NEW METHOD FOR MRI BASED ON DETECTION OF INTERMOLECULAR ZERO QUANTUM COHERENCES

基于分子间零量子相干性检测的MRI新方法

• 批准号: 6121056
• 负责人: RAHIM R RIZI
• 金额: $ 1.35万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 1999-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6121056
• 关键词: biomedical resource; magnetic resonance imaging; technology /technique

Contrast in MRI is largely based on variations in spin density or relaxation times, sometimes enhanced by injected contrast agents such as gadolinium compounds. The relationship between these parameters and tissue morphology is not always unique. Thus it is not surprising that in some applications no combination of these parameters gives sufficient useful contrast. Even with brain imaging, particularly in the rapidly expanding field of functional MRI, contrast is frequently the limiting factor. New methods for contrast enhancement could thus improve soft tissue characterization, particularly if they correlate with physiologically important characteristics. Here we demonstrate a new type of MRI based on detection of "impossible" intermolecular multiple-quantum coherences (iMQCs), specifically the zero-quantum coherences (iZQCs) which correspond to simultaneously flipping two water spins in opposite directions on molecules separated by 10mm to1 mm. The iZQC linewidth (hence the image contrast) is determined by local susceptibility variations. These variations are physiologically important (for example, they are affected by tissue oxygen gradients in vivo) but are not directly measured by other imaging methods. We have obtained phantom images and in the process of extending this work to human studies. We expect that contrast generated by iZQC might be useful in the detection of small tumor since susceptibility correlates with oxygen concentration.

MRI 中的对比度很大程度上取决于自旋密度或 弛豫时间，有时通过注射造影剂来增强，例如 作为钆化合物。 这些参数之间的关系 并且组织形态并不总是唯一的。 因此这并不奇怪 在某些应用中，这些参数的组合无法给出 足够的有用对比。 即使有脑成像，特别是在 随着功能性 MRI 领域的迅速扩展，对比技术经常被 限制因素。 因此，对比度增强的新方法可以 改善软组织特征，特别是当它们相关时 具有重要的生理特征。 这里我们演示一个 基于检测“不可能”分子间相互作用的新型MRI 多量子相干性（iMQC），特别是零量子相干性 相干性（iZQC）对应于同时翻转两个 水在相隔 10mm to1 的分子上以相反方向旋转 毫米。 iZQC 线宽（因此图像对比度）由下式确定 局部敏感性差异。 这些变化是生理上的 重要（例如，它们受到组织氧梯度的影响 体内），但不能通过其他成像方法直接测量。 我们 已经获得了幻影图像，并且正在扩展这项工作 到人类研究。 我们预计 iZQC 生成的对比度可能是 由于敏感性相关，因此可用于检测小肿瘤 与氧气浓度。