Simultaneous morphological and biochemical endogenous optical imaging of atherosclerosis.
OBJECTIVE
The aim of this study was to validate novel imaging technology for simultaneous morphological and biochemical endogenous optical imaging of coronary atherosclerotic plaque.


RESULTS
Optical coherence tomography (OCT) generates high-resolution 3D images of plaque morphology and endogenous fluorescence lifetime imaging microscopy (FLIM) characterizes biochemical composition. Both imaging modalities rely on plaque's intrinsic optical characteristics, making contrast agents unnecessary. A multimodal OCT/FLIM system was utilized to generate luminal biochemical maps superimposed on high-resolution (7 µm axial and 13 µm lateral) structural volumetric images. Forty-seven fresh postmortem human coronary segments were imaged: pathological intimal thickening (PIT, n = 26), fibroatheroma (FA, n = 12), thin-cap FA (TCFA, n = 2), and fibrocalcific plaque (CA, n = 7), determined by histopathology. Multimodal images were evaluated, and each plaque identified as PIT, FA, TCFA, or CA based on expert OCT readers, and as having high-lipid (HL), high-collagen (HC), or low-collagen/low-lipid (LCL) luminal composition based on linear discriminant analysis of FLIM. Of 47 plaques, 89.4% (42/47) of the plaques were correctly identified based on OCT/FLIM evaluation using tissue histopathology and immunohistochemistry as the gold standard. Four of the misclassifications corresponded to confusing PIT with HL luminal composition for FA with HL cap. The other corresponded to confusing FA with a HC cap for FA with an LCL cap.


CONCLUSIONS
We have demonstrated the feasibility of accurate simultaneous OCT/FLIM morphological and biochemical characterization of coronary plaques at spatial resolutions and acquisition speeds compatible with catheter-based intravascular imaging. The success of this pilot study sets up future development of a multimodal intravascular imaging system that will enable studies that could help improve our understanding of plaque pathogenesis.
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA javierjo@tamu.edu.
Javier A
JA
Jo
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
Jesung
J
Park
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
Paritosh
P
Pande
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
Sebina
S
Shrestha
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
Michael J
MJ
Serafino
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
J de Jesus
Jde J
Rico Jimenez
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, USA.
Fred
F
Clubb
Department of Cardiology, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX, USA.
Brian
B
Walton
Department of Cardiovascular Pathology Research, Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, TX, USA.
L Maximilian
LM
Buja
University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Jennifer E
JE
Phipps
University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
Marc D
MD
Feldman
Autopsy and Pathology Services, Houston, TX, USA.
Jessie
J
Adame
Department of Biomedical Engineering, Texas A&M University, 5062 Emerging Technologies Building, 3120 TAMU, College Station, TX 77843-3120, USA.
Brian E
BE
Applegate
D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000473:pathology; D003331:Coronary Vessels / Q000473:pathology; D005240:Feasibility Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D066298:In Vitro Techniques; D008856:Microscopy, Fluorescence; D064847:Multimodal Imaging; D010865:Pilot Projects; D041623:Tomography, Optical Coherence
Atherosclerosis; Fluorescence lifetime imaging; Intravascular imaging; Optical coherence tomography; Vulnerable plaque