Noninvasive Determination of Spatially Resolved and Time-Resolved Tissue Perfusion in Humans During...
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Noninvasive Determination of Spatially Resolved and Time-Resolved Tissue Perfusion in Humans During Nitric Oxide Inhibition and
Inhalation by Use of a Visible-Reflectance Hyperspectral Imaging Technique
Karel J. Zuzak ,at all (Circulation. 2001;104:2905-2910.)
Nitric Oxide (NO)Endothelium-derived relaxing factor (EDRF)
NADPHNADPH OO22 +
Production of NO
Effector mechanisms of NO
Endothelial Endothelial CellCell
Smooth Muscle CellSmooth Muscle Cell
CaCa2+2+
NOSGC
cGMcGMPP
NO-dependent NO-dependent VasodilatorsVasodilators -Acetylcholine -Bradykinin
Blood Flow Blood Flow Shearing ForcesShearing Forces
R
Lumen
CaCa2+2+
K+
Cardiovascular disease
Diabetes mellitusType I,II Cardiovascula
r disease
Endothelial dysfunction
Methods
• Noninvasively • Real time• in vivo
Spectroscopic Determination of Percentage of HbO2
541576
555
Imaging system.
•Liquid crystal tunable filter (LCTF)•Charge-coupled device detector (CCD)•Analog-to-digital converter (ADC)
Instrumentation
• A quartz tungsten halogen light source (Oriel Instruments)
• A mirror ,Liquid crystal tunable filter(LCTF) (Cambridge Research and Instrumentation)
• Lens (Nikon)
• CCD detector (Roper Scientific)
• GX1P computer (Dell)
Spectroscopic Determination of Percentage of HbO2
Reference spectra of a 100% HbO2 and deoxy-Hb Standard methods using blood collected from a
healthy, nonsmoking 7 mL of hemolysates was mixed with 30 mg of
sodium dithionite The HbO2 spectrum displays distinct peaks at 541
and 576 nm Deoxy-Hb displays a single peak at 555 nm
Study Population
• 9 nonsmoking healthy (5 men and 4 women)• Average age of 32±4 years• Clinical history, physical examination• ECG, and routine laboratory analyses• No evidence of cardiovascular disease
Protocol
1. refrained drinking alcohol and beverages containing caffeine for ≥12 hours
Protocol
1. breathed room air Tem~22°C
5% dextrose in water (D5W) 1 mL/min
NG-monomethyl-L-arginine (L-NMMA) 4 to 8 mol/min
20 min
2. NO 80 ppm
blood flow was measured by venous occlusion plethysmography(Hokanson)
NOS inhibitor
during which time hyperspectral images were collected
Statistical Analysis
• Differences between population means were compared by a 2-tailed
Results
Results
Results
Discussion
• Noninvasive techniques for providing rapid, repetitive assessment of tissue perfusion could be of considerable utility in the management of a variety of vascular diseases. In addition to assessing and quantifying the concentration of a specific chemical species, such as HbO2 and deoxy-Hb,
Discussion
• hyperspectral imaging provides representations of the spatial distribution of a molecular species at a given time or over time.
• Accordingly, acquisition of a time-resolved profile representing the spatial dynamics of physiologically important molecules indicative of tissue perfusion could prove useful in assessing the efficacy of a given therapeutic intervention on vascular disease.
Thank You