Dr. Xi Chen Profile

Dr. Xi Chen

SPIE Involvement:

Author

Publications (5)

SPIE Journal Paper | 30 September 2020 Open Access

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

Xi Chen, Wihan Kim, Michael Serafino, Zheng Tan, Javier Jo, Brian Applegate

JBO, Vol. 25, Issue 09, 096010, (September 2020) https://doi.org/10.1117/12.10.1117/1.JBO.25.9.096010

KEYWORDS: Optical coherence tomography, Endoscopes, Fluorescence lifetime imaging, Luminescence, Cladding, Imaging systems, Arteries, Absorption, Silica, Polishing

Read Abstract +

Significance: Detailed biochemical and morphological imaging of the plaque burdened coronary arteries holds the promise of improved understanding of atherosclerosis plaque development, ultimately leading to better diagnostics and therapies. Aim: Development of a dual-modality intravascular catheter supporting swept-source optical coherence tomography (OCT) and frequency-domain fluorescence lifetime imaging (FD-FLIM) of endogenous fluorophores with UV excitation. Approach: We instituted a refined approach to endoscope development that combines simulation in a commercial ray tracing program, fabrication, and a measurement method for optimizing ball-lens performance. With this approach, we designed and developed a dual-modality catheter endoscope based on a double-clad fiber supporting OCT through the core and fluorescence collection through the first cladding. We varied the relative percent of UV excitation launched into the core and first cladding to explore the potential resolution improvement for FD-FLIM. The developed catheter endoscope was optically characterized, including measurement of spatial resolution and fluorescent lifetimes of standard fluorophores. Finally, the system was demonstrated on fresh ex vivo human coronary arteries. Results: The developed endoscope was shown to have optical performance similar to predictions derived from the simulation approach. The FLIM resolution can be improved by over a factor of 4 by primarily illuminating through the core rather than the first cladding. However, time-dependent solarization losses need to be considered when choosing the relative percentage. We ultimately chose to illuminate with 7% of the power transmitting through the core. The resulting catheter endoscope had 40-μm lateral resolution for OCT and <100 μm lateral resolution for FD-FLIM. Images of ex vivo coronary arteries are consistent with expectations based on histopathology. Conclusions: The results demonstrate that our approach for endoscope simulation produces reliable predictions of endoscope performance. Simulation results guided our development of a multimodal OCT/FD-FLIM catheter imaging system for investigating atherosclerosis in coronary arteries.

DOWNLOAD PAPER

Proceedings Article | 14 March 2018 Presentation

Automatic detection of macrophages/foam cells in coronary atherosclerotic plaques based on fluorescence lifetime imaging (FLIM) (Conference Presentation)

Jose Rico-Jimenez, Michael Serafino, Xi Chen, Sebina Shrestha, Wihan Kim, Brian Walton, Brian Applegate, Javier Jo

Proceedings Volume 10471, 1047105 (2018) https://doi.org/10.1117/12.2288606

KEYWORDS: Fluorescence lifetime imaging, Multispectral imaging, Foam, Microscopy, Image analysis, Machine learning, Tissues, Receivers, Statistical analysis

Read Abstract +

Proceedings Article | 14 March 2018 Presentation

Design and validation of the ball lens-based intravascular catheter for fluorescence lifetime imaging microscopy of atherosclerosis (Conference Presentation)

Xi Chen, Wihan Kim, Michael Serafino, Zheng Tan, Brian Walton, L. Maximilian Buja, Jessie Adame, Javier Jo, Brian Applegate

Proceedings Volume 10471, 1047102 (2018) https://doi.org/10.1117/12.2287447

KEYWORDS: Fluorescence lifetime imaging, Microscopy, Endoscopes, Luminescence, Endoscopy, Tissues, Fiber optics, Performance modeling, Zemax, Polishing

Read Abstract +

Proceedings Article | 25 January 2018 Presentation

Design and validation of the ball lens-based intravascular catheter for fluorescence lifetime imaging microscopy of atherosclerosis (Conference Presentation)

Xi Chen, Wihan Kim, Michael Serafino, Javier Jo, Brian Applegate

Proceedings Volume 9689, 968932 (2018) https://doi.org/10.1117/12.2211764

Proceedings Article | 1 May 2017 Presentation

Toward intravascular morphological and biochemical imaging of atherosclerosis with optical coherence tomography (OCT) and fluorescence lifetime imaging (FLIM) (Conference Presentation)

Xi Chen, Wihan Kim, Michael Serafino, Brian Walton, Javier Jo, Brian Applegate

Proceedings Volume 10060, 1006007 (2017) https://doi.org/10.1117/12.2256676

KEYWORDS: Shortwaves, Optical coherence tomography, Fluorescence lifetime imaging, Imaging systems, Endoscopes, Infrared imaging, Lens design, Arteries, Therapeutics, Near ultraviolet

Read Abstract +

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years