FAST MULTISLICE B1 MAPPING: MRI

快速多切片 B1 映射：MRI

• 批准号: 6309981
• 负责人: SIMON TOPP
• 金额: $ 1.55万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6309981
• 关键词: Mammalia; bioimaging /biomedical imaging; biomedical resource; magnetic resonance imaging; radiology; technology /technique

Introduction: Inhomogeneity of the applied B1 field compromises the accuracy of MR-measurements. The inhomogeneity depends on the RF-coil, the load, and characteristics of the observed object [1]. A map of the B1 field makes it possible to account for and correct problems associated with the RF-inhomogeneity, such as image artifacts or inaccurate quantization. Methods: In our method, a stimulated echo sequence (STE) is modified with an additional non-selective pulse. Due to the simple relationship between the observed signal and the flip angle, theta, of the extra pulse, we can robustly estimate B1. Multislice B1-maps were measured on a 1.5-T GE Signa system using the standard circularly polarized head coil. A 28-cm diameter sphere containing doped water was placed in the center of the RF-coil. Four sets of 7 slices were acquired with the nominal theta set to 0, 100, 200, and 300 degrees. Total imaging time was 2:20 min. Results: Multislice quantitative B1 maps were acquired from phantoms and normal volunteers. The maps confirm the exptected B1 variations of the head coil. Conclusions: Rapid quantitative volumetric estimates of RF profiles can be calculated from acquisitions with a modified stimulated-echo sequence.

简介：应用B1场妥协的不均匀性 MR测量的准确性。 不均匀性取决于 RF线圈，观察到的对象的负载和特性[1]。 一个 B1字段的地图使得有可能考虑并更正 与RF侵入性相关的问题，例如图像伪像 或量化不准确。 方法：在我们的方法中，刺激了 回声序列（Ste）通过其他非选择性修改 脉冲。 由于观察到的信号和 额外脉搏的翻转角度，theta，我们可以稳健地估计 B1。 使用Multislice B1-MAP在1.5-T GE Signa系统上测量 标准的圆形式头圈。 直径28厘米 含有掺杂水的水放在RF线圈的中心。 四个 将7个切片集获得，名义theta设置为0、100， 200和300度。 总成像时间为2:20分钟。 结果： 从幻影和正常地获取了多层定量B1地图 志愿者。 地图证实了头部的B1变化 线圈。 结论：RF的快速定量体积估计值 配置文件可以通过修改的收购来计算 刺激回波序列。