Ultrasound Vector Flow Imaging, a Promising Technique towards a New Carotid Atheroma Risk Stratification
Résumé
Atheroma plaques are often found in the anatomical bifurcation area. The carotid bifurcation atheroma plaque is one of the most studied atheroma localizations because its evolution leads to a significant risk of morbidity. Currently, MRI (Magnetic Resonance Imaging) is the gold standard in carotid plaque imaging thanks to its high resolution. However, MRI is limited by its time constraint and cost. On the other hand, US (ultrasound) is limited in sensitivity and specificity to identify the atheroma plaque composition (lipidic or hemorrhagic components). This chapter highlights the advantages of new diagnostic approaches that can be implemented to enhance a conventional ultrasound system. Hereinafter, we analyze the new approach from different points of view: physical concepts, medical advantages, comparison with classical approaches, etc. Ultrasound Vector Flow Imaging (UVFI) appears to be a promising technic, but the indications in current practice have to be defined. Data that were previously hard to obtain in vivo can now be available to any sonographer in near real-time. The velocity vectors can be precisely calculated as well as the wall constraints. Atheroma plaque composition could thus be defined more precisely and provide a new risk stratification scale. The main disadvantage of ultrasound can also be greatly diminished by the precision provided by this technique. Indeed, the interobserver variability can be smoothed by a precise definition of the measured vector. Consequently, more rigorous monitoring can be achieved on the patient and provide as well as an additional argument to support doctors and surgeons’ decision in their therapeutic strategy.