Intrinsic fluorescence and diffuse reflectance spectroscopy identify superficial foam cells in coronary plaques prone to erosion.
OBJECTIVE
Foam cells perform critical functions in atherosclerosis. We hypothesize that coronary segments with superficial foam cells (SFCs) situated in a region of interest with a depth of 200 mum can be identified using intrinsic fluorescence spectroscopy (IFS) and diffuse reflectance spectroscopy (DRS). This is a key step in our ongoing program to develop a spectroscopic technique for real-time in vivo diagnosis of vulnerable atherosclerotic plaque.


RESULTS
We subjected 132 human coronary segments to in vitro IFS and DRS. We detected SFCs in 13 thick fibrous cap atheromas and 8 pathologic intimal thickening (PIT) lesions. SFCs colocalized with accumulations of smooth muscle cells and proteoglycans, including hyaluronan (P<0.001). Two spectroscopic parameters were generated from analysis of IFS at 480 nm excitation and DRS. A discriminatory algorithm using these parameters identified specimens with SFC area >40%, 20%, 10%, 5%, 2.5%, and 0% of the region of interest with 98%, 98%, 93%, 94%, 93%, and 90% accuracy, respectively.


CONCLUSIONS
Our combined IFS and DRS technique accurately detects SFCs in thick fibrous cap atheromas and PIT lesions. Because SFCs are associated with histological markers of plaque erosion, our spectroscopic technique could prove useful in identifying vulnerable plaques.
Angheloiu
George O
GO
Spectroscopy Laboratory , Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. angheloiugo@upmc.edu
Arendt
Joseph T
JT
Müller
Markus G
MG
Haka
Abigail S
AS
Georgakoudi
Irene
I
Motz
Jason T
JT
Scepanovic
Obrad R
OR
Kuban
Barry D
BD
Myles
Jonathan
J
Miller
Frank
F
Podrez
Eugene A
EA
Fitzmaurice
Maryann
M
Kramer
John R
JR
Feld
Michael S
MS