Brendan Mulcahy
High Resolution Ultrasound

SchoolSaint Ignatius High School • Cleveland, Ohio

ProgramScience Internship

MentorAaron Fleischman, PhD

DepartmentBiomedical Engineering, Cleveland Clinic

mRI™: myRESEARCH illuminated

Hypothesis: High frequency ultrasonic transducers are used to diagnose intravascular diseases. Miniaturized transducers, that are focused, and broadband can be fabricated using MEMS (Micro-electro-mechanical systems) technology to generate high resolution images of the tissue. Harmonic imaging can be employed to further improve the resolution, providing different (nonlinear) information from the tissue than is provided by standard fundamental imaging.

Methodology: Ultrasonic transducers are made by applying air pressure to a piezoelectric polymer membrane (PVDF TrFE). They are then integrated with electronics to amplify the detected echoes. Pulse inversion technique is used to amplify and generate the first harmonics. 360° views of the human coronary arteries are obtained by rotating the transducer inside the vessel. The echoes are then processed to create images of the tissue. The transducers fabricated are characterized by pulse-echo techniques to determine axial and lateral resolution.

Outcomes: A method to fabricate focused broadband transducers capable of imaging the coronary arteries with high resolution has been developed. Images with near histological resolution can be generated, and delineation of coronary artery is superior to that by commercial IVUS (intravascular ultrasound) systems. Harmonic imaging may further improve resolution to aid diagnosis of cardiovascular diseases.