区：
文献类型：
--
作者：
Banson,ML;Cofer,GP;Black,R;Johnson,GA
在磁共振（MR）显微镜中，空间分辨率的主要限制之一是有限的信号。本研究的目的是建立一个射频（rf）探针，用于300 MHz固定标本的磁共振显微镜。探头的设计准则为(1)高灵敏度；(2)射频均匀性好；(3) Bo变化最小化。所有探针都是工作频率为300 MHz的亥姆霍兹对。线圈由铜/聚四氟乙烯/铜微波衬底构成，消除了焊料和分立电容器的敏感性问题。并与传统螺线管的信噪比进行了比较。用琼脂凝胶和盐水填充管的模型来表征信噪比和均匀性。线圈对的信噪比测量结果显示，与参考螺线管相比，线圈对的信噪比有了显著改善（高达60%）。均匀性区域定义为信号强度变化10%。这与线圈的内径有关。信噪比与直径、分离和铜箔宽度的关系图允许对结构进行优化。使用这种线圈，现在可以对像素小至20 x 20 x 30[微米]m的小型固定标本进行MR显微镜检查。目前正在利用该探针提供的信噪比和均匀性来确定MR显微镜可能增加病理学家诊断工具的程度。
One of the primary limits to spatial resolution in magnetic resonance (MR) microscopy is the limited signal. The purpose of this study is to build a radiofrequency (rf) probe for MR microscopy of fixed specimens at 300 MHz. The design criteria for the probe were (1) high sensitivity;(2) good rf homogeneity;(3) minimization of Bo variations. All probes were Helmholtz pairs operating at 300 MHz. Coils were constructed from copper/Teflon/copper microwave substrate which eliminated susceptibility problems from solder and discrete capacitors. Signal-to-noise ratio (SNR) was compared with a conventional solenoid. Phantoms of agar gels and saline-filled tubes were used to characterize the SNR and homogeneity. SNR measurements of the coil pairs showed a marked improvement (up to 60%) over that of the reference solenoid. The region of homogeneity was defined as a 10% variation in signal intensity. This correlated with the coil's inner diameter. Graphs of SNR versus diameter, separation, and copper foil width allowed for optimization of the structure. Using this coil, MR microscopy is now possible on small, fixed specimens with pixels as small as 20 x 20 x 30 [micro] m. Work is currently under way exploiting the SNR and homogeneity provided by this probe to determine the degree to which MR microscopy might add to the pathologists' diagnostic tools.