近日，德国基尔大学Rainer Herges课题组提出了用于绝对3D温度磁共振成像的光开关造影剂。 相关论文于2021年2月19日发表在《德国应用化学》杂志上。

在这项研究中，课题组人员提出了一项MRI造影剂(CA)用于绝对且浓度无关的温度成像的原理证明研究。这些CAs是基于偶氮咪唑取代的Ni(II)卟啉，它可以在溶液中进行光驱动配位诱导的自旋状态切换(LD - CISSS)。使用常规的临床磁共振成像序列监测反向异构化（顺式到反式）的快速一阶动力学，可以确定其半衰期，从而直接转化为绝对温度。

科研人员以不同的温度响应的CA作为原型，成功在基于甲醇的凝胶中进行了测试，并创建了具有高空间分辨率（0.13 x 0.13 x 1.1 mm）和低温度误差（< 0.22 °C）的梯度幻影的温度图谱。该方法足够快，可以记录来自例如薄膜的热源的温度流。

据了解，温度可以作为组织代谢的临床标志物和炎症或肿瘤的检测。磁共振成像(MRI)用于无创监测体温等生理参数的应用正在稳步上升。

附：英文原文

Title: Towards Photoswitchable Contrast Agents for Absolute 3D Temperature MR Imaging

Author: Rainer Herges, Vanessa Wellm, Jens Groebner, Gernot Heitmann, Frank Soennichsen

Issue&Volume: 2021-02-19

Abstract: Temperature can be used as clinical marker for tissue metabolism and the detection of inflammations or tumors. The use of magnetic Resonance Imaging (MRI) for monitoring physiological parameters like the temperature noninvasively is steadily increasing. In this study, we present a proof‐of‐principle study of MRI contrast agents (CA) for absolute and concentration independent temperature imaging. These CAs are based on azoimidazole substituted Ni(II) porphyrins, which can undergo Light‐Driven Coordination‐Induced Spin State Switching (LD‐CISSS) in solution. Monitoring the fast first order kinetic of back isomerisation (  cis  to  trans  ) with standard clinical MR imaging sequences allows the determination of half‐lives, that can be directly translated into absolute temperatures. Different temperature responsive CAs were successfully tested as prototypes in methanol‐based gels and created temperature maps of gradient phantoms with high spatial resolution (0.13 x 0.13 x 1.1 mm) and low temperature errors (< 0.22 °C). The method is sufficiently fast to record the temperature flow from a heat source as a film.

DOI: 10.1002/anie.202015851

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202015851