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