Multi-Frequency Processing for Lumen Enhancement with Wideband Intravascular Ultrasound

The application of high frequency ultrasound is the key to higher resolution intravascular ultrasound (IVUS) images. The need to further improve the IVUS spatial resolution may drive the transducer center frequency even higher than the current 40 MHz range. However, increasing the center frequency may be challenging as it leads to stronger scattering echoes from blood. The high level of blood scattering echoes may obscure the arterial lumen and make image interpretation difficult. Blood backscatter levels increase with transmission center frequency at a much greater rate compared to arterial tissue. These different frequency dependencies provide a potential method to distinguish blood from tissues by means of multi-frequency processing techniques. To obtain a good blood-tissue contrast with sufficient signal-to-noise ratio, a system with a wider bandwidth is highly desirable. The method described in this paper is based on the ratio of the received signal power between the high (60 MHz) and low (25 MHz) frequency ranges from a novel 40 MHz wideband IVUS catheter. In this paper we will present our in vitro experiment work on porcine blood and a tissue-mimicking arterial wall. Results of multi-frequency processing indicate that blood, at higher frequencies, has a greater backscatter power that is 8X greater than arterial tissue, suggesting this technique will provide a greater contrast between the blood-wall lumen boundary for coronary imaging.

Name thesis:degree_name

MS in Biomedical Engineering

Discipline thesis:degree_discipline

Biomedical and General Engineering

Year dc:date.available

2010

Author dc:creator

• Carrillo, Rory A

Contributors dc:contributor

• Lily Laiho

• Intravascular Ultrasound
• Multi-Frequency Processing
• Lumen Enhancement
• Bioimaging and Biomedical Optics
• Biomedical Devices and Instrumentation
• Signal Processing

Identifier

10.15368/theses.2010.152

OAI identifier oai:identifier

oai:digitalcommons.calpoly.edu:theses-1407