Guiding Treatment and Study of Atherosclerotic Cardiovascular Disease

We research the development of an intravascular bi-modal technology for diagnosis of arterial wall pathologies including rupture-prone (vulnerable) atherosclerotic plaques. Our goal is to optimize, construct and test a unique clinically-compatible system that combines fast, time-resolved fluorescence spectroscopy (TRFS) to dynamically evaluate atherosclerotic plaque composition under pull-back motion, with intravascular ultrasound (IVUS) that allows for both visual reconstruction of plaque microanatomy and guidance of TRFS measurements. The resulting system will enable detection and monitoring of biochemical, functional and structural features of atherosclerotic lesions with clinical relevance (e.g. predictive of plaque rupture).

This bi-modal intravascular technique targets advancement of new paradigms for diagnosis and management of atherosclerotic cardiovascular disease that affects >80 million individuals in the US and represents the leading cause of death (>830,000/year). The proposed approach of integrating TRFS with IVUS should improve the diagnostic ability of IVUS, the most widely used intravascular imaging technique in interventional cardiology. Examples of important applications for this bimodal technology in patients who are candidates for transluminal interventional procedures include: a) If a plaque is more accurately classified with TRFS-IVUS and the risk of rupture can be predicted, patients could be identified and treated prior to symptoms or rupture. b) If the TRFS- IVUS system allows better understanding of atherosclerotic plaque pathologies it could be used to predict which patients would benefit from therapy. c) In the large number of patients who undergo repeat catheterization, it should allow the clinician to monitor the effects of various pharmacologic (e.g lipid lowering drugs) interventions.

Clinical collaborators: Jeffrey Southard , John W. Bishop, William Ferrier

Multimodal FLIm – IVUS system

Bimodal system schematic. (a) Fluorescence lifetime imaging (FLIm) subsystem: UV pulses from the laser are sent through a dichroic within the wavelength selection module (WSM) into the catheter’s fiberoptic. The fluorescence emission is collected by the same fiberoptic, directed back into the WSM that spectrally resolves the emission, detected by a multichannel plate photomultiplier (MCP-PMT), and amplified by a preamplifier (AMP). IVUS subsystem: Boston Scientific iLab IVUS imaging system consists of an integrated motor drive that rotates a single element 40-MHz IVUS transducer (retrieved from Atlantis SR Pro coronary imaging catheter) at a constant speed of 1800 rpm. Bimodal imaging catheter: IVUS transducer and side-viewing fiberoptic integrated in a parallel design. [see (b)] Data acquisition (DAQ) and control module: Digitizer records analog signals from both FLIm and IVUS subsystems and upload the data to the embedded controller through PXIe bus. The controller communicates with motion controllers in charge of the catheter’s helical scanning motion. (b) Completed assembly of the bimodal catheter and the imaging section. Fiberoptic and IVUS transducer enter the imaging section sequentially to perform helical scanning. (c) Photo of the compact assembly of catheter, motion control, and FLIm/IVUS system components.

 

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