Desbrée A, Rbah L, Langlois J-B, Grenier D, Mastrippolito R, Pain F, Pinot L, Lanièce P, Zimmer L, Gurden H
IRSN, BP 17, 92262, Fontenay aux roses, France.
Eur J Nucl Med Mol Imaging. 2007 Nov;34(11):1868-72. doi: 10.1007/s00259-007-0475-5. Epub 2007 Jun 27.
Multimodal instrumentation is a new technical approach allowing simultaneous and complementary in vivo recordings of complementary biological parameters. To elucidate further the physiopathological mechanisms in intact small animal models, especially for brain studies, a challenging issue is the actual coupling of magnetic resonance imaging (MRI) techniques with positron emission tomography (PET): it has been shown that running the technology for radioactive imaging in a magnet alters the spatiotemporal performance of both modalities. Thus, we propose an alternative coupling of techniques that uses the beta-MicroProbe instead of PET for local measurements of radioactivity coupled with MRI.
We simultaneously recorded local radioactivity due to [(18)F]MPPF (a 5-HT(1A) receptor PET radiotracer) binding in the hippocampus with the beta-MicroProbe and carried out anatomical MRI in the same anaesthetised rat.
The comparison of [(18)F]MPPF kinetics obtained from animals in a magnet with kinetics from a control group outside the magnet allowed us to determine the stability of tracer biokinetic measurements over time in the magnet. We were thus able to show that the beta-MicroProbe reliably measures radioactivity in rat brains under an intense magnetic field of 7 Tesla.
The biological validation of a beta-MicroProbe/MRI dual system reported here opens up a wide range of future multimodal approaches for functional and pharmacological measurements by the probe combined with various magnetic resonance technologies, including anatomical MRI, functional MRI and MR spectroscopy.
多模态仪器是一种新的技术方法，可同时对互补的生物学参数进行体内记录并相互补充。为了进一步阐明完整小动物模型中的生理病理机制，特别是对于脑部研究，一个具有挑战性的问题是磁共振成像（MRI）技术与正电子发射断层扫描（PET）的实际结合：已表明在磁体中运行放射性成像技术会改变这两种模态的时空性能。因此，我们提出了一种技术的替代结合方式，即使用β-微探针代替PET来进行与MRI相结合的局部放射性测量。
我们使用β-微探针同时记录了麻醉大鼠海马体中因[(18)F]MPPF（一种5-HT(1A)受体PET放射性示踪剂）结合而产生的局部放射性，并进行了解剖学MRI。
将磁体中的动物获得的[(18)F]MPPF动力学与磁体外部对照组的动力学进行比较，使我们能够确定示踪剂生物动力学测量在磁体中随时间的稳定性。因此，我们能够证明β-微探针在7特斯拉的强磁场下能够可靠地测量大鼠脑中的放射性。
本文报道的β-微探针/MRI双系统的生物学验证为通过该探针结合各种磁共振技术（包括解剖学MRI、功能MRI和磁共振波谱）进行功能和药理学测量开辟了广泛的未来多模态方法。
