Figure 1.
µOCT instrumentation schematic.
System diagram. RM: reference mirror. OL: objective lens. EC: environmental chamber. AO: analog output board. G: grating. IMAQ: image acquisition board. L: camera lens. LSC: line scan camera. SMF: single mode fiber. PC: personal computer. RAID: redundant array of independent disks. CL: Camera Link cable.
Figure 2.
Volumetric analysis of macrophage cell and cholesterol crystal by µOCT.
Cross-sectional µOCT images of macrophage cell in coronary artery (A) and cultured macrophage cell with cholesterol crystal (B). Long and short axes (green dotted lines) of macrophage were measured at the slice with biggest cross-sectional cell area. Each 2-D area of macrophage cell and cholesterol crystals was measured. Scale bars = 50 µm.
Figure 3.
Representative image of cultured macrophage cell with cholesterol crystal.
A. Representative image of a macrophage with a cholesterol crystal. The macrophage on the right demonstrated highly scattering constituents inside its cytoplasm (yellow arrow). B, C. The Cross sectional images of the macrophage on the right. D, E. Polarization microscopy confirmed that the inclusions are cholesterol crystals (red arrow). Scale bars = 50 µm.
Figure 4.
Discrepancy image of cultured macrophage cell with cholesterol crystal.
A. Discrepancy image of macrophage with cholesterol crystal. Two macrophages determined to contain cholesterol crystals by polarized light microscopy (B, C red arrow) did not show definitive evidence of crystals on the µOCT image (yellow arrow). Scale bars = 50 µm
Figure 5.
Correlation of cholesterol crystal size between µOCT and polarization microscopy.
Cholesterol crystal sizes assessed by µOCT demonstrated significant correlations with those by polarization microscopy (r = 0.63 p<0.01).
Table 1.
µOCT measured parameters from human coronary artery ex vivo.
Figure 6.
Representative images of cholesterol crystal in human tissue.
The upper figure is a representative image of cholesterol crystal in human coronary artery, characterized by multiple intense reflections from its top and bottom surfaces (A). An en face image of a cholesterol crystal (B) is shown in panel (C). This transverse cut shows the typical angles associated with cholesterol monohydrate crystals of (83.7 (acute) and 104.2 (obtuse) degrees). Scale bars = 100 µm
Figure 7.
Macrophage cells in coronary artery.
A. Macrophages (green arrow) seen by µOCT appear as highly scattering ellipsoidal structures that can be clearly distinguished from other coronary artery cellular and subcellular components. The macrophage on the right contains a highly scattering inclusion that is consistent with a cholesterol crystal (red arrow). B. Necrotic core fibroatheroma with macrophages (yellow arrow) infiltrating the cap. C. Some macrophages attenuated the OCT signal deep to the cells. Scale bars = 100 µm (A, B), 50 µm (C).
Figure 8.
Macrophage cells with highly scattering constituents.
A. Representative image of macrophage cells in human coronary artery contained highly scattering inclusions within their cytoplasm. B. Three-dimensional image of a macrophage showing a highly scattering inclusion (red-yellow color) within its cytoplasm (red arrow).