New PET/MRI Probe Enables Early Detection of Difficult-to-Detect Diseases

By MedImaging International staff writers
Posted on 06 Aug 2024

Image: Current PET/MRI imaging of healthy and damaged mouse kidneys using the dual contrast agent [18F][Gd(FL1)] (Photo courtesy of IOCB Prague)

Medicine has long searched for ways to enhance imaging techniques, aiming to integrate the advantages of magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI excels in imaging internal organs and tissues rich in water content, while PET can detect minute quantities of substances, making it adept at identifying molecular markers in cancer cells. Merging these technologies posed a challenge due to the intense magnetic fields of MRI, which interfere with PET's electronic functions. However, this obstacle has been overcome with the emergence of hybrid PET/MRI machines in clinical settings. The next hurdle was creating a dual-purpose contrast agent suitable for both PET and MRI. Now, a new hybrid contrast agent has properties that make it the first serious candidate for a PET/MRI agent usable in a clinical setting.

A research team from IOCB Prague (Prague, Czech Republic), working in collaboration with the University of Tübingen (Tübingen, Germany), and the Faculty of Science, Charles University (Prague, Czech Republic) , has developed a pioneering contrast agent usable in both MRI and PET. The simple and effective approach published in Angewandte Chemie could greatly improve the diagnosis and treatment of conditions like kidney diseases and tumors. Earlier efforts to create PET/MRI probes often resulted in complex molecules with challenging synthesis and limited use. The team simplified this by developing a versatile molecule, easy to understand and use by radiologists, maintaining all beneficial properties of standard MRI contrast agents while also providing PET imaging capabilities.

The new solution is a molecule that cleverly combines gadolinium and radioactive fluorine-18, a staple in medical imaging easily accessible for use. Addressing the challenge of the vast difference in the amounts required for MRI and PET, the research team innovated by substituting nonradioactive fluorine atoms in the MRI contrast agent with radioactive fluorine-18. This process is both fast and efficient, allowing automated synthesis to produce sufficient agent for five patients in under 30 minutes. During testing in a mouse model, this agent unexpectedly revealed kidney issues in a seemingly healthy mouse. The diseased kidney displayed filtration patterns only detectable through the combined power of PET and MRI, highlighting the agent's ability to noninvasively monitor the biochemical behavior, distribution, and accumulation in real time, providing invaluable diagnostic insights.

“This method represents a pioneering step toward personalized diagnostics, showcasing the significant diagnostic potential of our hybrid molecule,” said Prof. André Ferreira Martins at the University of Tübingen. “This is a revolutionary discovery in the field of precise imaging. We are on a path that will eventually allow us to determine not only what disease a patient has but also the stage, type, and aggressiveness of the condition.”