ULTRA-SENSITIVE MRI PROBES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 本研究项目的总体目标是开发超灵敏的磁共振探头。一种方法是基于MFe2O4(M=Fe，Co，Mn)负载的聚合物胶束用于癌症分子成像应用。常规磁共振造影剂的低灵敏度严重限制了它们在体内监测分子过程中的应用。另一种方法是使用超顺磁性氧化铁纳米颗粒(SPIO)。SPIO在分子成像、细胞跟踪和生物分子检测中的应用日益广泛，导致了新型SPIO配方和成像获取方法的快速发展。与低分子量、顺磁性金属络合物如Gd-DTPA(T1造影剂)相比，SPIO纳米颗粒被认为是T2负性造影剂，具有显著更高的T1和T2弛豫度。传统上，SPIO颗粒通过T2或T2*加权磁共振成像来评估其对水信号的消相能力。高SPIO浓度下的图像空洞和增强前扫描的要求限制了SPIO检测的准确性和特异性。最近的一个目标是开发和应用一种非共振饱和(ORS)方法，以允许对负载SPIO的聚合物胶束进行开关成像，用于实体肿瘤的分子成像。RR提供了4.7T，这是我们的主力。最初的成像是由任继民博士进行的，得到了研究资源的支持。任博士培养了两名博士后研究员查理·克姆通博士和蔡斯·克辛格博士，现在所有的成像都由高博士的团队进行。

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. The general objective of this research project is to develop ultra-sensitive MRI probes. One approach is based on MFe2O4 (M=Fe, Co Mn)-loaded polymer micelles for cancer molecular imaging applications. The low sensitivity of conventional MR contrast agents severely limits their use for monitoring molecular processes in vivo. Another approach is to used superparamagnetic iron oxide nanoparticles (SPIO). The growing use of SPIO in molecular imaging, cell tracking and biomolecular detection has resulted in the rapid development of novel SPIO formulations and imaging acquisition methods. Compared to the low molecular weight, paramagnetic metal chelates such as Gd-DTPA (T1 contrast agent), SPIO nanoparticles are considered T2-negative contrast agents with substantially higher T1 and T2 relaxivity. Conventionally, SPIO particles are evaluated by T2- or T2*-weighted MR imaging for their abilities in dephasing water signals. Image void at high SPIO concentrations and requirement of a pre-contrast scan limit the accuracy and specificity for SPIO detection. A recent objective is to develop and apply an off-resonance saturation (ORS) method to allow for on-and-off imaging of ¿v¿3-targeted SPIO-loaded polymeric micelles for molecular imaging of solid tumors. The RR has provided access to the 4.7 T, the workhorse for us. Iniitially the imaging was performed by Dr. Jimin Ren, supported by the Research Resource. Dr. Ren trained two post - doctoral fellows, Drs. Charlie Khemtong and Chase Kessinger, and now all imaging is performed by Dr. Gao's team.