New methods for time-resolved fluorescence spectroscopy data analysis based on the Laguerre expansion technique--applications in tissue diagnosis.
OBJECTIVE
A new deconvolution method for the analysis of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) data is introduced and applied for tissue diagnosis.


METHODS
The intrinsic TR-LIFS decays are expanded on a Laguerre basis, and the computed Laguerre expansion coefficients (LEC) are used to characterize the sample fluorescence emission. The method was applied for the diagnosis of atherosclerotic vulnerable plaques.


RESULTS
At a first stage, using a rabbit atherosclerotic model, 73 TR-LIFS in-vivo measurements from the normal and atherosclerotic aorta segments of eight rabbits were taken. The Laguerre deconvolution technique was able to accurately deconvolve the TR-LIFS measurements. More interesting, the LEC reflected the changes in the arterial biochemical composition and provided discrimination of lesions rich in macrophages/foam-cells with high sensitivity (> 85%) and specificity (> 95%). At a second stage, 348 TR-LIFS measurements were obtained from the explanted carotid arteries of 30 patients. Lesions with significant inflammatory cells (macrophages/foam-cells and lymphocytes) were detected with high sensitivity (> 80%) and specificity (> 90%), using LEC-based classifiers.


CONCLUSIONS
This study has demonstrated the potential of using TR-LIFS information by means of LEC for in vivo tissue diagnosis, and specifically for detecting inflammation in atherosclerotic lesions, a key marker of plaque vulnerability.
Jo
J A
JA
Department of Biomedical Engineering, Texas A&M University, 3120 TAMU, 337 Zachry Bldg., College Station, TX 77843-3120, USA. javierjo@bme.tamu.edu
Marcu
L
L
Fang
Q
Q
Papaioannou
T
T
Qiao
J H
JH
Fishbein
M C
MC
Beseth
B
B
Dorafshar
A H
AH
Reil
T
T
Baker
D
D
Freischlag
J
J
D000818:Animals; D001161:Arteriosclerosis / Q000175:diagnosis* / Q000473:pathology; D003199:Computer Systems; D005487:Foam Cells; D006801:Humans; D007249:Inflammation; D007834:Lasers; D008264:Macrophages; D011817:Rabbits; D012815:Signal Processing, Computer-Assisted; D013050:Spectrometry, Fluorescence; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods; D013995:Time