T2*-WEIGHTED IMAGES OF THE HUMAN BRAIN DURING HYPEROXIA

高氧期间人脑的 T2* 加权图像

• 批准号: 8169071
• 负责人: David Pilkinton
• 金额: $ 3.47万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8169071
• 关键词: Arteries; Blood; Blood Volume; Brain; Brain region; Cerebrum; Computer Retrieval of Information on Scientific Projects Database; Functional Magnetic Resonance Imaging; Funding; Grant; Hemoglobin; Human; Hyperoxia; Image; Inferior; Institution; Molecular; Oxygen; Plasma; Research; Research Personnel; Resources; Signal Transduction; Source; United States National Institutes of Health; Venous; Weight; brain tissue; feeding; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Hyperoxic contrast (increasing the inspired fraction of oxygen >21%) produces positive contrast enhancement in T2*-weighted images in brain tissue and has been used to calculate cerebral blood volume and to standardize signal changes in BOLD fMRI experiments. The increase in venous blood oxygenation is due to excess dissolved oxygen carried in the plasma of arterial blood, which during hyperoxia contains completely saturated hemoglobin. While it is known that molecular oxygen is paramagnetic and that increased concentrations significantly reduce T1, the effect in heavily T2*-weighted images is generally considered to be negligible when compared to the effects of BOLD contrast, especially at low FiO2 levels. We have found in our preliminary studies using hyperoxic contrast in a whole brain EPI study at 3T that, although positive contrast enhancement dominates most regions, the inferior regions of the brain show significant negative contrast enhancement in strongly T2*-weighted images, even at low oxygen concentration (FiO2<0.6). These regions showing negative contrast have a relatively high fraction of arterial cerebral blood volume, since they contain large arteries that feed the brain. We believe that this negative contrast is at least in part due to the shortening of T2* in arterial blood due excess paramagnetic molecular oxygen dissolved in the plasma.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 高氧造影剂（增加吸入氧气分数>21%）产生阳性造影剂 在脑组织中的T2* 加权图像的增强，并已被用来计算脑 血容量和标准化信号变化在BOLD功能磁共振成像实验。 的增加 静脉血液氧合是由于动脉血液的血浆中携带的过量溶解氧。 血液，在高氧期间包含完全饱和的血红蛋白。 虽然已知 分子氧是顺磁性，且增加浓度显著降低 T1时，在重T2* 加权图像中的影响通常被认为是可忽略的， 与BOLD对比的效果相比，尤其是在低FiO 2水平下。 我们在我们的 在3 T全脑EPI研究中使用高氧造影剂的初步研究，尽管 正对比度增强占主导地位的大部分地区，大脑的下部区域显示， 在强T2* 加权图像中显著的负对比度增强，即使在低T2 * 加权图像中， 氧浓度（FiO 2 <0.6）。 这些显示负对比度的区域具有相对的 高比例的动脉脑血容量，因为它们含有大动脉， 个脑袋 我们认为，这种负对比至少部分是由于T2* 缩短， 动脉血由于过量的顺磁性分子氧溶解在血浆中。