1Bracco Suisse SA, Geneva Research Centre and Manufacturing Site, 1228 Plan Les Ouates, Switzerland
Ultrasound Contrast Agents (UCA) have been approved for clinical use in cardio-vascular and non cardio-vascular indications more than ten years ago. Its introduction prompted tremendous research efforts by clinicians, scientists and manufacturers. The advent of the so-called contrast-specific imaging techniques (e.g. Pulse Inversion, Amplitude Modulation and CPS) helped the field of contrast-enhanced ultrasound (CEUS) to mature and evolve considerably. It has made ultrasound a serious competitor with other imaging modalities, like CT and MR, for which contrast agents have been used for many years. Moreover, CEUS has been recognized as a low cost technique, which is easily available, uses no ionizing radiation, and is relatively safe with the absence of contra-indications such as COPD, renal or liver insufficiency. However, the general acceptance of CEUS still remains poor, and its utilization is limited to expert centers. The main problem with CEUS is that some barriers to its use must be overcome, such as: limited number of training programs, lack of approval for new indications (e.g. myocardial perfusion, prostate cancer…), lack of any reimbursement in most countries, limited number of large-scale multicenter trials, limited coordinated efforts from ultrasound and pharma companies to tackle issues like standardization and quantification, cross platform reproducibility, large dominance of radiologists in imaging for non cardio-vascular indications with possible conflicts between the available modalities, lack of workflow standardization for implementing CEUS in an ultrasound department. Those barriers could be overcome by coordinating efforts in providing evidence to health authorities and physicians, organizing training programs, standardization / automation of acquisition protocols (guidelines), volumetric acquisitions for subsequent analysis etc.
CEUS has proven to be a robust and powerful technique in expert hands but now it has to be translated into routine practice in all ultrasound departments. It will have a significant impact on healthcare cost with a real benefit for developed countries helping to reduce the budget allocated for imaging, but also in developing countries by giving them access to a modern and relatively cheap imaging method.
Recent developments have shown new and exciting areas for CEUS, which might have an even greater impact on ultrasound imaging, is in molecular imaging. Microbubbles, or the so-called third generation agents, can be targeted to specific tissue types to delineate pathologies which would otherwise be difficult to detect, or can be used for therapeutic purposes such as drug delivery and gene therapy. The most interesting clinical applications will be in cancer and cardiovascular disease, which are the most prevalent causes of death in humans in developed countries.