Multi-frequency processing for lumen enhancement with wideband intravascular ultrasound

The need to further improve the spatial resolution of intravascular ultrasound (IVUS) may drive the transducer center frequency even higher than the current 40 MHz range. Using a higher frequency results in stronger scattering echoes from the blood and may hamper visualization of the arterial lumen. This paper presents a multi-frequency processing method to enhance the arterial lumen by extracting the different scattering characteristics between blood and arterial tissues. A novel wideband catheter enables transmitting a broadband excitation pulse and processing signals in different frequency ranges, allowing detection of the signal ratio between the high (60 MHz) and low (25 MHz) frequencies. To evaluate this method, an in vitro experiment with porcine blood will be described. The lumen enhancement method will be demonstrated in vivo in an animal study.