Molecular imaging aims at the use of imaging probes to visualize specific cellular or sub cellular processes that occur before changes in morphology and function. This is highly relevant because impairments of such processes often are precursors or earliest stages of cardiovascular disease. They are also involved in the early response to therapy or may identify candidates most suitable for a specific therapy. Probes for multiple molecular pathways, including cardiac metabolism, cell death, neurotransmission, receptors, cell-matrix interaction and cell trafficking have been developed in early experimental work and are increasingly translated into the clinical arena.
Several different imaging techniques can be used for detection of molecular probes, including nuclear imaging, magnetic resonance imaging, ultrasound and optical imaging, although nuclear imaging techniques, and especially positron emission tomography (PET) are currently most promising because of their superior sensitivity for detection of small amounts of highly specific radioactive molecular probes in the body. The new generation of hybrid imaging system, which integrate PET with X-ray computed tomography (CT) will further refine the application of molecular imaging probes, because co registration with a high-resolution CT will allow for better localization of the specific molecular signal from PET.
Applications that are currently being tested in early clinical stages include the identification of individuals at risk for atherosclerotic plaque rupture, identification of risk for development of heart failure and/or fatal ventricular arrhythmia, and monitoring of novel therapies such as stem cell therapy or gene delivery.
The field is still in its infancy and strong translational efforts need to continue to make it a clinical reality in the next years. But there is a strong notion that, in the future era of personalized molecular medicine, molecular imaging will play a key role for guidance of clinical decision making based on individual disease biology.