Research

Optical Coherence Tomography Applications in Cardiac Electrophysiology

The goal of the Structure Function Laboratory at Columbia University is to develop optical imaging tools to address unmet clinical needs. Cardiovascular disease is the leading cause of morbidity and mortality in the United States. Progress within the cardiovascular field towards early diagnosis, increased efficacy in therapy and understanding the underlying mechanisms of cardiovascular diseases have been aided in part by advances in medical imaging technologies. Optical coherence tomography (OCT) is a non-invasive imaging modality that provides depth-resolved, high-resolution images of tissue microstructure in real-time. OCT provides subsurface imaging of depths 1-2mm in cardiac tissue with high spatial resolution (10um) in three dimensions and high sensitivity in vivo. Fiber-based OCT systems can be incorporated into catheters to image internal organs. These features have made OCT a powerful tool for cardiovascular imaging, with major contributions to the field of coronary artery disease.  We aim to develop high resolution systems to image the myocardium, coupled with real time tissue characterization for guidance of surgical and therapeutic procedures.  Importantly, we have noticed common structural similarities to other organ systems, and have begun recent projects applying image processing for characterization of early breast cancer lesions and for analyzing the ultrastructure of the human cervix.

Research Projects

Spectroscopic Analysis of the Myocardium

  • Spectroscopic Optical Coherence Tomography (SOCT) using time-frequency analysis to analyze depth resolved spectral characteristics of biological tissue.  This provides an additional contrast within standard OCT images without integration of an additional optical modality.
  • Near infrared spectroscopy (NIRS) collects diffuse light to analyze the composition of biological tissue at greater depths than OCT.  We are developing custom fiber probes optimized for interrogating the myocardium.

Structure – Function of the Myocardium and Cervix

  • Development of image processing algorithms to quantify myofiber orientation and correlate the orientation to action potential propagation properties
  • Development of image processing algorithms to characterize the tissue composition of the myocardium and how it changes with remodeling
  • Correlation of electrical and mechanical function to tissue composition and fiber organization within the myocardium and cervix
Christine Fleming Hendon, Myofiber orientation, algorithm, heart, Christine Hendon, Christine Fleming, oct imaging

Myofiber orientation measurements within 3D OCT image sets. En face images from 3 regions within the right ventricular free wall of a rabbit (ex vivo). Output of algorithm is overlayed on gray scale image, showing local myofiber orientation

Translation of Optical Coherence Tomography (OCT) and Near Infrared Spectroscopy Substrate Guided Radiofrequency Ablation (RFA) Therapy

  • Development of image processing algorithms to assess energy delivery to the myocardium by radiofrequency ablation by analysis of optical coherence tomography images
Christine Fleming Hendon, OCT radiofrequency ablation lesion, myocardium, heart, Christine Fleming, Christine Hendon, optical coherence tomography, oct imaging

By visualizing the plane parallel to the surface of three dimensional image sets of samples fixed in formalin, fiber organization was observed within untreated sites, and fiber organization was not visible within the RFA lesion Areas with RFA lesions lost visible fiber structure within OCT volumes and also lost the banding appearance within B-scan images. Data obtained with a standard spectral domain OCT system, without polarization diverse detection and 10µm resolution

Christine Fleming Hendon, OCT Forward Imaging Catheter, Prototype, heart, in vivo, Christine Fleming, Christine Hendon, optical coherence tomography

(a) Optical design of forward imaging catheter to provide cone scanning. (b) image of prototype catheter. (c) simulation of spot profile, 30um spot size. (d) measured spot profile from prototype, 30um spot size. (e) example image taken with forward imaging probe, finger showing layers and sweat glands

  • Optical and mechanical design and prototyping of catheters for imaging in vivo. Our current focus is the development of forward imaging optical coherence tomography catheters to image while in contact with the heart wall in vivo.

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