QUANTITATIVE ASSESSMENT OF IRON OVERLOAD BY MRI

通过 MRI 定量评估铁过载

• 批准号: 6044046
• 负责人: ZHIYUE J WANG
• 金额: $ 19.6万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 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 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6044046
• 关键词: bioimaging /biomedical imaging; blood transfusion; clinical research; gerbil /jird; heart metabolism; human subject; human tissue; iatrogenic disease; iron poisoning; liver metabolism; magnetic resonance imaging; metal metabolism; method development; noninvasive diagnosis

DESCRIPTION (Adapted from applicant's abstract) The long-term objective of this proposal is to develop in vivo magnetic resonance (MR) techniques for a reliable non-invasive assessment of iron stores in patients with iron overload due to chronic transfusion therapy for diseases such as thalassemia, sickle cell disease and other blood disorders. The specific aims of the project are: 1a) to study the T2 of liver tissue under iron overload conditions in vivo and correlate with biopsy determined iron level; 1b) to measure T2 of cardiac tissue from autopsied human hearts and an iron overload gerbil model in vitro and correlate with a chemically determined iron level; 2) to assess a new, non-invasive magnetic susceptibility measurement technique, "the contact reference method," that will be applicable for outer myocardium; (3) to develop a non-invasive susceptibility measurement technique for the liver using blood vessel signal as internal reference. An accurate assessment of body iron stores plays a central role in the management of chronically-transfused patients. Current body iron assessment methods are limited to liver biopsy or superconducting quantum interference device (SQUID) susceptometry, but neither is convenient for routine use, and there is no non-invasive technique to evaluate the heart. The focus of this application centers on developing techniques for the liver examination, and characterizing MR properties of heart tissue under iron overload conditions. A spectroscopy sequence with minimum TE 1.5 ms will be used to measure the liver T2 in a 3x3x3 cm3 volume in 30 patients, and correlate the results with biopsy determine iron level; In vitro T2 of 108 specimens from 9 human autopsy hearts and 192 specimens from 48 gerbil hearts will be measured and correlated with the tissue iron level. The magnetic susceptibility of the same human autopsy hearts and gerbil hearts will be evaluated by a contact reference technique: the resonant frequency differences across the interface of tissue and saline reference, obtained by using 3-dimensional gradient echo imaging, will be used to qualify the tissue susceptibility. Finally, an in vivo liver susceptibility measurement technique will be developed: sequential 2-dimensional navigator echo imaging will be used to measure frequency offset, the magnetic susceptibility of the liver will be obtained. For each aim, statistical analysis using linear regression will be done to assess the reliability of iron level predicted by the MR technique.

描述 （改编自申请人的摘要）该提案的长期目标 是开发体内磁共振（MR）技术以获得可靠的 对铁超负荷患者的铁储备进行无创评估 地中海贫血、镰状细胞病等疾病的长期输血治疗 疾病和其他血液疾病。 该项目的具体目标是： 1a) 研究体内铁超载条件下肝组织的T2 并与活检确定的铁水平相关； 1b) 测量 T2 来自尸检人体心脏的心脏组织和铁超载沙鼠模型 体外并与化学测定的铁水平相关； 2）评估 一种新的非侵入性磁化率测量技术“ 接触参考法”，适用于外层心肌；(3) 开发肝脏无创敏感性测量技术 使用血管信号作为内部参考。 准确的评估 身体铁储备在管理中发挥着核心作用 长期输血的患者。 目前体内铁的评估方法有 仅限肝活检或超导量子干涉装置 （SQUID）电纳测定法，但这两种方法都不方便常规使用，并且有 不是评估心脏的非侵入性技术。 本次的重点 应用中心是开发肝脏检查技术，以及 表征铁过载条件下心脏组织的 MR 特性。 TE 最小为 1.5 ms 的光谱序列将用于测量 30 名患者的 3x3x3 cm3 体积中的肝脏 T2，并将结果关联起来 通过活检确定铁水平； 9 人 108 个样本的体外 T2 将测量尸检心脏和来自 48 只沙鼠心脏的 192 个标本 与组织铁水平相关。 磁化率 相同的人体尸检心脏和沙鼠心脏将由联系人进行评估 参考技术：谐振频率差异 组织和盐水参考的界面，通过使用 3 维获得 梯度回波成像将用于鉴定组织磁化率。 最后，体内肝脏敏感性测量技术将是 开发：连续二维导航回波成像将用于 测量频率偏移，肝脏的磁化率将为 获得。 对于每个目标，使用线性回归的统计分析将 评估 MR 预测的铁水平的可靠性 技术。