Real time intravascular ultrasound elastography with rotating single element transducers

Intravascular Ultrasound (IVUS) is the gold standard for imaging the morphology of plaques in coronary arteries, but conventional B-mode images do not give sufficient information for plaque characterization. It has been shown that Elastography (strain imaging) with I´VUS can differentiate between soft and hard plaques. This work presents a system for IVUS Elastography using rotating single element transducers. It is capable of calculating and displaying strain images in real time. A time efficient strain estimation algorithm was adapted for use with IVUS, custom made hardware was developed for rf-data acquisition. Phantom studies and in vitro experiments with carotid arteries were conducted to verify this approach. The performance of the strain estimation under the influence of artifacts due to catheter angulation was also assessed. The results show that elastography is feasible with single element transducers. Local strains of up to 2% can be estimated. With different catheter angulations a mean normalized correlation coefficient >0.8 is obtained without correction in angular direction.