This study tested whether near-infrared (NIR) photonic analysis can detect inflammatory biomarkers like C-reactive protein (CRP) and B-type natriuretic peptide (BNP) in blood, and predict vulnerable plaque components such as cholesterol, collagen, elastin and macrophages in arterial tissue samples. The study used NIR spectroscopy to analyze human and rabbit aorta samples both in vitro and in vivo. Results showed NIR could accurately identify plaque structures and predict levels of inflammatory biomarkers, suggesting it may help detect dangerously unstable atherosclerotic plaques.

1. A Novel Method for Detection of CRP and Other Elements of
Arterial Inflammation
Paul Cherukuri1
, Silvio Litovsky1
, MD, Ward Casscells1
, MD, James T. Willerson1
, MD, Morteza Naghavi1
, MD, Robert
Lodder2
, PhD
University of Texas – Houston1,
Department of Cardiology and the Texas Heart Institute1
, Houston, TX
University of Kentucky2
, College of Pharmacy2
, Lexington, KY
Near-IR Spectrometry
Near-IR spectrometry uses the absorption, emission, or
scattering of light in the near-infrared portion of the
electromagnetic spectrum (700 - 3000 nm) by atoms or
molecules to determine sample composition or characteristics.
Near-IR Spectrometry
Near-IR spectrometry uses the absorption, emission, or scattering of light in the near-infrared portion of the electromagnetic spectrum (700 - 3000 nm) by atoms or molecules to determine sample composition or characteristics.
Texas Heart Institute®
C
Optical Biopsy Results
Predicted
Actual
Thick cap overlying lipid core Thick Fibrous Plaque
Vulnerable Plaque(thin cap, overlying
large lipid core
Eachstripthenscannedunder
referencevisiblemicroscopefor
histologicalcorrelation
EachaorticstripwascannedinaNIR
spectrometer1100-2500nm
ShowDrawingHERE
of Plaquesegmentedintostrips
Eachaortacutintocircumferentialsegments
Humanaorta-invitro
n=6aorta
EachaorticstripwasscannedinaNIR
spectrometer1100-2500nm
Catheterusedwtihatunablelaserlightsource
andspectracollectedasaortawaswithdrawn
Insertcatheterintofemoralarteryuptothelevelof
oftheaorticarch
Rabbitaorta-invivo
n=6aorta
MethodlogyforPhotonicdeterminationofplaquecomponents
Plaquesamples
Material and Methods
Results
Conclusions
•
Introduction
•
The purpose of this study was to test the hypothesis that
dynamic near-infrared (NIR) photonic analysis is capable of
detecting inflammatory vulnerable blood components such as
CRP and BNP. Furthermore, this study also tested the
hypothesis that NIR was capable of accurately predicting
vulnerable structural components such as cholesterol, collagen
and elastin, and macrophage content within the arterial walls
of both in vitro (human) and in vivo (rabbit) aorta samples.
What is a vulnerable
plaque?
A vulnerable atherosclerotic
plaque is a highly active region
of inflammation within an
arterial wall that in the presence
of an appropriate triggering
mechanism, ruptures, erodes, or
ulcerates.
Structure:Vulnerable plaques
typically contain a substantial
lipid core (>40%) composed
primarily of cholesterol and
cholesterol esters covered by a
thin (typically <100 microns)
fibrous cap, which is composed
mainly of collagen and elastin
with a dense macrophage
infiltrate located
subendothelially.
Clinical significance:
Rapid thrombus formation after
rupture overlying the plaque
produces a rapid occlusion and
is the major cause of sudden
cardiac death.
What is vulnerable blood?
Constituents within the blood
that have been shown to be
indicators of inflammation or
elevated in cardiac disease,
such as CRP(C-reactive
protein) and BNP(B-naturietic
peptide.
Clinical significance:
CRP is an indicator of
inflammation. It has been shown
that people who died sudden
cardiac death had an abundance
of CRP in the blood, although
few had had outward signs of
heart problems. The finding
bolsters the case for using CRP
as a diagnostic tool to detect
heart ailments because autopsies
revealed that high CRP
concentrations in blood coincide
with the presence of dangerously
unstable atherosclerotic plaques
in the coronary arteries.
Near-IR Spectrometry
Near-IR spectrometry uses the absorption,
emission, or scattering of light in the near-infrared
portion of the electromagnetic spectrum (700 -
3000 nm) by atoms or molecules to determine
sample composition or characteristics.